Subject: Determining Mass Size for Lehman Seismometer From: "Gary Lindgren" gel@................. Date: Mon, 31 Mar 2008 17:40:48 -0700 How do I determine the mass size of the pendulum for a Lehman seismometer. Is there a method to the madness? Gary Gary Lindgren 585 Lincoln Ave Palo Alto CA 94301 650-326-0655 www.blue-eagle-technologies.com cymonsplace.blogspot.com

How do I determine the mass size of the pendulum for a Lehman seismometer. = Is there a method to the madness?

Gary

 

Gary Lindgren

585 Lincoln Ave

Palo = Alto CA 94301

 

650-326-0655

 

www.blue-eagle-technologi= es.com

cymonsplace.blogspot.com=  

 

 

Subject: Re: Determining Mass Size for Lehman Seismometer From: lehmancj@........... Date: Tue, 1 Apr 2008 00:55:38 GMT > How do I determine the mass size of the pendulum for a Lehman seismometer. > Is there a method to the madness? > > Gary--just a note on the original determination of the mass. I chose a 5lb. piece of lead as it was available & handy. For the dimensions of the boom, the lead was not excessive weight, and seemed to be sufficient mass for stability, and was able to be supported by piano wire without undo fatigue. The system worked beyond our original expectations, but there have been modifications & improvements, so don't fear to experiment around with other suggestions that float by. A working design is empirical by nature--best wishes--Jim Lehman > > > > Gary Lindgren > > 585 Lincoln Ave > > Palo Alto CA 94301 > > > > 650-326-0655 > > > > www.blue-eagle-technologies.com > > cymonsplace.blogspot.com > > > > > > --------------------------------------------- This message was sent using Shentel WebMail. http://WebMail.Shentel.Net __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Determining Mass Size for Lehman Seismometer From: ChrisAtUpw@....... Date: Mon, 31 Mar 2008 22:38:55 EDT In a message dated 2008/04/01, gel@................. writes: > How do I determine the mass size of the pendulum for a Lehman seismometer. > Is there a method to the madness? > Gary Hi Gary, There is method in the madness! The period of a pendulum is independant of the mass, since the gravitational attraction and the moment of inertia both depend on M ! But you need ~the maximum radius of gyration, so you make the mass several times larger than the weight of the arm on it's own. But you don't want to stress the suspension too much. A mass of 1 to about 5 lbs is generally OK. Lead is dense, but difficult to fasten, so I generally use brass. Avoid iron, which is magnetic. Hope that this helps! Regards, Chris Chapman In a me= ssage dated 2008/04/01, gel@................. writes:

How do I determine the mass siz= e of the pendulum for a Lehman seismometer. Is there a method to the madness= ?
Gary


Hi Gary,

       There is method in the madness!

       The period of a pendulum is independant= of the mass, since the gravitational attraction and the moment of inertia b= oth depend on M !

       But you need ~the maximum radius of gyr= ation, so you make the mass several times larger than the weight of the arm=20= on it's own. But you don't want to stress the suspension too much.  A m= ass of 1 to about 5 lbs is generally OK. Lead is dense, but difficult to fas= ten, so I generally use brass. Avoid iron, which is magnetic.

       Hope that this helps!

       Regards,

       Chris Chapman Subject: Re: Determining Mass Size for Lehman Seismometer From: "Geoff" gmvoeth@........... Date: Tue, 1 Apr 2008 07:39:18 -0700 If you consider the science of external ballistics you will find the greater the mass and density the less effect air movemenr will have on it. Otherwise use a small mass several times the boom mass and put in all under a vacuum with magnetic damping. Static friction is the only nasty thing to deal with as I understand it. It tends to lock things into place till you get enough force to overcome it. If you do not have the ability to produce and maintain a vacuum I think a spherical shape may be the best for the mass. I have often thought it would be nice to have a very very sensitive bathroom scale and put a gallon of water on it then look for the noise level. Not sure of any of this it just seems common senseical :-) ----- Original Message ----- From: "Gary Lindgren" To: Sent: Monday, March 31, 2008 5:40 PM Subject: Determining Mass Size for Lehman Seismometer > How do I determine the mass size of the pendulum for a Lehman seismometer. > Is there a method to the madness? > > Gary > > > > Gary Lindgren > > 585 Lincoln Ave > > Palo Alto CA 94301 > > > > 650-326-0655 > > > > www.blue-eagle-technologies.com > > cymonsplace.blogspot.com > > > > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Tiltmeter Electronics From: "Chuck Burch" cjburch@........... Date: Wed, 02 Apr 2008 20:43:27 -0700 I'm wondering about electronics for a tiltmeter with capacitive sensors I'm building. My current plan is to use a transformer coupled bridge, current-to-voltage amplifier, phase sensitive detector, followed by filter and final gain. I have a circuit diagram for this scheme, but it's circa 1970 and I assume it can be improved with modern chips. Any suggestions? Chuck Burch __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Tiltmeter Electronics From: ChrisAtUpw@....... Date: Wed, 2 Apr 2008 11:36:06 EDT In a message dated 2008/04/02, cjburch@........... writes: > I'm wondering about electronics for a tiltmeter with capacitive sensors I'm > building. > My current plan is to use a transformer coupled bridge, current-to-voltage > amplifier, > phase sensitive detector, followed by filter and final gain. I have a > circuit diagram for this scheme, but it's circa 1970 and I assume it can be > improved with modern chips. Hi Chuck, George Bush at ke6pxp@....... has done quite a lot of work on the Mercury Tiltmeter published by the Scientific American about then. The original circuit needs to be improved very considerably. I helped George over the design using an LTC1043 switched capacitor bridge. He has a website at http://ntweb.mcn.org/gbush/Tiltmeter/tiltmeter%20Main.html DON'T bother with the Nuts and Volts circuit. It does not work well. There is another seismometer / tiltmeter circuit using water, as opposed to mercury, which also works very well at FMES. Contact Dave Nelson at davefnelson@....... Design and circuits are available. Regards, Chris Chapman In a me= ssage dated 2008/04/02, cjburch@........... writes:

I'm wondering about electronics= for a tiltmeter with capacitive sensors I'm building. 
My current plan is to use a transformer coupled bridge, current-to-voltage a= mplifier,
phase sensitive detector, followed by filter and final gain.  I have a=20= circuit diagram for this scheme, but it's circa 1970 and I assume it can be=20= improved with modern chips. 


Hi Chuck,

       George Bush at ke6pxp@....... has done quite a lot of work on the Mercury&nbs= p; Tiltmeter published by the Scientific American about then. The original c= ircuit needs to be improved very considerably. I helped George over the desi= gn using an LTC1043 switched capacitor bridge.

       He has a website at http://ntweb.mcn.or= g/gbush/Tiltmeter/tiltmeter%20Main.html

       DON'T bother with the Nuts and Volts ci= rcuit. It does not work well.

       There is another seismometer / tiltmete= r circuit using water, as opposed to mercury, which also works very well at=20= FMES. Contact Dave Nelson at davefnelson@....... Design and circuits are ava= ilable.

       Regards,

       Chris Chapman Subject: Question regarding leveling of vertical seismometer From: "Kay Wyatt" kwyatt@............. Date: Wed, 2 Apr 2008 12:22:33 -0700 Folks, A quick question regarding the leveling screws for a vertical = seismosmeter... If you look at the three leveling screws on the AS-1 seismometer at = http://www.amateurseismologist.com/, you see that there are two screws = on the end with the vertical support and one screw on the end near the = coil. It is obvious why only three screws are used. But is their a = reason for putting the single screw near the coil and not near the = vertical support. Also, wouldn't there be greater stability if the = single screw was actually a fixed pin, leaving the other two to be = adjustable screws? =20 Just wondering before I drill the base in my next vertical seismometer. Thanks, Kay Wyatt
Folks,
 
A quick question regarding the leveling screws = for a=20 vertical seismosmeter...
 
If you look at the three leveling screws on the = AS-1=20 seismometer at http://www.amateurseismologi= st.com/,=20 you see that there are two screws on the end with the vertical support = and one=20 screw on the end near the coil.  It is obvious why only three = screws are=20 used.  But is their a reason for putting the single screw near the = coil and=20 not near the vertical support.  Also, wouldn't there be greater = stability=20 if the single screw was actually a fixed pin, leaving the other two to = be=20 adjustable screws? 
 
Just wondering before I drill the base in = my next=20 vertical seismometer.
 
Thanks,
Kay Wyatt
 
 
Subject: Re: Question regarding leveling of vertical seismometer From: ChrisAtUpw@....... Date: Wed, 2 Apr 2008 16:18:00 EDT In a message dated 2008/04/02, kwyatt@............. writes: > If you look at the three leveling screws on the AS-1 seismometer at > http://www.amateurseismologist.com/, you see that there are two screws on the end > with the vertical support and one screw on the end near the coil. It is > obvious why only three screws are used. But is their a reason for putting the > single screw near the coil and not near the vertical support. Also, wouldn't > there be greater stability if the single screw was actually a fixed pin, leaving > the other two to be adjustable screws? > > Just wondering before I drill the base in my next vertical seismometer. Hi Kay, It shouldn't matter, but it is generally easier to put the lateral adjustment screws either side of the vertical support column and the longitudinal adjustment at the end of the arm. You have 'free' space here. I suggest the you make all three mounting screws of identical construction. If you have one peg leg you will have the problem of matching it's expansion with the other two. This is not too important for vertical instruments, but it is very important on a Lehman. Also, you generally get presented with a site of unknown slope direction. Being able to adjust all three screws is an advantage. I use a fairly thick baseplate and stainless steel bolts, nuts and washers. I drill the hole the same nominal OD as the bolt. I stick a SS nut on the underside of the basplate with two component acrylic glue eg Devcon Plastic Welder S-220 22045. You can also buy 'nut-serts' which you press into suitable holes with a vice or a press. I centre drill the end of the bolts and stick a suitable OD SS ball bearing in the V. Alternatively, you can file the end of the bolt to a cone with a small domed end. This helps prevent the seismometer position wandering as you make adjustments. I thread an ordinary nut onto the bolt, add a wavy washer and screw this into the top of the frame. After adjusting the levels I tighten compress the wavy washer with the free top nut. This largely prevents any creep due to differential expansion. I also use three 2" square x 1/8" thick SS ground plates. What you MUST NOT do is to use bolts and nuts / threaded holes of DIFFERENT materials, with different expansion coefficients. This will ~guarantee creep / drift problems. Regards, Chris Chapman In a me= ssage dated 2008/04/02, kwyatt@............. writes:

If you look at the three leveli= ng screws on the AS-1 seismometer at http://www.amateurseismologist.com/, you see that there are two= screws on the end with the vertical support and one screw on the end near t= he coil.  It is obvious why only three screws are used.  But is th= eir a reason for putting the single screw near the coil and not near the ver= tical support.  Also, wouldn't there be greater stability if the single= screw was actually a fixed pin, leaving the other two to be adjustable scre= ws? 

Just wondering before I drill the base in my next vertical seismometer.

Hi Kay,

       It shouldn't matter, but it is generall= y easier to put the lateral adjustment screws either side of the vertical su= pport column and the longitudinal adjustment at the end of the arm. You have= 'free' space here.
       I suggest the you make all three mounti= ng screws of identical construction. If you have one peg leg you will have t= he problem of matching it's expansion with the other two. This is not too im= portant for vertical instruments, but it is very important on a Lehman.
       Also, you generally get presented with=20= a site of unknown slope direction. Being able to adjust all three screws is=20= an advantage.
       I use a fairly thick baseplate and stai= nless steel bolts, nuts and washers. I drill the hole the same nominal OD as= the bolt. I stick a SS nut on the underside of the basplate with two compon= ent acrylic glue eg Devcon Plastic Welder S-220 22045.
       You can also buy 'nut-serts' which you=20= press into suitable holes with a vice or a press.
       I centre drill the end of the bolts and= stick a suitable OD SS ball bearing in the V. Alternatively, you can file t= he end of the bolt to a cone with a small domed end. This helps prevent the=20= seismometer position wandering as you make adjustments.
       I thread an ordinary nut onto the bolt,= add a wavy washer and screw this into the top of the frame. After adjusting= the levels I tighten compress the wavy washer with the free top nut. This l= argely prevents any creep due to differential expansion.
       I also use three 2" square x 1/8" thick= SS ground plates.
       What you MUST NOT do is to use bolts an= d nuts / threaded holes of DIFFERENT materials, with different expansion coe= fficients. This will ~guarantee creep / drift problems.

       Regards,

       Chris Chapman Subject: Re: Question regarding leveling of vertical seismometer From: John Lahr johnjan@........ Date: Wed, 02 Apr 2008 23:10:26 -0700 Hi Kay, The problem with a fixed pin at one end is that to change to level in the long direction, both of the other screws would need to be turned. This would probably mess up the tilt in the short direction. With three screws, the short-direction tilt and the long-direction tilt can be adjusted independently. Cheers, John At 12:22 PM 4/2/2008, you wrote: >Folks, > >A quick question regarding the leveling screws for a vertical seismosmeter... > >If you look at the three leveling screws on the AS-1 seismometer at >http://www.amateurseismologist.com/, >you see that there are two screws on the end with the vertical >support and one screw on the end near the coil. It is obvious why >only three screws are used. But is their a reason for putting the >single screw near the coil and not near the vertical support. Also, >wouldn't there be greater stability if the single screw was actually >a fixed pin, leaving the other two to be adjustable screws? > >Just wondering before I drill the base in my next vertical seismometer. > >Thanks, >Kay Wyatt > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Question regarding leveling of vertical seismometer From: Charles Patton charles.r.patton@........ Date: Thu, 03 Apr 2008 10:41:07 -0700 Hi John, Not necessarily. The geometry used for mirror mounts in optical bench work is that the fixed point is at the intersection of two lines at right angles to one another. The two screws are then on each of the lines respectively. That way the screws do not interact, i.e., they cause only orthogonal tilt on their particular axis. So translating that to a seismometer, put the fixed pin near the pivot point of the boom and offside in the short dimension (perpendicular to the boom (if a Lehman style, but similar rules for a vertical) -- probably in one corner) Place one screw way down the base on a line through the fixed pin and parallel to the boom. This will become the leveling screw. Place the other screw on a line at right angles to the fixed point and the just placed screw (probably in the corner across the pivot. This is now the tilt. The only other trick is to put enough weight on the base so that the center-of-mass is within the triangle formed by the fixed point and two screws (or use a long, triangular shaped base where all the parts are within the triangle. Mirror mounts typically use springs to hold the mounts together, rather than gravity) So even if you use three screws, this geometry will make life much easier when adjusting as there won't be axis interactions when doing the final adjustments using only the two screws at the ends of the right angle. Refinements are to make the design fully kinematic by using a tetrahedral divot for the fixed point ball end to rest in, a tri-angular groove aligned along the line of the fixed point and the screw ball end, and finally a flat plate for the final screw ball end. This constrains the whole fixture so it doesn't slide or twist on the resting base. Charles Patton John Lahr wrote: > Hi Kay, > > The problem with a fixed pin at one end is that to change to level in > the long direction, both of the other screws would need to be turned. > This would probably mess up the tilt in the short direction. > > With three screws, the short-direction tilt and the long-direction tilt > can be adjusted independently. > > Cheers, > John > > At 12:22 PM 4/2/2008, you wrote: >> Folks, >> >> A quick question regarding the leveling screws for a vertical >> seismosmeter... >> >> If you look at the three leveling screws on the AS-1 seismometer at >> http://www.amateurseismologist.com/, >> you see that there are two screws on the end with the vertical support >> and one screw on the end near the coil. It is obvious why only three >> screws are used. But is their a reason for putting the single screw >> near the coil and not near the vertical support. Also, wouldn't there >> be greater stability if the single screw was actually a fixed pin, >> leaving the other two to be adjustable screws? >> >> Just wondering before I drill the base in my next vertical seismometer. >> >> Thanks, >> Kay Wyatt >> >> > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of > the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Question regarding leveling of vertical seismometer From: ChrisAtUpw@....... Date: Thu, 3 Apr 2008 14:19:23 EDT In a message dated 2008/04/03, charles.r.patton@........ writes: > The only other trick is to put enough weight on the base > so that the center-of-mass is within the triangle formed by the fixed > point and two screws (or use a long, triangular shaped base where all > the parts are within the triangle. Hi Charles, This is not usually done. The base is always flexible to some extent and having an offset centre of mass / anisotropic flexure may not be exactly helpful. Regards, Chris Chapman In a me= ssage dated 2008/04/03, charles.r.patton@........ writes:

The only other trick is to put=20= enough weight on the base
so that the center-of-mass is within the triangle formed by the fixed
point and two screws (or use a long, triangular shaped base where all
the parts are within the triangle.


Hi Charles,
      
       This is not usually done. The base is a= lways flexible to some extent and having an offset centre of mass / anisotro= pic flexure may not be exactly helpful.

       Regards,

       Chris Chapman Subject: Shake table From: "Kay Wyatt" kwyatt@............. Date: Fri, 4 Apr 2008 09:57:58 -0700 Folks, Thanks for the feedback on the leveling screws for my seismometer. Now here is a question regarding a shake table. =20 I currently have a small shake table that has a 10" base plate which I = use in the public schools to help kids understand the relationship of = building structure and materials to earthquake damage. I divide the = kids up into teams to construct their "buildings" and then individually = set them on the shake table. Because only one building can be tested at = a time it is more time consuming and less "fun" for the kids because = they can't easily see how their building measures up to another team's = building. So, I am constructing a larger shake table with a 30" base that can hold = four buildings. This lets a class divide up into four teams and then = the entire class can watch their buildings shake at once. Say an actual building has a footprint of 100 feet square. Relative to = a model building which has a footprint of 12 inches square, the width is = a factor of 100. I have a variable frequency motor to which I am = attaching off center cams to create the vibration movement. Springs = pull back the base towards the drive shaft with the cams. So, here is my question. Has anybody experimented with a shake table of = this size? What displacements should I design the cams to create? I = could use different size cams to create different "magnitude" = earthquakes. Also, what frequencies should I set the motor to run. Thanks for any help that you might offer. Kay
Folks,
 
Thanks for the feedback on the leveling screws = for my=20 seismometer.
 
Now here is a question regarding a shake=20 table.  
 
I currently have a small shake table that has a = 10" base=20 plate which I use in the public schools to help kids understand the = relationship=20 of building structure and materials to earthquake damage.  I divide = the=20 kids up into teams to construct their "buildings" and then individually = set them=20 on the shake table.  Because only one building can be tested at a = time it=20 is more time consuming and less "fun" for the kids because they can't = easily see=20 how their building measures up to another team's building.
 
So, I am constructing a larger shake table with = a 30" base=20 that can hold four buildings.  This lets a class divide up into = four teams=20 and then the entire class can watch their buildings shake at = once.
 
Say an actual building has a footprint of 100 = feet=20 square.  Relative to a model building which has a footprint of 12 = inches=20 square, the width is a factor of 100.  I have a variable frequency = motor to=20 which I am attaching off center cams to create the vibration = movement. =20 Springs pull back the base towards the drive shaft with the = cams.
 
So, here is my question.  Has anybody = experimented=20 with a shake table of this size?  What displacements should I = design the=20 cams to create?  I could use different size cams to create = different=20 "magnitude" earthquakes.  Also, what frequencies should I set the = motor to=20 run.
 
Thanks for any help that you might = offer.
 
Kay
 
Subject: Re: Shake table From: ChrisAtUpw@....... Date: Fri, 4 Apr 2008 15:56:19 EDT In a message dated 2008/04/04, kwyatt@............. writes: > So, I am constructing a larger shake table with a 30" base that can hold > four buildings. This lets a class divide up into four teams and then the > entire class can watch their buildings shake at once. Hi Kay, Something that size could be quite heavy. Consider foam filled buiilding / wall sheet with an Al L angle surround and four vertical foil flexures? You can also buy metal + rubber vibration isolation mountings.You can get Celotex up to at least 3" thick? This has a thin glass/resin skin. Apart from variable speed motors you can also get 'floor shakers', which are a very heavy magnet + coil driver system. We use them for testing seismometers & geophones. Alternatively, you could use a coil of wire and NdFeB magnets. Maybe drive it with a LF oscillator and an audio amplifier? The professional shake tables may use an electromagnetic drive controlled by a distance transducer. You can vary the frequency and the amplitude. Regards, Chris Chapman In a me= ssage dated 2008/04/04, kwyatt@............. writes:

So, I am constructing a larger=20= shake table with a 30" base that can hold four buildings.  This lets a=20= class divide up into four teams and then the entire class can watch their bu= ildings shake at once.


Hi Kay,

       Something that size could be quite heav= y. Consider foam filled buiilding / wall sheet with an Al L angle surround a= nd four vertical foil flexures? You can also buy metal + rubber vibration is= olation mountings.You can get Celotex up to at least 3" thick? This has a th= in glass/resin skin.
       Apart from variable speed motors you ca= n also get 'floor shakers', which are a very heavy magnet + coil driver syst= em. We use them for testing seismometers & geophones. Alternatively, you= could use a coil of wire and NdFeB magnets. Maybe drive it with a LF oscill= ator and an audio amplifier?
       The professional shake tables may use a= n electromagnetic drive controlled by a distance transducer. You can vary th= e frequency and the amplitude.

       Regards,

       Chris Chapman
 Subject: Re: Shake table From: John Lahr johnjan@........ Date: Sat, 05 Apr 2008 03:01:17 -0700 Hi Kay, This sounds like a great project. I would really like to post some pictures to my web site, along with construction details, when you're done. I've always used variable frequency, rather than amplitude. It's easier to do and let's the resonant period of the model be determined. The best frequency (the one that causes damage!) will depend on the height and construction of each model. It's best if there is a weight requirement, in that each model must carry a considerable weight on the roof. This could be considered an air conditioner unit for the building or some other machinery. One thing to avoid is providing too much time/material so that the buildings are indestructible! A teacher sent me a video of his class testing their models and they were so strong that not much happened on the shake table. One actually fell on the floor and was not damaged! Cheers, John At 09:57 AM 4/4/2008, you wrote: >Folks, > >Thanks for the feedback on the leveling screws for my seismometer. > >Now here is a question regarding a shake table. > >I currently have a small shake table that has a 10" base plate which >I use in the public schools to help kids understand the relationship >of building structure and materials to earthquake damage. I divide >the kids up into teams to construct their "buildings" and then >individually set them on the shake table. Because only one building >can be tested at a time it is more time consuming and less "fun" for >the kids because they can't easily see how their building measures >up to another team's building. > >So, I am constructing a larger shake table with a 30" base that can >hold four buildings. This lets a class divide up into four teams >and then the entire class can watch their buildings shake at once. > >Say an actual building has a footprint of 100 feet square. Relative >to a model building which has a footprint of 12 inches square, the >width is a factor of 100. I have a variable frequency motor to >which I am attaching off center cams to create the vibration >movement. Springs pull back the base towards the drive shaft with the cams. > >So, here is my question. Has anybody experimented with a shake >table of this size? What displacements should I design the cams to >create? I could use different size cams to create different >"magnitude" earthquakes. Also, what frequencies should I set the motor to run. > >Thanks for any help that you might offer. > >Kay > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Electronic components From: tchannel1@............ Date: Sat, 5 Apr 2008 09:35:15 -0600 Hi Folks, Could anyone recommend a wed site where I can purchases = electronic bits and pieces, ic's, relays, etc, and has little or no = minimum order? I did Goggle it but I am not having much luck. Thanks, Ted
Hi Folks,  Could anyone recommend = a wed site=20 where I can purchases electronic bits and pieces, ic's, = relays, etc, and=20 has little or no minimum order?
 
I did Goggle it but I am not having = much=20 luck.
 
 
Thanks, Ted
Subject: Re: Electronic components From: "Jerry Payton" gpayton880@....... Date: Sat, 5 Apr 2008 10:48:31 -0500 Hi Ted, The Mad Scientist at work again, huh. (Just joking) You might try www.mouser.com or www.digikey.com , depending upon what you are looking for. We also used http://www.allelectronics.com/ before too. Regards, Jerry ----- Original Message ----- From: tchannel1@............ To: psn Sent: Saturday, April 05, 2008 10:35 AM Subject: Electronic components Hi Folks, Could anyone recommend a wed site where I can purchases electronic bits and pieces, ic's, relays, etc, and has little or no minimum order? I did Goggle it but I am not having much luck. Thanks, Ted
Hi Ted,
 
The Mad Scientist at work again, huh.  (Just joking)
 
You might try  www.mouser.com  or  www.digikey.com , depending = upon what you=20 are looking for.  We also used  http://www.allelectronics.com/ =20 before too.
 
Regards,
Jerry
 
 
----- Original Message -----=20
From: tchannel1@............
To: psn
Sent: Saturday, April 05, 2008 10:35 AM
Subject: Electronic components

Hi Folks,  Could anyone recommend = a wed site=20 where I can purchases electronic bits and pieces, ic's, = relays, etc, and=20 has little or no minimum order?
 
I did Goggle it but I am not having = much=20 luck.
 
 
Thanks, Ted
Subject: Whip antenna From: tchannel1@............ Date: Sat, 5 Apr 2008 10:01:11 -0600 Hi Folks, If I had a 36" whip antenna, just a piece of spring steel rod, = with a small mass on the tip, how much would the tip move during a = earthquake? I know that is just a general question, and it would depend on many = factors. Let's say the size of the event was 6.0M, 1000 mile away. = This event would be recorded by all three of my sensors. The movement = of sensor's pendulum or vertical spring during this type of event would = probably not be noticeable to the eye. If the event was a large one, = then surely it would be noticeable to the eye, perhaps even 1/8" or = more. I am still trying to come up with a Earthquake Directional Device. I = have seen articles on the Chinese versions, and turn of the century = devices which used a variety of approaches, where a normal pendulum or = even a "Wipe Antenna" / inverted pendulum would be set in motion and = make contact with a circuit. I know such devices would work in = California, but I don't know how small or weak events would work. =20 My thinking is, if I just use the motion of a "Whip Antenna" to close a = contact, it would not record much, unless I could move the two points of = contact to within the thickness of a human hair. I know I could use a magnet/coil and the device would work on most all = earthquakes, presently recordable, but I don't want to dismiss these old = approaches either. Just wanted to get an opinion. Thanks, Ted
Hi Folks, If I had a 36" whip antenna, = just a piece=20 of spring steel rod, with a small mass on the tip, how much would the = tip move=20 during a earthquake?
I know that is just a general question, = and it=20 would depend on many factors.   Let's say the size of the = event was=20 6.0M, 1000 mile away.  This event would be recorded by all three of = my=20 sensors.  The movement of sensor's pendulum or vertical spring = during=20 this type of event would probably not be noticeable to the eye.  If = the=20 event was a large one, then surely it would be noticeable to the eye, = perhaps=20 even 1/8" or more.
 
I am still trying to come up with a = Earthquake=20 Directional Device.   I have seen articles on the Chinese = versions,=20 and turn of the century devices which used a variety of approaches, = where a=20 normal pendulum or even a  "Wipe Antenna" / inverted pendulum = would be=20 set in motion and make contact with a circuit.   I know such = devices=20 would work in California, but I don't know how small or weak events = would=20 work. 
 
My thinking is, if I just use the = motion of a "Whip=20 Antenna" to close a contact, it would not record much, unless I could = move the=20 two points of contact to within the thickness of a human = hair.
 
I know I could use a magnet/coil and = the device=20 would work on most all earthquakes, presently recordable, but I don't = want to=20 dismiss these old approaches either.
 
Just wanted to get an = opinion.
 
Thanks, Ted
 
Subject: Re: Electronic components From: "Erich Kern" efkern@............. Date: Sat, 5 Apr 2008 09:32:17 -0700 Ted, Send me a list (off-list, to my email adress) of what you need and I'll = email you a price quote + postage. All new parts.=20 Erich Kern Murrieta, Calif.=20 ----- Original Message -----=20 From: tchannel1@............... To: psn=20 Sent: Saturday, April 05, 2008 8:35 AM Subject: Electronic components Hi Folks, Could anyone recommend a wed site where I can purchases = electronic bits and pieces, ic's, relays, etc, and has little or no = minimum order? I did Goggle it but I am not having much luck. Thanks, Ted
 
Ted,
 
Send me a list (off-list, to my email adress) of = what you=20 need and I'll email you a price quote + postage. All new parts. =
 
Erich Kern
Murrieta, Calif.
 
 
----- Original Message -----=20
From: tchannel1@............
To: psn
Sent: Saturday, April 05, 2008 8:35 AM
Subject: Electronic components

Hi Folks,  Could anyone recommend = a wed site=20 where I can purchases electronic bits and pieces, ic's, = relays, etc, and=20 has little or no minimum order?
 
I did Goggle it but I am not having = much=20 luck.
 
 
Thanks, Ted
Subject: RE: Electronic components From: "Keith Payea" kpayea@.............. Date: Sat, 5 Apr 2008 09:35:27 -0700 Ted: Others have mentioned DigiKey and Mouser. I also use Jameco www.jameco.com for small orders. Keith _____ From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of tchannel1@............ Sent: Saturday, April 05, 2008 8:35 AM To: psn Subject: Electronic components Hi Folks, Could anyone recommend a wed site where I can purchases electronic bits and pieces, ic's, relays, etc, and has little or no minimum order? I did Goggle it but I am not having much luck. Thanks, Ted
Ted:
 
Others have mentioned DigiKey and Mouser.  = I also use=20 Jameco www.jameco.com for small=20 orders.
 
    Keith

From: psn-l-request@................. [mailto:psn-l-request@............... On Behalf Of=20 tchannel1@............
Sent: Saturday, April 05, 2008 8:35 = AM
To: psn
Subject: Electronic=20 components

Hi Folks,  Could anyone recommend = a wed site=20 where I can purchases electronic bits and pieces, ic's, = relays, etc, and=20 has little or no minimum order?
 
I did Goggle it but I am not having = much=20 luck.
 
 
Thanks, Ted
Subject: RE: Electronic components From: Brad Douglas rez@.................. Date: Sat, 05 Apr 2008 16:58:06 +0000 BTW, if you're in the SF Bay area, Jameco does will-call and walk-ins. Not everything is immediately available (different warehouse), but much of their stock is. DigiKey can be hard on shipping expenses, but they are the "gold standard". Mouser can be cheaper, but does not come close to carrying DigiKey's vast stock. Hope this helps the search for parts. On Sat, 2008-04-05 at 09:35 -0700, Keith Payea wrote: > Ted: > > Others have mentioned DigiKey and Mouser. I also use Jameco > www.jameco.com for small orders. -- 73, de Brad KB8UYR/6 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Whip antenna From: ChrisAtUpw@....... Date: Sat, 5 Apr 2008 16:20:06 EDT In a message dated 2008/04/05, tchannel1@............ writes: > Hi Folks, If I had a 36" whip antenna, just a piece of spring steel rod, > with a small mass on the tip, how much would the tip move during a earthquake? Hi Ted, The mass should ideally NOT move at all ! It is the Earth which moves. See the graphs at http://jclahr.com/science/psn/magnitude.html for actual amplitides of phases. Regards, Chris Chapman In a me= ssage dated 2008/04/05, tchannel1@............ writes:

Hi Folks, If I had a 36" whip a= ntenna, just a piece of spring steel rod, with a small mass on the tip, how=20= much would the tip move during a earthquake?


Hi Ted,

       The mass should ideally NOT move at all= ! It is the Earth which moves. See the graphs at http://jclahr.com/science/= psn/magnitude.html for actual amplitides of phases.

       Regards,

       Chris Chapman Subject: Re: Electronic components From: "Geoff" gmvoeth@........... Date: Sat, 5 Apr 2008 16:51:22 -0700 NOPE...Mad ENGINEER or Technician like ME. Did you know they do not teach law to up and coming engineers at the Universities and that those Engineers are relatively frightened of legal peoples ?? I understand in some countries if you have no degrees in the right field then practicing say like seismology might be technically illegal. I think thats why the Counter Intelligence peoples can get away with murder. They dont even know or care about the laws such as INFERNAL DEVICES. Just care about the moneys they make doing their shady work and raising their equally crooked families. I think seismology is one of the more harmless amateur sciences to be in unless it becomes somehow a real live social event. Possibly a company called Allied or Newark Electronics but its best if you can afford it to go with prebuilt systems. Complete systems unless you want to know all the technical details. The cost of parts are totally outrageous today and you almost need a microscope and surgeon tools to work with them. The EARLY 1980s saw a reduction in general industrial inventories of electronics that drove prices out of sight for little/small quantity parts. USe kits where ever possible. :-) ----- Original Message ----- From: "Jerry Payton" To: Sent: Saturday, April 05, 2008 8:48 AM Subject: Re: Electronic components > Hi Ted, > > The Mad Scientist at work again, huh. (Just joking) > > You might try www.mouser.com or www.digikey.com , depending upon what you > are looking for. We also used http://www.allelectronics.com/ before too. > > Regards, > Jerry > > > ----- Original Message ----- > From: tchannel1@............ > To: psn > Sent: Saturday, April 05, 2008 10:35 AM > Subject: Electronic components > > > Hi Folks, Could anyone recommend a wed site where I can purchases > electronic bits and pieces, ic's, relays, etc, and has little or no minimum > order? > > I did Goggle it but I am not having much luck. > > > Thanks, Ted > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Whip antenna From: "Geoff" gmvoeth@........... Date: Sat, 5 Apr 2008 17:02:21 -0700 Yesireee, The mass serves as a reference point against which the earth moves. But only frequencies at or above the point of resonance as I understand. Below resonance the mass starts to move with the Earth and more so as the frequency lowers. You must somehow lower gravity accelerational effects to the point where you get a 4 second period before you can easily fit the electronics to the sensor wuthout a lot of equalization to get a flat response ove the range of interest. Possibly 1 to 3ft/s^2 instead of 32ft/s^2 . How you do this is the real trick for a spring and a mass. :-) :-| :-O :-( ----- Original Message ----- From: To: Sent: Saturday, April 05, 2008 1:20 PM Subject: Re: Whip antenna > In a message dated 2008/04/05, tchannel1@............ writes: > >> Hi Folks, If I had a 36" whip antenna, just a piece of spring steel rod, >> with a small mass on the tip, how much would the tip move during a earthquake? > > Hi Ted, > > The mass should ideally NOT move at all ! It is the Earth which moves. > See the graphs at http://jclahr.com/science/psn/magnitude.html for actual > amplitides of phases. > > Regards, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: seismometer mass movement From: Randall Peters PETERS_RD@.......... Date: Mon, 07 Apr 2008 09:41:42 -0400 Geoff, Your understanding is indeed correct. Only for drive frequencies above the natural frequency of the instrument does the mass not move relative to the inertial frame (instrument behaving as a vibrometer). At frequencies below the natural frequency, it is the motion of the mass relative to the inertial frame that limits sensitivity. By making the natural frequency lower, the amplitude of this mass motion decreases, which increases the sensitivity (and is the reason for the low frequency sensitivity to displacement being proportional to the square of the natural period). At very low drive frequency the pendulum aligns itself with the vector sum of the earth's field vector g and the negative of the drive acceleration vector a; i.e., the angle of deflection in radians is given by -a/g (for a small compared to g). If there were no mass motion at low drive frequency, the pendulum would have no acceleration response whatsoever. Instead of the small deflection angle in radians being -a/g, zero inertial mass motion would require the angle to be identically zero. One can demonstrate the difference between high frequency stationary mass and low frequency moving mass very easily with a simple pendulum (a nut and a string). Hold the pendulum with your hand at the top of the string supporting the nut on the other end. Move your hand rapidly back and forth and you will see that the bob doesn't move--being at rest with respect to the room but with a motion relative to your hand that is out of phase by 180 degrees. Now move the string back and forth slowly and you will see the bob is in phase (in a relative sense) with your hand's motion (and it most certainly is not at rest relative to the room). Randall Subject: correction--mass movement From: Randall Peters PETERS_RD@.......... Date: Mon, 07 Apr 2008 09:58:23 -0400 If the mass did not move at very low drive frequencies, the deflection would be non-physically huge instead of my statement that is would be zero. Subject: RE: Shake table From: felipe luevanos luevanos felicaribe5@........... Date: Mon, 7 Apr 2008 20:17:40 +0000 Hi, =20 =20 What you are building is nice; have you tried having inverted pendulums sup= ported by a 2x4 piece of wood all of the pendulums in different lengths wit= h lets say foam balls of equal or different masses, then you shake the tabl= e with your hands at diffrent frequencies and observe the totally different= responses of each (ball/mass/pendulum)? =20 Good luck =20 =20 Felipe Luevanos From: kwyatt@................ psn-l@...................... Shake tableDate:= Fri, 4 Apr 2008 09:57:58 -0700 Folks, =20 Thanks for the feedback on the leveling screws for my seismometer. =20 Now here is a question regarding a shake table. =20 =20 I currently have a small shake table that has a 10" base plate which I use = in the public schools to help kids understand the relationship of building = structure and materials to earthquake damage. I divide the kids up into te= ams to construct their "buildings" and then individually set them on the sh= ake table. Because only one building can be tested at a time it is more ti= me consuming and less "fun" for the kids because they can't easily see how = their building measures up to another team's building. =20 So, I am constructing a larger shake table with a 30" base that can hold fo= ur buildings. This lets a class divide up into four teams and then the ent= ire class can watch their buildings shake at once. =20 Say an actual building has a footprint of 100 feet square. Relative to a m= odel building which has a footprint of 12 inches square, the width is a fac= tor of 100. I have a variable frequency motor to which I am attaching off = center cams to create the vibration movement. Springs pull back the base t= owards the drive shaft with the cams. =20 So, here is my question. Has anybody experimented with a shake table of th= is size? What displacements should I design the cams to create? I could u= se different size cams to create different "magnitude" earthquakes. Also, = what frequencies should I set the motor to run. =20 Thanks for any help that you might offer. =20 Kay =20 _________________________________________________________________ Connect to the next generation of MSN Messenger=A0 http://imagine-msn.com/messenger/launch80/default.aspx?locale=3Den-us&sourc= e=3Dwlmailtagline= Hi,
 
 
What you are building is nice; have you tried having inverted pendulums sup= ported by a 2x4 piece of wood all of the pendulums in different lengths wit= h lets say foam balls of equal or different masses, then you shake the tabl= e with your hands at diffrent frequencies and observe the totally different= responses of each (ball/mass/pendulum)?
 
Good luck
 
 
Felipe Luevanos


From: kwyatt@.............
To: psn-l@..............
Subject: Shake ta= ble
Date: Fri, 4 Apr 2008 09:57:58 -0700

Folks,
 
Thanks for the feedback on the leveling screws for = my seismometer.
 
Now here is a question regarding a shake table.&nbs= p; 
 
I currently have a small shake table that has a 10"= base plate which I use in the public schools to help kids understand the r= elationship of building structure and materials to earthquake damage. = I divide the kids up into teams to construct their "buildings" and then in= dividually set them on the shake table.  Because only one building can= be tested at a time it is more time consuming and less "fun" for the kids = because they can't easily see how their building measures up to another tea= m's building.
 
So, I am constructing a larger shake table with a 3= 0" base that can hold four buildings.  This lets a class divide up int= o four teams and then the entire class can watch their buildings shake at o= nce.
 
Say an actual building has a footprint of 100 feet = square.  Relative to a model building which has a footprint of 12 inch= es square, the width is a factor of 100.  I have a variable frequency = motor to which I am attaching off center cams to create the vibration movem= ent.  Springs pull back the base towards the drive shaft with the cams= ..
 
So, here is my question.  Has anybody experime= nted with a shake table of this size?  What displacements should I des= ign the cams to create?  I could use different size cams to create dif= ferent "magnitude" earthquakes.  Also, what frequencies should I set t= he motor to run.
 
Thanks for any help that you might offer.
 
Kay
 

Connect to the next generation of= MSN Messenger=A0 Get it now= ! = Subject: Re: Shake table From: ChrisAtUpw@....... Date: Mon, 7 Apr 2008 18:23:23 EDT In a message dated 2008/04/07, felicaribe5@........... writes: > What you are building is nice; have you tried having inverted pendulums > supported by a 2x4 piece of wood all of the pendulums in different lengths with > lets say foam balls of equal or different masses, then you shake the table > with your hands at diffrent frequencies and observe the totally different > responses of each (ball/mass/pendulum)? Hi Felipe, This works fine as a simple demonstration, but it doesn't capture the attention of students the way that having them build four model 'buildings' and then see them collapse in sequence can. Most students will not think of a real tall building as something which can and does oscillate and fall to pieces during an Earthquake. Regards, Chris Chapman In a me= ssage dated 2008/04/07, felicaribe5@........... writes:

What you are building is nice;=20= have you tried having inverted pendulums supported by a 2x4 piece of wood al= l of the pendulums in different lengths with lets say foam balls of equal or= different masses, then you shake the table with your hands at diffrent freq= uencies and observe the totally different responses of each (ball/mass/pendu= lum)?


Hi Felipe,

       This works fine as a simple demonstrati= on, but it doesn't capture the attention of students the way that having the= m build four model 'buildings' and then see them collapse in sequence can. <= BR>        Most students will not think of a real=20= tall building as something which can and does oscillate and fall to pieces d= uring an Earthquake.

       Regards,

       Chris Chapman Subject: Article On Microseisms From: Bob Hancock carpediem1@......... Date: Thu, 10 Apr 2008 19:32:06 -0700 The link is to an article on microseisms http://earthobservatory.nasa.gov/Newsroom/NasaNews/2008/2008030726263.html Article On Microseisms The l= ink is to an article on microseisms


    http://earthobservatory.nasa.gov/Newsro= om/NasaNews/2008/2008030726263.html
 


 Subject: Re: Article On Microseisms From: "Geoff" gmvoeth@........... Date: Fri, 11 Apr 2008 05:29:47 -0700 Interesting, I have noticed a significant increase in the magnitude of such Microseisms just hours preceeding a major weather front here in Arizona. I used to think it might relate to winds hitting the mountains but according to this it must be wave interaction in the Pacific Ocean. ----- Original Message ----- From: "Bob Hancock" To: "PSN" Sent: Thursday, April 10, 2008 7:32 PM Subject: Article On Microseisms > The link is to an article on microseisms > > > > http://earthobservatory.nasa.gov/Newsroom/NasaNews/2008/2008030726263.html > > > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Article On Microseisms From: ChrisAtUpw@....... Date: Fri, 11 Apr 2008 09:46:11 EDT In a message dated 2008/04/11, gmvoeth@........... writes: > I have noticed a significant increase in the magnitude of such Microseisms > just hours preceeding a major weather front here in Arizona. > I used to think it might relate to winds hitting the mountains but according > to this it must be wave interaction in the Pacific Ocean. Hi Geoff, Those were probably due to pressure noise on the weather front. They can be quite noisy. Note that there are several places in the ocean which generate microseisms. The news article referreed to only one. The shelving bottom to the west of Norway is another and there are others in the Pacific. Regards, Chris Chapman In a me= ssage dated 2008/04/11, gmvoeth@........... writes:

I have noticed a significant in= crease in the magnitude of such Microseisms
just hours preceeding a major weather front here in Arizona.
I used to think it might relate to winds hitting the mountains but according= to this it must be wave interaction in the Pacific Ocean.


Hi Geoff,

       Those were probably due to pressure noi= se on the weather front. They can be quite noisy.

       Note that there are several places in t= he ocean which generate microseisms. The news article referreed to only one.= The shelving bottom to the west of Norway is another and there are others i= n the Pacific.

       Regards,

       Chris Chapman Subject: Re: Article On Microseisms From: Bob Hancock carpediem1@......... Date: Fri, 11 Apr 2008 07:12:12 -0700 Hi Chris - As you said, microseisms are generated world wide when ocean waves strike shore. The strength of the microseisms are largely dependent upon the size of the waves that come ashore. The US Navy Fleet Numerical Meteorology and Oceanography Center - https://www.fnmoc.navy.mil/public/ publishes charts with current and projected ocean wave height worldwide and regional. This web site is a good place to start with when you see microseisms. You can often see the microseisms from large oceanic storms at long distances. East Coast USA hurricanes are very visible on West Coast USA seismic stations, and are probably also visible in Europe. Cheers, Bob Hancock On 4/11/08 6:46 AM, "ChrisAtUpw@......." wrote: > In a message dated 2008/04/11, gmvoeth@........... writes: > >> I have noticed a significant increase in the magnitude of such Microseisms >> just hours preceeding a major weather front here in Arizona. >> I used to think it might relate to winds hitting the mountains but according >> to this it must be wave interaction in the Pacific Ocean. > > > Hi Geoff, > > Those were probably due to pressure noise on the weather front. They > can be quite noisy. > > Note that there are several places in the ocean which generate > microseisms. The news article referreed to only one. The shelving bottom to > the west of Norway is another and there are others in the Pacific. > > Regards, > > Chris Chapman Re: Article On Microseisms Hi Ch= ris -

As you said, microseisms are generated world wide when ocean waves strike s= hore.  The strength of the microseisms are largely dependent upon the s= ize of the waves that come ashore.

The US Navy Fleet Numerical Meteorology and Oceanography Center -  htt= ps://www.fnmoc.navy.mil/public/

publishes charts with current and projected ocean wave height worldwide and= regional.  This web site is a good place to start with when you see mi= croseisms.  You can often see the microseisms from large oceanic storms= at long distances.  East Coast USA hurricanes are very visible on West= Coast USA seismic stations, and are probably also visible in Europe.

Cheers,

Bob Hancock

On 4/11/08 6:46 AM, "ChrisAtUpw@......." <ChrisAtUpw@.......&g= t; wrote:

In a message dated 2008/04/11, gmvoeth@........... writes:

I have noticed a significant increase in the magnitude of such Microseisms<= BR> just hours preceeding a major weather front here in Arizona.
I used to think it might relate to winds hitting the mountains but accordin= g to this it must be wave interaction in the Pacific Ocean.


Hi Geoff,

       Those were probably due to pressu= re noise on the weather front. They can be quite noisy.

       Note that there are several place= s in the ocean which generate microseisms. The news article referreed to onl= y one. The shelving bottom to the west of Norway is another and there are ot= hers in the Pacific.

       Regards,

       Chris Chapman   

 Subject: Re: Article On Microseisms From: ChrisAtUpw@....... Date: Fri, 11 Apr 2008 11:06:28 EDT In a message dated 2008/04/11, carpediem1@......... writes: > As you said, microseisms are generated world wide when ocean waves strike > shore. The strength of the microseisms are largely dependent upon the size of > the waves that come ashore. Hi Bob, Not generally I think. There is an ocean area S of Greenland and another on the continental shelf off the NW coast of Norway which dominate the Atlantic systems. You can also get 10 to 12 second stuff from storms directly coming on shore, but that is different. Cold fronts can also have a lot of seismic noise on them, as Geoff observed. Regards, Chris Chapman In a message dated 2008/04/11, carp= ediem1@......... writes:

As you said, microseisms are= generated world wide when ocean waves strike shore.  The strength of t= he microseisms are largely dependent upon the size of the waves that come as= hore.


Hi Bob,

       Not generally I think. There is an ocea= n area S of Greenland and another on the continental shelf off the NW coast=20= of Norway which dominate the Atlantic systems. You can also get 10 to 12 sec= ond stuff from storms directly coming on shore, but that is different.
       Cold fronts can also have a lot of seis= mic noise on them, as Geoff observed.

       Regards,

       Chris Chapman Subject: Re: Article On Microseisms From: Bob Hancock carpediem1@......... Date: Fri, 11 Apr 2008 09:02:47 -0700 Hi Chris - Cold fronts can generate increased wind velocity. This in turn moves trees and buildings, and this is visible on seismometers; however, this does not appear to travel long distances. This is readily visible on the seismometers located in the Long Valley Caldera, Mammoth Lakes, CA, an area subject to high winds. However, ocean storms, particularly when they come ashore can increase seismic background noise that travels for thousands of kilometers. This is observable when major storms or hurricanes and typhoons occur. In addition, low frequency background seismic noise is more pronounced on seismic stations located on small islands =AD such as Pitcairn Island, Wake Island, and many others all around the world. This is at a much lower frequency than is normally associated with microseisms , and I do not know if would be classified as a microseism. Cheers Bob Hancock =20 On 4/11/08 8:06 AM, "ChrisAtUpw@......." wrote: > In a message dated 2008/04/11, carpediem1@......... writes: >=20 >> As you said, microseisms are generated world wide when ocean waves strik= e >> shore. The strength of the microseisms are largely dependent upon the s= ize >> of the waves that come ashore. >=20 >=20 > Hi Bob, >=20 > Not generally I think. There is an ocean area S of Greenland and > another on the continental shelf off the NW coast of Norway which dominat= e the > Atlantic systems. You can also get 10 to 12 second stuff from storms dire= ctly > coming on shore, but that is different. > Cold fronts can also have a lot of seismic noise on them, as Geoff > observed. >=20 > Regards, >=20 > Chris Chapman Re: Article On Microseisms Hi Ch= ris -

Cold fronts can generate increased wind velocity.  This in turn moves = trees and buildings, and this is visible on seismometers; however, this does= not appear to travel long distances.  This is readily visible on the s= eismometers located in the Long Valley Caldera, Mammoth Lakes, CA, an area s= ubject to high winds.

However, ocean storms, particularly when they come ashore can increase seis= mic background noise that travels for thousands of kilometers.  This is= observable when major storms or hurricanes and typhoons occur.

In addition, low frequency background seismic noise is more pronounced on s= eismic stations located on small islands – such as Pitcairn Island, Wa= ke Island, and many others all around the world.  This is at a much low= er frequency than is normally associated with microseisms , and I do not kno= w if would be classified as a microseism.

Cheers

Bob Hancock

  


On 4/11/08 8:06 AM, "ChrisAtUpw@......." <ChrisAtUpw@.......&g= t; wrote:

In a message dated 2008/04/11, carpediem1@......... writes:

As you said, microseisms are generated world wide when = ocean waves strike shore.  The strength of the microseisms are largely = dependent upon the size of the waves that come ashore.


Hi Bob,

       Not generally I think. There is a= n ocean area S of Greenland and another on the continental shelf off the NW = coast of Norway which dominate the Atlantic systems. You can also get 10 to = 12 second stuff from storms directly coming on shore, but that is different.=
       Cold fronts can also have a lot o= f seismic noise on them, as Geoff observed.

       Regards,

       Chris Chapman   

 Subject: Noise From: "Thomas Dick" dickthomas01@............. Date: Sat, 12 Apr 2008 21:45:03 -0500 I have never been satisfied with my setup. I would like some suggestions = on where to look for the noise I still get on my units. Among the things = that I have enjoyed identifying included wind, walnuts falling on the = porch roof, a microwave oven, garbage trucks(empty and full), falling = trees, an assortment of caterpillars and shovels moving dirt and a = seismic truck testing soils in my area for liquifaction. If anybody has = the time, I put a rather large PDF file (~2.5 megs) on this site = http://bachcottage.com/inquiry.pdf. My eventual goal is to get to the = level of the rest of the PSN event submissions. Your suggestions would = be welcomed.
I have never been satisfied with my = setup. I would=20 like some suggestions on where to look for the noise I still get on = my=20 units. Among the things that I have enjoyed identifying included wind, = walnuts=20 falling on the porch roof, a microwave oven, garbage trucks(empty and = full),=20 falling trees, an assortment of caterpillars and shovels moving = dirt and a=20 seismic truck testing soils in my area for liquifaction. If anybody = has the=20 time, I put a rather large PDF file (~2.5 megs) on this site http://bachcottage.com/inquiry.pdf. My eventual goal = is to get=20 to the level of the rest of the PSN event submissions. Your suggestions = would be=20 welcomed.
Subject: Re:Noise From: rsparks rsparks@.......... Date: Sun, 13 Apr 2008 06:26:26 -0700 Hi Dick, I took a look at your posting. Nice job of collecting information and posting. For reference, I collected one hours noise from this morning. http://www.fairpoint.net/~rsparks/080413_090338_ebgz_psn_fft.gif My seismometer is a tilted vertical with a single long spring supporting the sensing coil. The spring is the hinge. I post under the station identifier "EBGZ". The seismometer is in the basement. From looking at your pictures and FFT, I wondered if all of your components are either securely assembled or placed on three point mounts. Four point mounts or components resting on flat surfaces can be unexpected balanced between two semi-stable positions. If so, the microsiems or quakes can move the components between those two positions resulting in high frequency noise. Another source of noise can be the hinges. The AS-1 actually has three hinges if you count the spring attachment points as moving connections. I don't know if lubrication with a light oil would help or not. The problem from hinges is that all hinges have some friction, and the motion in a seismometer hinge starts and stops. Static friction is always greater than moving friction so there is a small "tremble" as the transfer between static and moving occurs. This "tremble" would be recorded as noise. You could test the electronic noise by locking the seismometer. I would not expect much noise from electronics compared to the noise that will come from the seismometer output. Certainly the wind can cause noise but you are probably well aware of the magnitude of wind and other locally generated noise sources. Good luck on your noise hunt. Roger > .------ ------ ------ ------ ------ ------ ------ ------ ------ ------. > | Message 1 | > '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' > Subject: Noise > From: "Thomas Dick" > Date: Sat, 12 Apr 2008 21:45:03 -0500 > > > I have never been satisfied with my setup. I would like some suggestions = > on where to look for the noise I still get on my units. Among the things = > that I have enjoyed identifying included wind, walnuts falling on the = > porch roof, a microwave oven, garbage trucks(empty and full), falling = > trees, an assortment of caterpillars and shovels moving dirt and a = > seismic truck testing soils in my area for liquifaction. If anybody has = > the time, I put a rather large PDF file (~2.5 megs) on this site = > http://bachcottage.com/inquiry.pdf. My eventual goal is to get to the = > level of the rest of the PSN event submissions. Your suggestions would = > be welcomed. > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Re:Noise From: "Thomas Dick" dickthomas01@............. Date: Sun, 13 Apr 2008 12:30:44 -0500 From looking at your pictures and FFT, I wondered if all of your components are either securely assembled or placed on three point mounts Four point mounts or components resting on flat surfaces can be unexpected balanced between two semi-stable positions. I did use four pivot points on the Lehmans...a mistake I won't make again .... the bases for the Lehmans are 1/4" steel these could be used as boat anchors ... unfortunately I sold the boat! The support of the mental plates that hold the magnets isn't as stable ... this could be an issue. But the peaks at 4 hz is gound on the geophone buried outside! If so, the microsiems or quakes can move the components between those two positions resulting in high frequency noise .. The AS-1 uses a knief edge rather than a hinge. The AS-1 sits in an old refrigerator with the door closed. The pivot point on the booms of the Lehmans is a stainless steel ball bearing. The only issue I haven't addressed is that the Lehmans sit on concrete blocks sitting on the concrete floor. From what you infer, this might be an issue. I raised the Lehmans up off the floor so that I didn't have to bend over as much. . I collected one hours noise from this morning. Mine are one minute but it would help know where you two are....??? Georgia??? Macon ...right? You could test the electronic noise by locking the seismometer. I would not expect much noise from electronics compared to the noise that will come from the seismometer output. suggestion under advisement This issue has been around for some time. I even sent one amp board back to Larry for him to look at. I put an isolation transformer and battery back up to help smooth out the AC. I even had the local electric company come out(firends in the right places) with special equipment and test the incoming AC...nothing serious there. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Noise From: "Dale Hardy" photon1@........... Date: Mon, 14 Apr 2008 11:51:52 +1000 Hi Thomas, tried to open the site in IE7 and Firefox unsucessfully, is = the link correct ? thanks Dale ----- Original Message -----=20 From: Thomas Dick=20 To: psn-l@................. Sent: Sunday, April 13, 2008 12:45 PM Subject: Noise I have never been satisfied with my setup. I would like some = suggestions on where to look for the noise I still get on my units. = Among the things that I have enjoyed identifying included wind, walnuts = falling on the porch roof, a microwave oven, garbage trucks(empty and = full), falling trees, an assortment of caterpillars and shovels moving = dirt and a seismic truck testing soils in my area for liquifaction. If = anybody has the time, I put a rather large PDF file (~2.5 megs) on this = site http://bachcottage.com/inquiry.pdf. My eventual goal is to get to = the level of the rest of the PSN event submissions. Your suggestions = would be welcomed.
Hi Thomas, tried to open the site in = IE7 and=20 Firefox unsucessfully, is the link correct ?
thanks
Dale
----- Original Message -----
From:=20 Thomas Dick
Sent: Sunday, April 13, 2008 = 12:45=20 PM
Subject: Noise

I have never been satisfied with my = setup. I=20 would like some suggestions on where to look for the noise I = still get on=20 my units. Among the things that I have enjoyed identifying included = wind,=20 walnuts falling on the porch roof, a microwave oven, garbage = trucks(empty and=20 full), falling trees, an assortment of caterpillars and shovels moving = dirt and a seismic truck testing soils in my area for = liquifaction.=20 If anybody has the time, I put a rather large PDF file (~2.5 megs) on = this=20 site http://bachcottage.com/inquiry.pdf. My eventual = goal is to=20 get to the level of the rest of the PSN event submissions. Your = suggestions=20 would be welcomed.
Subject: Re: Noise From: "Thomas Dick" dickthomas01@............. Date: Sun, 13 Apr 2008 21:15:56 -0500 yes, it might be a little slow particularly in the PDF format....sorry ----- Original Message -----=20 From: Dale Hardy=20 To: psn-l@................. Sent: Sunday, April 13, 2008 8:51 PM Subject: Re: Noise Hi Thomas, tried to open the site in IE7 and Firefox unsucessfully, is = the link correct ? thanks Dale ----- Original Message -----=20 From: Thomas Dick=20 To: psn-l@................. Sent: Sunday, April 13, 2008 12:45 PM Subject: Noise I have never been satisfied with my setup. I would like some = suggestions on where to look for the noise I still get on my units. = Among the things that I have enjoyed identifying included wind, walnuts = falling on the porch roof, a microwave oven, garbage trucks(empty and = full), falling trees, an assortment of caterpillars and shovels moving = dirt and a seismic truck testing soils in my area for liquifaction. If = anybody has the time, I put a rather large PDF file (~2.5 megs) on this = site http://bachcottage.com/inquiry.pdf. My eventual goal is to get to = the level of the rest of the PSN event submissions. Your suggestions = would be welcomed.
yes, it might be a little slow = particularly in the=20 PDF format....sorry
----- Original Message -----
From:=20 Dale Hardy=20
Sent: Sunday, April 13, 2008 = 8:51=20 PM
Subject: Re: Noise

Hi Thomas, tried to open the site in = IE7 and=20 Firefox unsucessfully, is the link correct ?
thanks
Dale
----- Original Message -----
From:=20 Thomas Dick
Sent: Sunday, April 13, 2008 = 12:45=20 PM
Subject: Noise

I have never been satisfied with my = setup. I=20 would like some suggestions on where to look for the noise I = still get=20 on my units. Among the things that I have enjoyed identifying = included wind,=20 walnuts falling on the porch roof, a microwave oven, garbage = trucks(empty=20 and full), falling trees, an assortment of caterpillars and shovels = moving=20 dirt and a seismic truck testing soils in my area for=20 liquifaction. If anybody has the time, I put a rather large PDF file = (~2.5=20 megs) on this site http://bachcottage.com/inquiry.pdf.=20 My eventual goal is to get to the level of the rest of the PSN event = submissions. Your suggestions would be=20 welcomed.
Subject: Re: Noise From: pattilightfoot11@....... Date: Sun, 13 Apr 2008 23:38:55 -0400 Hello, Could you please remove my name from your emailing. I just wanted info if there was anything to be concerned about! Thanks! Patti -----Original Message----- From: Dale Hardy To: psn-l@.............. Sent: Sun, 13 Apr 2008 6:51 pm Subject: Re: Noise Hi Thomas, tried to open the site in IE7 and Firefox unsucessfully, is the link correct ? thanks Dale ----- Original Message ----- From: Thomas Dick To: psn-l@.............. Sent: Sunday, April 13, 2008 12:45 PM Subject: Noise I have never been satisfied with my setup. I would like some suggestions on where to look for?the noise I still get on my units. Among the things that I have enjoyed identifying included wind, walnuts falling on the porch roof, a microwave oven, garbage trucks(empty and full), falling trees, an assortment of caterpillars and shovels moving dirt?and a seismic truck testing soils in?my area for liquifaction. If anybody has the time, I put a rather large PDF file (~2.5 megs) on this site http://bachcottage.com/inquiry.pdf. My eventual goal is to get to the level of the rest of the PSN event submissions. Your suggestions would be welcomed. Hello, Could you please remove my name from your emailing. I just wanted info if there was anything to be concerned about!

Thanks!

Patti



-----Original Message-----
From: Dale Hardy <photon1@...........>
To: psn-l@..............
Sent: Sun, 13 Apr 2008 6:51 pm
Subject: Re: Noise

Hi Thomas, tried to open the site in IE7 and Firefox unsucessfully, is the link correct ?
thanks
Dale
----- Original Message -----
Sent: Sunday, April 13, 2008 12:45 PM
Subject: Noise

I have never been satisfied with my setup. I would like some suggestions on where to look for the noise I still get on my units. Among the things that I have enjoyed identifying included wind, walnuts falling on the porch roof, a microwave oven, garbage trucks(empty and full), falling trees, an assortment of caterpillars and shovels moving dirt and a seismic truck testing soils in my area for liquifaction. If anybody has the time, I put a rather large PDF file (~2.5 megs) on this site http://bachcottage.com/inquiry.pdf. My eventual goal is to get to the level of the rest of the PSN event submissions. Your suggestions would be welcomed.
Subject: Re: Noise From: pattilightfoot11@....... Date: Sun, 13 Apr 2008 23:39:11 -0400 Hello, Could you please remove my name from your emailing. I just wanted info if there was anything to be concerned about! Thanks! Patti -----Original Message----- From: Thomas Dick To: psn-l@.............. Sent: Sun, 13 Apr 2008 7:15 pm Subject: Re: Noise yes, it might be a little slow particularly in the PDF format....sorry ----- Original Message ----- From: Dale Hardy To: psn-l@.............. Sent: Sunday, April 13, 2008 8:51 PM Subject: Re: Noise Hi Thomas, tried to open the site in IE7 and Firefox unsucessfully, is the link correct ? thanks Dale ----- Original Message ----- From: Thomas Dick To: psn-l@.............. Sent: Sunday, April 13, 2008 12:45 PM Subject: Noise I have never been satisfied with my setup. I would like some suggestions on where to look for?the noise I still get on my units. Among the things that I have enjoyed identifying included wind, walnuts falling on the porch roof, a microwave oven, garbage trucks(empty and full), falling trees, an assortment of caterpillars and shovels moving dirt?and a seismic truck testing soils in?my area for liquifaction. If anybody has the time, I put a rather large PDF file (~2.5 megs) on this site http://bachcottage.com/inquiry.pdf. My eventual goal is to get to the level of the rest of the PSN event submissions. Your suggestions would be welcomed. Hello, Could you please remove my name from your emailing. I just wanted info if there was anything to be concerned about!

Thanks!

Patti


-----Original Message-----
From: Thomas Dick <dickthomas01@.............>
To: psn-l@..............
Sent: Sun, 13 Apr 2008 7:15 pm
Subject: Re: Noise

yes, it might be a little slow particularly in the PDF format....sorry
----- Original Message -----
From: Dale Hardy
Sent: Sunday, April 13, 2008 8:51 PM
Subject: Re: Noise

Hi Thomas, tried to open the site in IE7 and Firefox unsucessfully, is the link correct ?
thanks
Dale
----- Original Message -----
Sent: Sunday, April 13, 2008 12:45 PM
Subject: Noise

I have never been satisfied with my setup. I would like some suggestions on where to look for the noise I still get on my units. Among the things that I have enjoyed identifying included wind, walnuts falling on the porch roof, a microwave oven, garbage trucks(empty and full), falling trees, an assortment of caterpillars and shovels moving dirt and a seismic truck testing soils in my area for liquifaction. If anybody has the time, I put a rather large PDF file (~2.5 megs) on this site http://bachcottage.com/inquiry.pdf. My eventual goal is to get to the level of the rest of the PSN event submissions. Your suggestions would be welcomed.
Subject: Re: Noise From: ChrisAtUpw@....... Date: Mon, 14 Apr 2008 00:03:35 EDT In a message dated 2008/04/14, pattilightfoot11@....... writes: > Could you please remove my name from your emailing. Hi Patti, Go to http://psn.quake.net/maillist.html#archives, fill in the form and click the unsubscribe dot. Regards, Chris In a me= ssage dated 2008/04/14, pattilightfoot11@....... writes:

Could you please remove my name= from your emailing.


Hi Patti,

       Go to http://psn.quake.net/maillist.htm= l#archives, fill in the form and click the unsubscribe dot.

       Regards,
      
       Chris Subject: Oregon earthquake swarm From: jonfr@......... Date: Mon, 14 Apr 2008 21:52:43 -0400 (EDT) Hi all Here are news regarding the Oregon earthquakes. The data so far suggests that there might be an eruption happening in that area. If any of you that are close to this area detect low frequancy signal that is not earthquake you might be looking at eruption tremor that is constant. http://www.sciencedaily.com/releases/2008/04/080413184801.htm http://www.ecanadanow.com/news/science/string-of-strange-earthquakes-rock-oregon-20080414.html Regards. Jón Frímann. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Oregon earthquake swarm From: "Thomas Dick" dickthomas01@............. Date: Mon, 14 Apr 2008 21:19:29 -0500 NBC New tonight on this subject http://www.nbc15online.com/news/national/story.aspx?content_id=5b190a5f-b113-46ac-9f6b-4d8df90f4587 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Oregon earthquake swarm From: "Geoff" gmvoeth@........... Date: Mon, 14 Apr 2008 22:31:46 -0700 I think there are black smokers of volcanic origin in that area and when I was a SONAR tech aboard the USS Bainbridge back in the mid-late 1970s I saw a contact on the TBR (Time Bearing Recorder) that was weak and continuous and was not able to identify that seemed to be coming from that area of the Pacific Ocean. Today it would not surprise me if that contact had been one of those smoker thingys really putting on a show. I pointed the ship right at the contact to try and get closer and louder but the navagational people got upset with me and I turned control back to them so we could all go home. A steady black smoker volcanic thingy would explain the kind of noise I saw but was unable to hear. It was off central Oregon about 280 290 degrees or so as we were headed for the Straights of Juan De Fuca If I remember correctly. The Navagational logs of the ship should have recorded the position and course change of the ship and the ship was pointed by myself directly at the noise source for a few minutes. It was far enough away that the bearing did not change very much as we traveled on and simply lost interest in the target. But also i heard that a Soviet Nuclear Sub liked to do a slow three knot circle in that same area. 100 miles or so off the Coast of Oregon. :-( So you tell me what i saw ??? ----- Original Message ----- From: To: Sent: Monday, April 14, 2008 6:52 PM Subject: Oregon earthquake swarm > Hi all > > Here are news regarding the Oregon earthquakes. The data so far suggests > that there might be an eruption happening in that area. If any of you that > are close to this area detect low frequancy signal that is not earthquake > you might be looking at eruption tremor that is constant. > > http://www.sciencedaily.com/releases/2008/04/080413184801.htm > http://www.ecanadanow.com/news/science/string-of-strange-earthquakes-rock-oregon-20080414.html > > Regards. > Jón Frímann. > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Katla volcano preparing eruption From: jonfr@......... Date: Tue, 15 Apr 2008 17:19:40 -0400 (EDT) Hi all It appears that Katla volcano is preparing an eruption. On the 8th April there was a 10 min long tremor detected in the volcano. One of the main glacier rivers from the Myrdalsjokull glacier has been dry since mid January. So the evidence for an coming eruption are mounting. The tremor can be seen here. http://hraun.vedur.is/ja/viku/2008/vika_15/katla.jpg I am going to setup a geophone near Hekla volcano in June, so if there is going to be an eruption in Katla it is going to appear good on that station too. I've post new information on this when I know more. Regards. Jón Frímann. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: quake From: "Thomas Dick" dickthomas01@............. Date: Fri, 18 Apr 2008 04:50:01 -0500 I don't know where but we just had a serious quake here in Evansville = In. Can't get out to some of the networks. It woke me. Lasted for almost = a minute or more. Can anyone tell me where it was?
I don't know where but we just had a = serious quake=20 here in Evansville In. Can't get out to some of the networks. It woke = me. Lasted=20 for almost a minute or more. Can anyone tell me where it = was?
 
Subject: Re: quake From: "Robert Thomasson" rlthomasson@......... Date: Fri, 18 Apr 2008 13:00:25 +0300 It was a magnitude 5.4 about 7 miles from West Salem, Illinois. I picked it up very nicely here in Reno. On Fri, Apr 18, 2008 at 12:50 PM, Thomas Dick wrote: > I don't know where but we just had a serious quake here in Evansville In. > Can't get out to some of the networks. It woke me. Lasted for almost a > minute or more. Can anyone tell me where it was? > > It was a magnitude 5.4 about 7 miles from West Salem, Illinois.  I picked it up very nicely here in Reno.

On Fri, Apr 18, 2008 at 12:50 PM, Thomas Dick <dickthomas01@.............> wrote:
I don't know where but we just had a serious quake here in Evansville In. Can't get out to some of the networks. It woke me. Lasted for almost a minute or more. Can anyone tell me where it was?
 

Subject: Re: quake From: jonfr@......... Date: Fri, 18 Apr 2008 06:05:01 -0400 (EDT) Hi EMSC is reporting Mb5.4 earthquake in Illinois at the depth of 2 km. More details here, http://www.emsc-csem.org/index.php?page=current&sub=detail&id=83987 Regards. Jón Frímann. > It was a magnitude 5.4 about 7 miles from West Salem, Illinois. I picked > it > up very nicely here in Reno. > > On Fri, Apr 18, 2008 at 12:50 PM, Thomas Dick > wrote: > >> I don't know where but we just had a serious quake here in Evansville >> In. >> Can't get out to some of the networks. It woke me. Lasted for almost a >> minute or more. Can anyone tell me where it was? >> >> > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: Mark Robinson mark.robinson@............... Date: Fri, 18 Apr 2008 22:06:29 +1200 Thomas Dick wrote: > > I don't know where but we just had a serious quake here in Evansville > In. Can't get out to some of the networks. It woke me. Lasted for almost > a minute or more. Can anyone tell me where it was? http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008qza6.php 5.4, Illinois -- Mark Robinson ------------- 18 Apr 1906 5am San Francisco devastated by earthquake and ensuing fire. 400 killed. 18 Apr 1954 Nasser becomes Egyptian Premier. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: quake From: "Finke, John" John.Finke@.......... Date: Fri, 18 Apr 2008 05:04:24 -0500 Good thing for the PSN, the EQ woke my whole family and they asked me if = it was an earthquake but I too was unable to get to any networks. Hence rig= ht now, with your response, is the only confirmation we have of it in the Midwest. Earthquake watch.com doesn't even show it. ________________________________ From: psn-l-request@.............. on behalf of Robert Thomasson Sent: Fri 4/18/2008 5:00 AM To: psn-l@.............. Subject: Re: quake It was a magnitude 5.4 about 7 miles from West Salem, Illinois. I picked= it up very nicely here in Reno. On Fri, Apr 18, 2008 at 12:50 PM, Thomas Dick wrote: I don't know where but we just had a serious quake here in Evansville In. Can't get out to some of the networks. It woke me. Lasted for almost = a minute or more. Can anyone tell me where it was? =20 NOTICE - This communication may contain confidential and privileged infor= mation that is for the sole use of the intended recipient. Any viewing, c= opying or distribution of, or reliance on this message by unintended reci= pients is strictly prohibited. If you have received this message in error= , please notify us immediately by replying to the message and deleting it= from your computer. =0A=0A=0A=0A
=0A=
Good thing for= the PSN, the EQ woke my whole family and they asked me if it was an eart= hquake but I too was unable to get to any networks.  Hence right now= , with your response, is the only confirmation we have of it in the Midwe= st.  Earthquake watch.com doesn't even show it.
=0A=

=0A
=0A<= B>From: psn-l-request@.............. on behalf of Robert ThomassonSent: Fri 4/18/2008 5:00 AM
To: psn-l@..............Subject: Re: quake

=0A
It was a magnitude= 5.4 about 7 miles from West Salem, Illinois.  I picked it up very n= icely here in Reno.

=0A
On Fri, Apr 18, 20= 08 at 12:50 PM, Thomas Dick <dickthomas01@.............> wrote:
=0A
=0A
=0A
I don't know where but we just had a serious quake here in Evansvil= le In. Can't get out to some of the networks. It woke me. Lasted for almo= st a minute or more. Can anyone tell me where it was?
=0A 


NOTICE - This communi= cation may contain confidential and privileged information that is for th= e sole use of the intended recipient. Any viewing, copying or distributio= n of, or reliance on this message by unintended recipients is strictly pr= ohibited. If you have received this message in error, please notify us im= mediately by replying to the message and deleting it from your computer.<= /BODY>= Subject: RE: quake From: jonfr@......... Date: Fri, 18 Apr 2008 06:18:12 -0400 (EDT) Hi The earthquake is clearly visable on few plots that are in the U.S. I have a collection of them here, http://www.simnet.is/jonfr500/earthquake/othersten.htm Regards. Jón Frímann. > Good thing for the PSN, the EQ woke my whole family and they asked me if > it > was an earthquake but I too was unable to get to any networks. Hence > right > now, with your response, is the only confirmation we have of it in the > Midwest. Earthquake watch.com doesn't even show it. > > ________________________________ > > From: psn-l-request@.............. on behalf of Robert Thomasson > Sent: Fri 4/18/2008 5:00 AM > To: psn-l@.............. > Subject: Re: quake > > > It was a magnitude 5.4 about 7 miles from West Salem, Illinois. I picked > it > up very nicely here in Reno. > > > On Fri, Apr 18, 2008 at 12:50 PM, Thomas Dick > wrote: > > > I don't know where but we just had a serious quake here in Evansville > In. Can't get out to some of the networks. It woke me. Lasted for almost a > minute or more. Can anyone tell me where it was? > > > > > NOTICE - This communication may contain confidential and privileged > information that is for the sole use of the intended recipient. Any > viewing, copying or distribution of, or reliance on this message by > unintended recipients is strictly prohibited. If you have received this > message in error, please notify us immediately by replying to the message > and deleting it from your computer. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: "Thomas Dick" dickthomas01@............. Date: Fri, 18 Apr 2008 05:54:02 -0500 There are many aftershocks in the area. Quake about 60 (NW) miles away. I am very disappointed at my data -- can't see much. I am sure they will refine data soon. USGS preliminary data seems to be inaccurate. P arrival got here ..05 seconds later than USGS data would indicate. Maybe location (epicenter) is off. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: jonfr@......... Date: Fri, 18 Apr 2008 06:58:09 -0400 (EDT) Hi Low frequency sensors aren't good for local events. You would need something like an 4.5Hz sensor to see this event this close to your location properly. Regards. Jón Frímann. > There are many aftershocks in the area. Quake about 60 (NW) miles away. I > am > very disappointed at my data -- can't see much. I am sure they will refine > data soon. USGS preliminary data seems to be inaccurate. P arrival got > here > .05 seconds later than USGS data would indicate. Maybe location > (epicenter) > is off. > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: "Thomas Dick" dickthomas01@............. Date: Fri, 18 Apr 2008 06:16:43 -0500 You're right Jon, the geophone displays are better but still amplitudes make it almost impossible to see much -- distortion. .. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: jonfr@......... Date: Fri, 18 Apr 2008 07:31:57 -0400 (EDT) Hi I have my geophone on high amplitude. I haven't noticed any distortion. Noise I see, but no distortion. The biggest earthquake I have recored was a M4.3 at the distance of 85 km, no issues with that recording at all. Regards. Jón Frímann. > You're right Jon, the geophone displays are better but still amplitudes > make > it almost impossible to see much -- distortion. > . > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: "Thomas Dick" dickthomas01@............. Date: Fri, 18 Apr 2008 08:37:52 -0500 I see they downgraded the quake to 5.2. I describe it as a "serious" quake in my first posting. I suppose I based this on passed quakes in this locality which did not last as long. Certainly this lasted a lot longer. This one lasted at least 45 seconds e.g. felt for that long. We have lights on our desks that are suspended. The quake waves continued to vibrate for over two minutes. I used the word distortion of data. This quake was so strong and so close. If this were audio, I would describe the incoming data as being clipped. I saved six aftershocks out of maybe ten or more I considered significant. At least two were felt and reported by TV listeners as I watched my computer screen. Lehmans and AS-1 showed tendency toward peak in the .1 to .3 Hz range five minutes before quake on a relatively quiet display. And below .1 Hz just seconds before quake. Is that important? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: jonfr@......... Date: Fri, 18 Apr 2008 11:40:45 -0400 (EDT) Hi all There just was an aftershock now, emsc says it is M 4.5. See here, http://www.emsc-csem.org/index.php?page=current&sub=detail&id=84013 (might be outdated soon) By the looks of it, there is a slight chance of a swarm of mag 4.0 to 5.5 earthquakes, they might even go as high as mag 6.0. But that would be a rare event, but I am not expecting it. I however also don't rule it out. Regards. Jón Frímann. > I see they downgraded the quake to 5.2. I describe it as a "serious" quake > in my first posting. I suppose I based this on passed quakes in this > locality which did not last as long. Certainly this lasted a lot longer. > This one lasted at least 45 seconds e.g. felt for that long. We have > lights > on our desks that are suspended. The quake waves continued to vibrate for > over two minutes. I used the word distortion of data. This quake was so > strong and so close. If this were audio, I would describe the incoming > data > as being clipped. I saved six aftershocks out of maybe ten or more I > considered significant. At least two were felt and reported by TV > listeners > as I watched my computer screen. Lehmans and AS-1 showed tendency toward > peak in the .1 to .3 Hz range five minutes before quake on a relatively > quiet display. And below .1 Hz just seconds before quake. Is that > important? > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: "Thomas Dick" dickthomas01@............. Date: Fri, 18 Apr 2008 11:08:38 -0500 > There just was an aftershock now, emsc says it is M 4.5. See here, > http://www.emsc-csem.org/index.php?page=current&sub=detail&id=84013 (might > be outdated soon) > >Here in Indiana, before this last quake the FFT for 20 seconds just before >dropped to below one from over 10 before the first quake in the frequencies >of .06 to .3 Hz __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: Pete Rowe ptrowe@......... Date: Fri, 18 Apr 2008 10:21:08 -0700 (PDT) Loud and clear in San Jose, CA. It's on my website right now (www(dot)rowelabs(dot)com Enjoy Pete --- On Fri, 4/18/08, Thomas Dick wrote: > From: Thomas Dick > Subject: Re: quake > To: psn-l@.............. > Date: Friday, April 18, 2008, 9:08 AM > > There just was an aftershock now, emsc says it is M > 4.5. See here, > > > http://www.emsc-csem.org/index.php?page=current&sub=detail&id=84013 > (might > > be outdated soon) > > > >Here in Indiana, before this last quake the FFT for 20 > seconds just before > >dropped to below one from over 10 before the first > quake in the frequencies > >of .06 to .3 Hz > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more > information. ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: shammon1@............. Date: Fri, 18 Apr 2008 11:34:01 -0700 (GMT-07:00) Wow after looking at your site Pete I went and checked my long period AT1 in Aptos and can see I also recorded that event... (and I thought my system was not working that well.) I'm at Cabrillo College teaching a Social Justice Research class at the moment but when I get home I'll check and upload my data. I bet that Jan and Larry also recorded these events. Steve Hammond PSN San Jose, Aptos, CA http://pw2.netcom.com/~shammon1/recent.htm >Loud and clear in San Jose, CA. >It's on my website right now (www(dot)rowelabs(dot)com >Enjoy >Pete --- On Fri, 4/18/08, Thomas Dick wrote: > From: Thomas Dick > Subject: Re: quake > To: psn-l@.............. > Date: Friday, April 18, 2008, 9:08 AM > > There just was an aftershock now, emsc says it is M > 4.5. See here, > > > http://www.emsc-csem.org/index.php?page=current&sub=detail&id=84013 > (might > > be outdated soon) > > > >Here in Indiana, before this last quake the FFT for 20 > seconds just before > >dropped to below one from over 10 before the first > quake in the frequencies > >of .06 to .3 Hz > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more > information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Winquake From: "Thomas Dick" dickthomas01@............. Date: Sun, 20 Apr 2008 08:06:29 -0500 An unusual problem that I am sure those of you in California have = solved. These southern Illinois quakes that are over about a Magnitude = of 3 and less than fourty miles away appear to overloaded my system = causing clipping at peaks. Is there an adjustment within Windquake I = have missed?
An unusual problem that I am sure those = of you in=20 California have solved. These southern Illinois quakes that are over = about a=20 Magnitude of 3 and less than fourty miles away appear to overloaded my = system=20 causing clipping at peaks. Is there an adjustment within Windquake I = have=20 missed?
Subject: Re: Winquake From: "Geoff" gmvoeth@........... Date: Sun, 20 Apr 2008 07:48:46 -0700 I think you need what is called a log amplifier that had the gain characteristics of a PN junction knee ( from a curve tracer ) The gain decreases as the voltage increases. Then you can get both big and small without clipping but still that means you are seeing a distorted signal. Otherwise you need several channel in decades ( two or three ) then you can pick the largest signal that is not clipped. It is usually a hardware issue and not a software unless you are setting gain via shifting of A/D gain resolution(looking at top 8 bits instead of 12 ). ----- Original Message ----- From: "Thomas Dick" To: Sent: Sunday, April 20, 2008 6:06 AM Subject: Winquake An unusual problem that I am sure those of you in California have solved. These southern Illinois quakes that are over about a Magnitude of 3 and less than fourty miles away appear to overloaded my system causing clipping at peaks. Is there an adjustment within Windquake I have missed? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Winquake From: Pete Rowe ptrowe@......... Date: Sun, 20 Apr 2008 17:26:27 -0700 (PDT) Hi The problem with clipping is in the amplifiers ahead of the A/D. You can run the overall gain down a little and see if that helps. You would really like to know which stage is clipping and then adjust the gain until it doesn't. Ideally you would put a very small sine wave signal (1 Hz?) into the input of the amplifier chain in place of the coil. Then run the input level up until you get clipping at the A/D. Then, with an oscilloscope, trace through all of your stages to see where the clipping is occurring. You may want to re-distribute the gain or just reduce it to where you are happy with the way it performs on local quakes. I have many earthquakes in the less than magnitude 3 range (maybe 30 a month)and my A/D isn't anywhere near saturation. Yet, I can see a 7.0 anywhere on earth. Good luck and let us all know how you are progressing. Regards, Pete --- On Sun, 4/20/08, Thomas Dick wrote: > From: Thomas Dick > Subject: Winquake > To: psn-l@.............. > Date: Sunday, April 20, 2008, 6:06 AM > An unusual problem that I am sure those of you in California > have solved. These southern Illinois quakes that are over > about a Magnitude of 3 and less than fourty miles away > appear to overloaded my system causing clipping at peaks. > Is there an adjustment within Windquake I have missed? ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: Pete Rowe ptrowe@......... Date: Mon, 21 Apr 2008 12:40:38 -0700 (PDT) Hi Steve It's nice to know that you are still running your seismometer. The computer I'm using keeps crashing so I need a new XP machine. I just haven't gotten around to buying one. Regards, Pete --- On Fri, 4/18/08, shammon1@............. wrote: > From: shammon1@............. > Subject: Re: quake > To: psn-l@.............. > Date: Friday, April 18, 2008, 11:34 AM > Wow after looking at your site Pete I went and checked my > long period AT1 in Aptos and can see I also recorded that > event... (and I thought my system was not working that > well.) I'm at Cabrillo College teaching a Social > Justice Research class at the moment but when I get home > I'll check and upload my data. I bet that Jan and Larry > also recorded these events. > Steve Hammond PSN San Jose, Aptos, CA > > http://pw2.netcom.com/~shammon1/recent.htm > > > >Loud and clear in San Jose, CA. > >It's on my website right now > (www(dot)rowelabs(dot)com > >Enjoy > >Pete > > > --- On Fri, 4/18/08, Thomas Dick > wrote: > > > From: Thomas Dick > > Subject: Re: quake > > To: psn-l@.............. > > Date: Friday, April 18, 2008, 9:08 AM > > > There just was an aftershock now, emsc says it is > M > > 4.5. See here, > > > > > > http://www.emsc-csem.org/index.php?page=current&sub=detail&id=84013 > > (might > > > be outdated soon) > > > > > >Here in Indiana, before this last quake the FFT > for 20 > > seconds just before > > >dropped to below one from over 10 before the first > > quake in the frequencies > > >of .06 to .3 Hz > > > __________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email PSN-L-REQUEST@.............. > with > > the body of the message (first line only): unsubscribe > > See http://www.seismicnet.com/maillist.html for more > > information. > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more > information. ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: dueling earthquakes From: "Thomas Dick" dickthomas01@............. Date: Fri, 25 Apr 2008 12:54:29 -0500 Illinois and Nevada are in competitions -- I felt this one in southern = Indiana -- now its Nevada's turn
Illinois and Nevada are in competitions = -- I felt=20 this one in southern Indiana -- now its Nevada's = turn
Subject: Earthquake deteced near Greenland From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Fri, 25 Apr 2008 20:45:10 +0000 Hi all This morning my sensor did detect an earthquake near coast of Greenland. IMO says it is ML3.2, but given the distance from there sensors this is problay an underestimate of it's size. I would guess that it's size was around ML4.0 to ML4.4. It did appear nicely on my system, I will post it when I have final size and location on it. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: nevada earthqukaes From: jonfr@......... Date: Mon, 28 Apr 2008 16:43:41 -0400 (EDT) Hi all I've been looking at distribution of the Nevada earthquakes that have been happening over the past few weeks. Given the time space and the how dense the earthquake have been happening. I agree with the seismologist that have been saying the news that there is a good chance of big earthquake in that area. I would estimate that this big earthquake is 1 week to 5 weeks away from happening. If nothing special happens between now and then. The size estimate is from 6.5 to 7.5. For those of you that are close by this area. I would suggest that you keep a close on the micro earthquakes in the area. As the events now are pre-earthquakes before the big one hits. The intal earthquake before the big one might be a mag 5.5 earthquake, given it's current behavior. Regards. Jón Frímann. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: dueling earthquakes From: "Paul Cianciolo" Paulc@........ Date: Mon, 28 Apr 2008 17:16:43 -0400 Tom, Where to after Nevada? Paul -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of Thomas Dick Sent: Friday, April 25, 2008 1:54 PM To: psn-l@.............. Subject: dueling earthquakes Illinois and Nevada are in competitions -- I felt this one in southern Indiana -- now its Nevada's turn
Tom,
 
Where to after=20 Nevada?
 
Paul
-----Original Message-----
From: = psn-l-request@................. [mailto:psn-l-request@...............On Behalf Of Thomas=20 Dick
Sent: Friday, April 25, 2008 1:54 PM
To:=20 psn-l@..............
Subject: dueling=20 earthquakes

Illinois and Nevada are in = competitions -- I felt=20 this one in southern Indiana -- now its Nevada's=20 turn
Subject: RE: dueling earthquakes From: "Kareem, Heyjoojoo.Com" system98765@............. Date: Mon, 28 Apr 2008 17:50:18 -0700 I've been watching that area too (from California). It has been very interesting. To bring a "possible" California similarity into this, there have been similar patterns within the San Francisco Bay Area. Yes, we have had quake swarms all over the bay area, particularly in one area in what's known as the East Bay (Concord, Alamo area). The swarm lasted for a few weeks with the largest reaching 4.5 and then the activity abruptly stopped. But the swarms in Nevada do seem to reflect the dueling quake activity that occurred in our area during the 1800's (I wasn't here then) when there was a M6 quake in the east bay, followed years later by M7 quake in the Santa Cruz Mtns area (Loma Prieta area), only to be later followed by a M7 back in the east bay. It was sort of a battle of the bay - east bay vs. south bay. The area spans about 150 - 200 miles. I've been watching the depth of many of the quakes and most of them seem to be in the 0-7km range but there is the consistent number of events occurring deeper, in the 10-18km range too. Those deeper events might be more indicative of something maybe unusually large. Any comments? _____ From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Paul Cianciolo Sent: Monday, April 28, 2008 2:17 PM To: psn-l@.............. Subject: RE: dueling earthquakes Tom, Where to after Nevada? Paul -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of Thomas Dick Sent: Friday, April 25, 2008 1:54 PM To: psn-l@.............. Subject: dueling earthquakes Illinois and Nevada are in competitions -- I felt this one in southern Indiana -- now its Nevada's turn
I've been watching that area too (from = California). It has=20 been very interesting. To bring a "possible" California similarity into = this,=20 there have been similar patterns within the San Francisco Bay Area. Yes, = we have=20 had quake swarms all over the bay area, particularly in one area in = what's known=20 as the East Bay (Concord, Alamo area). The swarm lasted for a = few=20 weeks with the largest reaching 4.5 and then the activity abruptly = stopped.=20 But the swarms in Nevada do seem to reflect the dueling quake = activity that=20 occurred in our area during the 1800's (I wasn't here then) when there = was a M6=20 quake in the east bay, followed years later by M7 quake in the Santa = Cruz Mtns=20 area (Loma Prieta area), only to be later followed by a M7 back in the = east bay.=20 It was sort of a battle of the bay - east bay vs. south = bay. The area=20 spans about 150 - 200 miles.
 
I've been watching the depth of many of the = quakes and most=20 of them seem to be in the 0-7km range but there is the consistent number = of=20 events occurring deeper, in the 10-18km range too. Those deeper events = might be=20 more indicative of something maybe unusually large.
 
Any comments?
 

From: psn-l-request@................. [mailto:psn-l-request@............... On Behalf Of Paul=20 Cianciolo
Sent: Monday, April 28, 2008 2:17 PM
To:=20 psn-l@..............
Subject: RE: dueling=20 earthquakes

Tom,
 
Where to after=20 Nevada?
 
Paul
-----Original Message-----
From: = psn-l-request@................. [mailto:psn-l-request@...............On Behalf Of Thomas=20 Dick
Sent: Friday, April 25, 2008 1:54 PM
To:=20 psn-l@..............
Subject: dueling=20 earthquakes

Illinois and Nevada are in = competitions -- I felt=20 this one in southern Indiana -- now its Nevada's=20 turn
Subject: Meteoroid ? From: jonfr@......... Date: Tue, 29 Apr 2008 08:38:14 -0400 (EDT) Hi all I was speaking to an seismologist at IMO about the "earthquake" that happen the 25th April around 07:40. He did suggest that it was a Meteoroid rather then a earthquake, as the event was recored on most seismic stations in Iceland around the same time. He did suggests that this was an earthquake, but given the clues it seems unlikely. If this was a meteoroid, it is mostly likely that it did exploit high up in the atmosphere. But no explosion has been reported so far, but the area where this most likely did happen is unpopulated for most part. This was closer to Greenland then Iceland, it appears. I did also record this event and the trace can be seen here. http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0804/080425.073900.hvtz.psn http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0804/080425.073900.hvtn.psn http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0804/080425.073900.hvte.psn This is a filtered trace at 2Hz (I think, don't remember what I did filter it on). It would be nice to get a different opinion on this. Regards. Jón Frímann. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: dueling earthquakes From: "Thomas Dick" dickthomas01@............. Date: Tue, 29 Apr 2008 11:41:05 -0500 I don't think either Nevada or Southern Illinois is done yet. We are = still getting aftershocks and so is Nevada,
 
I don't think either Nevada or Southern Illinois = is done=20 yet. We are still getting aftershocks and so is=20 Nevada,
Subject: Re: dueling earthquakes From: "Thomas Dick" dickthomas01@............. Date: Tue, 29 Apr 2008 12:15:08 -0500 To bring a "possible" California similarity into this, there have been similar patterns within the San Francisco Bay Area. Yes, we have had quake swarms all over the bay area, particularly in one area in what's known as the East Bay (Concord, Alamo area). The swarm lasted for a few weeks with the largest reaching 4.5 and then the activity abruptly stopped. National TV News a few weeks ago suggested a major quake out there was to be expected. I think that thinking was stimulated by the recent quake activity in the Alaskan chain and down in South America.. But the swarms in Nevada do seem to reflect the dueling quake activity that occurred in our area during the 1800's (I wasn't here then) when there was a M6 quake in the east bay, followed years later by M7 quake in the Santa Cruz Mtns area (Loma Prieta area), only to be later followed by a M7 back in the east bay. It was sort of a battle of the bay - east bay vs. south bay. The area spans about 150 - 200 miles. The area out there is so complex. I've been watching the depth of many of the quakes and most of them seem to be in the 0-7km range but there is the consistent number of events occurring deeper, in the 10-18km range too. Those deeper events might be more indicative of something maybe unusually large. Any comments? Quakes in southern Illinois are deep because most of the faults are very old. One "felt" quake in 20 years is the norm. Most quakes the do not last long -- maybe less than 20 seconds --several of these recent quakes went on for over twice that time frame ....and usually are not centered in one area like this sequence. The sediments are also deep -- as much as 300 ft in many areas. This means they are felt! The shaking extends out. The news didn't really cover the aftereffects because there were no human injuries. I talked to an acquaintence living in the six mile diameter area of these quakes. He is a farmer. His home and outbuildings did just fine. But his mother's home was seriously damaged and he didn't know if it was worth fixing. And there are others in that area too. I expect things to quiet down here but Nevada and west coast may not be done. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Meteoroid ? From: "Geoff" gmvoeth@........... Date: Tue, 29 Apr 2008 10:56:03 -0700 I find it odd that an air explosion would cause a ground trace of that nature. Maybe someone can tell us what past air explosions have looked like. I would expect a meteor impact to look like a mine blast giving upward motion at first arrival all around the impact point. As for an air explosion would you see both P and s waves since air is a fluid and propagates no such S waves unless they form on contact with the Earth. Anyone have examples of air blast seismic signatures ? ----- Original Message ----- From: To: Sent: Tuesday, April 29, 2008 5:38 AM Subject: Meteoroid ? > Hi all > > I was speaking to an seismologist at IMO about the "earthquake" that > happen the 25th April around 07:40. He did suggest that it was a Meteoroid > rather then a earthquake, as the event was recored on most seismic > stations in Iceland around the same time. He did suggests that this was an > earthquake, but given the clues it seems unlikely. If this was a > meteoroid, it is mostly likely that it did exploit high up in the > atmosphere. But no explosion has been reported so far, but the area where > this most likely did happen is unpopulated for most part. This was closer > to Greenland then Iceland, it appears. > > I did also record this event and the trace can be seen here. > > http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0804/080425.073900.hvtz.psn > http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0804/080425.073900.hvtn.psn > http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0804/080425.073900.hvte.psn > > This is a filtered trace at 2Hz (I think, don't remember what I did filter > it on). > > It would be nice to get a different opinion on this. > > Regards. > Jón Frímann. > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: NZ tsunami warning network goes live From: Mark Robinson mark.robinson@............... Date: Wed, 30 Apr 2008 13:20:29 +1200 http://wildland.owdjim.gen.nz/?p=604 http://www.geonet.org.nz/tsunami/gauges/index.html http://www.geonet.org.nz/docs/tsunami/tsunami-brochure.pdf -- regards Mark Robinson ------------- 30 Apr 1991 A Cyclone hits Bangladesh killing over 125,000 people. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: A Historical magnet assembly for either eddy current dampening, or induction coil pickup From: "meredith lamb" paleoartifact@......... Date: Fri, 2 May 2008 13:29:36 -0600 Hi all, The below is a reference to a web page with pictures I put up, where; a older magnet and iron assembly does essentially the same tasks as earlier outlined in many past PSN emails by Chris Chapman. http://seismometer.googlepages.com/magnetpu%26d This old assembly could essentially be used obviously for either eddy current dampening and copper coil induction pickups in a seismometer. A main point with using such in a home brew seismometer, is that with the current availability of strong field neodymium magnets in a wide span of sizes; its relatively easy to fashion ones own unit; rather than use a simple two pole (usually) alnico magnet, with a far weaker magnetic field. Meredith Lamb Hi all,

The below is a reference to a web page with pictures I put up, where; a older magnet and iron assembly
does essentially the same tasks as earlier outlined in many past PSN emails by Chris Chapman. 

http://seismometer.googlepages.com/magnetpu%26d

This old assembly could essentially be used obviously for either eddy current dampening and copper
coil induction pickups in a seismometer. 

A main point with using such in a home brew seismometer, is that with the current availability of
strong field neodymium magnets in a wide span of sizes; its relatively easy to fashion ones own
unit; rather than use a simple two pole (usually) alnico magnet, with a far weaker magnetic field.

Meredith Lamb

 
Subject: Large eruption in Chile From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sat, 03 May 2008 19:30:59 +0000 Hi all There is a large eruption in Chile, the ash plume has reached 16 km yesterday when the eruption did start. The current information that I have is limited, but this is what I got on the volcano postlist yesterday. -------- Chait=E9n Southern Chile 42.833S, 72.646W; summit elev. 1,122 m All times are local (=3D UTC - 4 hours) Later updates from multiple sources have indicated that the 2 May 2008 eruption at Minchinm=E1vida (Vnum 1508-04) was incorrectly attributed. The volcano that erupted was an adjacent caldera, Chaiten (1508-041). A Volcanic Ash Advisory stated that ash rose to altitudes in the range of 45,000-55,000 feet [13.7-16.7 km]. Chaiten lies slightly to the W of Minchinmavida. Chaiten volcano lacks any known modern eruptions but a radiocarbon date on its tephra (CHA1) yields a date of 7,430 BC (plus or minus 75 years). Since my message this morning much news (in Spanish and English) has emerged about today's eruption at Chaiten, correcting the earlier confusion regarding the name and including numerous photos of impressive plumes. One report said 1,500 people were evacuated in Chile. What follows after the Geologic Summary are relevant portions of reports by others. My thanks to this listserve's Kimberly Genareau and these other contributors. Geologic Summary. Chait=E9n is a small, glacier-free late-Pleistocene caldera with a Holocene lava dome located 10 km NE of the town of Chait=E9n on the Gulf of Corcovado. The north side of the rhyolitic, 962-m-high obsidian lava dome occupying the 3.5-km-wide caldera is unvegetated. Obsidian cobbles from this dome found in the Blanco River are the source of prehistorical artifacts from archaeological sites along the Pacific coast as far as 400 km away from the volcano to the north and south. The caldera is breached on the SW side by a river that drains to the bay of Chait=E9n, and the high point on its southern rim reaches 1,122 m. Two small lakes occupy the caldera floor on the west and north sides of the lava dome. Moreno (1985 pers. comm.) noted that the nearby volcano of Yelcho listed by the International Association of Volcanology and Chemistry of the Earth's Interior (1973) does not exist. --------- Also, given the pictures that I have seen on the news. It can be save to assume that this eruption is not small. News here, http://afp.google.com/article/ALeqM5iTRpKWeEuLPkSc23OYxUGssHV3iA More news here, http://news.google.com/news?ned=3Dus&hl=3Den&ned=3Dus&q=3DChaiten&btnG=3DSe= arch +News This volcano last erupted in 7420 BC =B1 75 years. So it has lied dormant for a long time now. More information on the volcano here, http://www.volcano.si.edu/world/volcano.cfm?vnum=3D1508-041 If this is a really big eruption, it might create issues for the nearby countries. At least part of the south part of the planet. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Basic Programming Help desired? From: "Geoff" gmvoeth@........... Date: Sun, 4 May 2008 21:17:52 -0700 Hello PSN Peoples; I am trying to make a routine that will save an array of single bytes to a raw data file on the hard drive and do this as quickly as possible. Below you will see a routine that works very well for me but its too darn slow. When the program enters this routine it will linger for many seconds appearently converting the data array into the strings before eventually actually saving the data into the file. I do not understand the terrible long time this routine seems to take. Can someone with more experience please tell me what Im doing wrong that takes so long ( literally several seconds for only 32770 bytes total) to complete. I would like a speed that rivals a BSAVE command. This is how i save my seismic data to a raw 8 bit file after recording it to the array in RAM. Thanks for any help. feel free ro email me direct. Regards; geoff ********************************** POWERBASIC FOR DOS COMPILER SOURCE CODE $LIB COM ON $LIB FULLFLOAT ON $LIB VGA ON $ERROR BOUNDS ON $ERROR NUMERIC ON $ERROR OVERFLOW ON $ERROR STACK ON $CPU 80386 $COM 1024 $STRING 32 $STACK 2048 $SOUND 256 $DYNAMIC $COMPILE EXE "TEST.EXE" $FLOAT NPX $OPTIMIZE SPEED $EVENT $OPTION CNTLBREAK ON ' CREATE AN ARRAY FOR RAW DATA DIM VIRTUAL DATA_1?(0:32780) ' Fill the array with ascii text characters ' So resulting file can be easily examined ' with a hex editor normally this is the recording FOR a = 0 to 32780 : DATA_1?(a) = ( 65 + a MOD 58 ) : NEXT a ' Form a file path and name FILE1$ = "c:\data\test.dat" ' screen not necessary just habit SCREEN 11 ' below is the routine in question tmpz1$ = "" FOR ka = 0 to 32255 tmpz1$ = tmpz1$ + chr$(DATA_1?(ka)) NEXT ka tmpz2$ = "" FOR ka = 32256 to 32769 tmpz2$ = tmpz2$ + chr$(DATA_1?(ka)) NEXT ka OPEN FILE1$ FOR BINARY AS #1 SEEK #1,0 : PUT$ #1,tmpz1$ SEEK #1,32256 : PUT$ #1,tmpz2$ CLOSE #1 tmpz1$ = "" : tmpz2$ = "" ' task completed return to system SYSTEM ***************************** __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: Mark Robinson mark.robinson@............... Date: Mon, 05 May 2008 17:21:45 +1200 Geoff wrote: > Hello PSN Peoples; > > I am trying to make a routine > that will save an array of single > bytes to a raw data file on the hard > drive and do this as quickly as possible. > Below you will see a routine that works > very well for me but its too darn slow. > When the program enters this routine > it will linger for many seconds > appearently converting the data array > into the strings before eventually > actually saving the data into the file. > I do not understand the terrible long > time this routine seems to take. > > Can someone with more experience > please tell me what Im doing wrong > that takes so long ( literally several > seconds for only 32770 bytes total) to complete. > I would like a speed that rivals a BSAVE command. Your first mistake is using Basic. This will be between 10 and 1000 times slower than a compiled language. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: "Geoff" gmvoeth@........... Date: Sun, 4 May 2008 23:09:26 -0700 You are speaking from an ignorant view point. Just Like Me :-) If you study programming languages you will find Power Basic one of the best BASIC Compilers out there for MSDOS machines. I hate C++ and really like BASIC and FORTRAN and ASSEMBLY if the computer world had concentrated on developing BASIC there would be nothing today that would compare since BASIC was the laymans Tool. We need standards so that everyone can do whatever without the Tower of Babel messing things up. Assembly is by far the best for speed but try getting your hands on register maps for all the hardwares out there. I hope Im Wrong The Flavor of Your response here is just like those Counter Intelligent News peoples that are ubiquitous on the news servers. Im hoping you are a kid and not an adult. Like I said you are somewhat ignorant like me :-) Best Regards; geoff ----- Original Message ----- From: "Mark Robinson" To: Sent: Sunday, May 04, 2008 10:21 PM Subject: Re: Basic Programming Help desired? > Geoff wrote: >> Hello PSN Peoples; >> >> I am trying to make a routine >> that will save an array of single >> bytes to a raw data file on the hard >> drive and do this as quickly as possible. >> Below you will see a routine that works >> very well for me but its too darn slow. >> When the program enters this routine >> it will linger for many seconds >> appearently converting the data array >> into the strings before eventually >> actually saving the data into the file. >> I do not understand the terrible long >> time this routine seems to take. >> >> Can someone with more experience >> please tell me what Im doing wrong >> that takes so long ( literally several >> seconds for only 32770 bytes total) to complete. >> I would like a speed that rivals a BSAVE command. > > Your first mistake is using Basic. > > This will be between 10 and 1000 times slower than a compiled language. > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Basic Programming Help desired? From: "Timothy Carpenter" geodynamics@....... Date: Mon, 5 May 2008 10:40:15 -0400 Geoff, My experience is with the various versions of MS Basic, not Powerbasic. However, the following comments may help. Check the effects of the various compiler directives on the speed of the routine. In particular, check the effects of the various error handlers. Turning them off may increase the speed. I think your biggest hangup is creating a long string from your raw data -- that's a huge amount of unnecessary conversions. Instead, you should consider creating a binary file () and then writing (stream) the individual bytes to the file as soon as you receive them from the AD card. Here's a link to a routine that may give you some guidance: http://www.vb-helper.com/howto_read_write_binary_file.html Also, check the utilities and tools that may have accompanied your AD card. Often the manufacturer will supply tools and/or examples that allow you to stream data directly from the card to disk. Check their website too. Some (most?) versions of Basic are intrinsically slow because they are not truly compiled in the way FORTRAN would be. In your case it probably isn't necessary, but if you really need the speed, then you should consider some other language besides Basic -- e.g., C (C++), Fortran and ultimately, Assembly. Regards, -Tim- -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Geoff Sent: Monday, May 05, 2008 12:18 AM To: PSN Subject: Basic Programming Help desired? Hello PSN Peoples; I am trying to make a routine that will save an array of single bytes to a raw data file on the hard drive and do this as quickly as possible. Below you will see a routine that works very well for me but its too darn slow. When the program enters this routine it will linger for many seconds appearently converting the data array into the strings before eventually actually saving the data into the file. I do not understand the terrible long time this routine seems to take. Can someone with more experience please tell me what Im doing wrong that takes so long ( literally several seconds for only 32770 bytes total) to complete. I would like a speed that rivals a BSAVE command. This is how i save my seismic data to a raw 8 bit file after recording it to the array in RAM. Thanks for any help. feel free ro email me direct. Regards; geoff ********************************** POWERBASIC FOR DOS COMPILER SOURCE CODE $LIB COM ON $LIB FULLFLOAT ON $LIB VGA ON $ERROR BOUNDS ON $ERROR NUMERIC ON $ERROR OVERFLOW ON $ERROR STACK ON $CPU 80386 $COM 1024 $STRING 32 $STACK 2048 $SOUND 256 $DYNAMIC $COMPILE EXE "TEST.EXE" $FLOAT NPX $OPTIMIZE SPEED $EVENT $OPTION CNTLBREAK ON ' CREATE AN ARRAY FOR RAW DATA DIM VIRTUAL DATA_1?(0:32780) ' Fill the array with ascii text characters ' So resulting file can be easily examined ' with a hex editor normally this is the recording FOR a = 0 to 32780 : DATA_1?(a) = ( 65 + a MOD 58 ) : NEXT a ' Form a file path and name FILE1$ = "c:\data\test.dat" ' screen not necessary just habit SCREEN 11 ' below is the routine in question tmpz1$ = "" FOR ka = 0 to 32255 tmpz1$ = tmpz1$ + chr$(DATA_1?(ka)) NEXT ka tmpz2$ = "" FOR ka = 32256 to 32769 tmpz2$ = tmpz2$ + chr$(DATA_1?(ka)) NEXT ka OPEN FILE1$ FOR BINARY AS #1 SEEK #1,0 : PUT$ #1,tmpz1$ SEEK #1,32256 : PUT$ #1,tmpz2$ CLOSE #1 tmpz1$ = "" : tmpz2$ = "" ' task completed return to system SYSTEM ***************************** __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: "Geoff" gmvoeth@........... Date: Mon, 5 May 2008 09:15:29 -0700 THANK you but this is not the problem I am addressing. A/D is not the concern at this time. ALL data is saved to an array that resides somewhere in MSDOS EMS RAM. What I am trying to do is save that array as fast as possible FROM RAM to a file residing on hard disk. This lets me turn off the disk while the recorder is running and turn on the drive only for file operations ( permanent storage ). I have always had troubles quickly dealing with file formation and lots of bytes. If you play with BSAVE command you will find it is almost instant unlike my own programs. If only I could make a program as fast as BSAVE BASIC command then I could do anything I need to in this regard very quickly and miss few samples inbetween recordings. Immediately below is the routine which does this operation as fast as I have ever done it. Comments are welcome. Regards; geoff ************************* $LIB COM ON $LIB FULLFLOAT ON $LIB VGA ON $ERROR BOUNDS ON $ERROR NUMERIC ON $ERROR OVERFLOW ON $ERROR STACK ON $CPU 80386 $COM 1024 $STRING 32 $STACK 2048 $SOUND 256 $DYNAMIC $COMPILE EXE "TEST.EXE" $FLOAT NPX $OPTIMIZE SPEED $EVENT $OPTION CNTLBREAK ON DIM VIRTUAL DATA_1?(0:32780) ' Create a test set of data FOR a = 0 to 32780 : DATA_1?(a) = ( 65 + a MOD 58 ) : NEXT a ' Create the path and filename FILE1$ = "c:\data\test.dat" ' Write The Array in EMS RAM To The File on HARD Drive CLS PRINT "NOW SAVING DATA TO FILE c:\data\test.dat " OPEN FILE1$ FOR BINARY AS #1 FOR ka = 0 to 7 tmpz1$ = "" For kb = 0 to 4095 kc = (( ka * 4096 ) + kb ) tmpz1$ = tmpz1$ + chr$(DATA_1?(kc)) NEXT kb kd = ( ka * 4096 ) SEEK #1,kd : PUT$ #1,tmpz1$ NEXT ka tmpz1$ = "" FOR ka = 32256 to 32769 tmpz1$ = tmpz1$ + chr$(DATA_1?(ka)) NEXT ka SEEK #1,32256 : PUT$ #1,tmpz1$ CLOSE #1 tmpz1$ = "" END ********* ----- Original Message ----- From: "Timothy Carpenter" To: Sent: Monday, May 05, 2008 7:40 AM Subject: RE: Basic Programming Help desired? > Geoff, > > My experience is with the various versions of MS Basic, not Powerbasic. > However, the following comments may help. > > Check the effects of the various compiler directives on the speed of the > routine. In particular, check the effects of the various error handlers. > Turning them off may increase the speed. > > I think your biggest hangup is creating a long string from your raw data -- > that's a huge amount of unnecessary conversions. Instead, you should > consider creating a binary file () and then writing > (stream) the individual bytes to the file as soon as you receive them from > the AD card. > > Here's a link to a routine that may give you some guidance: > http://www.vb-helper.com/howto_read_write_binary_file.html > > Also, check the utilities and tools that may have accompanied your AD card. > Often the manufacturer will supply tools and/or examples that allow you to > stream data directly from the card to disk. Check their website too. > > Some (most?) versions of Basic are intrinsically slow because they are not > truly compiled in the way FORTRAN would be. In your case it probably isn't > necessary, but if you really need the speed, then you should consider some > other language besides Basic -- e.g., C (C++), Fortran and ultimately, > Assembly. > > Regards, > -Tim- > > > -----Original Message----- > From: psn-l-request@.............. [mailto:psn-l-request@............... On > Behalf Of Geoff > Sent: Monday, May 05, 2008 12:18 AM > To: PSN > Subject: Basic Programming Help desired? > > Hello PSN Peoples; > > I am trying to make a routine > that will save an array of single > bytes to a raw data file on the hard > drive and do this as quickly as possible. > Below you will see a routine that works > very well for me but its too darn slow. > When the program enters this routine > it will linger for many seconds > appearently converting the data array > into the strings before eventually > actually saving the data into the file. > I do not understand the terrible long > time this routine seems to take. > > Can someone with more experience > please tell me what Im doing wrong > that takes so long ( literally several > seconds for only 32770 bytes total) to complete. > I would like a speed that rivals a BSAVE command. > > This is how i save my seismic data > to a raw 8 bit file > after recording it to the array > in RAM. > > Thanks for any help. > feel free ro email me direct. > > Regards; > geoff > > ********************************** > POWERBASIC FOR DOS COMPILER SOURCE CODE > > $LIB COM ON > $LIB FULLFLOAT ON > $LIB VGA ON > $ERROR BOUNDS ON > $ERROR NUMERIC ON > $ERROR OVERFLOW ON > $ERROR STACK ON > $CPU 80386 > $COM 1024 > $STRING 32 > $STACK 2048 > $SOUND 256 > $DYNAMIC > $COMPILE EXE "TEST.EXE" > $FLOAT NPX > $OPTIMIZE SPEED > $EVENT > $OPTION CNTLBREAK ON > > ' CREATE AN ARRAY FOR RAW DATA > DIM VIRTUAL DATA_1?(0:32780) > ' Fill the array with ascii text characters > ' So resulting file can be easily examined > ' with a hex editor normally this is the recording > FOR a = 0 to 32780 : DATA_1?(a) = ( 65 + a MOD 58 ) : NEXT a > ' Form a file path and name > FILE1$ = "c:\data\test.dat" > ' screen not necessary just habit > SCREEN 11 > ' below is the routine in question > tmpz1$ = "" > FOR ka = 0 to 32255 > tmpz1$ = tmpz1$ + chr$(DATA_1?(ka)) > NEXT ka > tmpz2$ = "" > FOR ka = 32256 to 32769 > tmpz2$ = tmpz2$ + chr$(DATA_1?(ka)) > NEXT ka > OPEN FILE1$ FOR BINARY AS #1 > SEEK #1,0 : PUT$ #1,tmpz1$ > SEEK #1,32256 : PUT$ #1,tmpz2$ > CLOSE #1 > tmpz1$ = "" : tmpz2$ = "" > ' task completed return to system > SYSTEM > > > ***************************** > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: Canie canie@........... Date: Mon, 05 May 2008 09:52:41 -0700 I've worked with basic programming for about 30 years.. no ms basic, but a flavor of basic.. and whenever we were trying to speed such things up, it was known that for-next loops were rather slow... You might play around with a while-wend statements to see if that executes and faster, or just use a counter and gotos... interesting test for timing of things.. Canie At 09:15 AM 5/5/2008, you wrote: >THANK you but this is not the problem I am addressing. >A/D is not the concern at this time. >ALL data is saved to an array that resides somewhere >in MSDOS EMS RAM. What I am trying to do is >save that array as fast as possible FROM RAM to a file >residing on hard disk. This lets me turn off the >disk while the recorder is running and turn on the drive >only for file operations ( permanent storage ). >I have always had troubles quickly dealing with >file formation and lots of bytes. >If you play with BSAVE command you will >find it is almost instant unlike my own programs. >If only I could make a program as fast as BSAVE >BASIC command then I could do anything I need to >in this regard very quickly and miss few samples >inbetween recordings. > >Immediately below is the routine which does this >operation as fast as I have ever done it. >Comments are welcome. > >Regards; >geoff > >************************* >$LIB COM ON >$LIB FULLFLOAT ON >$LIB VGA ON >$ERROR BOUNDS ON >$ERROR NUMERIC ON >$ERROR OVERFLOW ON >$ERROR STACK ON >$CPU 80386 >$COM 1024 >$STRING 32 >$STACK 2048 >$SOUND 256 >$DYNAMIC >$COMPILE EXE "TEST.EXE" >$FLOAT NPX >$OPTIMIZE SPEED >$EVENT >$OPTION CNTLBREAK ON > >DIM VIRTUAL DATA_1?(0:32780) > >' Create a test set of data >FOR a = 0 to 32780 : DATA_1?(a) = ( 65 + a MOD 58 ) : NEXT a >' Create the path and filename >FILE1$ = "c:\data\test.dat" >' Write The Array in EMS RAM To The File on HARD Drive >CLS >PRINT "NOW SAVING DATA TO FILE c:\data\test.dat " >OPEN FILE1$ FOR BINARY AS #1 >FOR ka = 0 to 7 > tmpz1$ = "" > For kb = 0 to 4095 > kc = (( ka * 4096 ) + kb ) > tmpz1$ = tmpz1$ + chr$(DATA_1?(kc)) > NEXT kb > kd = ( ka * 4096 ) > SEEK #1,kd : PUT$ #1,tmpz1$ >NEXT ka >tmpz1$ = "" >FOR ka = 32256 to 32769 > tmpz1$ = tmpz1$ + chr$(DATA_1?(ka)) >NEXT ka >SEEK #1,32256 : PUT$ #1,tmpz1$ >CLOSE #1 >tmpz1$ = "" >END >********* __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: "Geoff" gmvoeth@........... Date: Mon, 5 May 2008 12:09:30 -0700 Roger Wilco Canie; I have found when dealing with the disk it matters how many bytes you can deal with in a single instruction/operation and that those bytes match the sector sizes on the disk itself. I think that one sector can be entirely written in a single write operation but if you use odd sizes it slows things down. Possibly the way the compiler does things is also important like DMA or Interrupt type programming. DMA between ram and disk is most probably the best way to go for a stable machine. But this would require assembly programming of a custom nature and Id have to go back to school to be able to do this. The sector sizes vary according to where you are on the disk and what the format type happens to be. It seems to me that powers of two relating to 512 bytes is possible the right thing to do. Someone has all the answers but finding a willing person to share such knowledge is very difficult for myself. Such expert people are typically too sensitive about sharing knowledge. They are capitalists with eyes that see only money and not true amateurs seeking and sharing knowledge. Thanks for your input. DMA = Direct memory access where you wind up the hard drive ( or whatever ) and it goes and gets its own data from ram by itself using the transfer times between machine (CPU) cycles. regards; geoff ----- Original Message ----- From: "Canie" To: Sent: Monday, May 05, 2008 9:52 AM Subject: Re: Basic Programming Help desired? > I've worked with basic programming for about 30 years.. no ms basic, > but a flavor of basic.. and whenever we were trying to speed such > things up, it was known that for-next loops were rather slow... > > You might play around with a while-wend statements to see if that > executes and faster, or just use a counter and gotos... interesting > test for timing of things.. > > Canie > > At 09:15 AM 5/5/2008, you wrote: >>THANK you but this is not the problem I am addressing. >>A/D is not the concern at this time. >>ALL data is saved to an array that resides somewhere >>in MSDOS EMS RAM. What I am trying to do is >>save that array as fast as possible FROM RAM to a file >>residing on hard disk. This lets me turn off the >>disk while the recorder is running and turn on the drive >>only for file operations ( permanent storage ). >>I have always had troubles quickly dealing with >>file formation and lots of bytes. >>If you play with BSAVE command you will >>find it is almost instant unlike my own programs. >>If only I could make a program as fast as BSAVE >>BASIC command then I could do anything I need to >>in this regard very quickly and miss few samples >>inbetween recordings. >> >>Immediately below is the routine which does this >>operation as fast as I have ever done it. >>Comments are welcome. >> >>Regards; >>geoff >> >>************************* >>$LIB COM ON >>$LIB FULLFLOAT ON >>$LIB VGA ON >>$ERROR BOUNDS ON >>$ERROR NUMERIC ON >>$ERROR OVERFLOW ON >>$ERROR STACK ON >>$CPU 80386 >>$COM 1024 >>$STRING 32 >>$STACK 2048 >>$SOUND 256 >>$DYNAMIC >>$COMPILE EXE "TEST.EXE" >>$FLOAT NPX >>$OPTIMIZE SPEED >>$EVENT >>$OPTION CNTLBREAK ON >> >>DIM VIRTUAL DATA_1?(0:32780) >> >>' Create a test set of data >>FOR a = 0 to 32780 : DATA_1?(a) = ( 65 + a MOD 58 ) : NEXT a >>' Create the path and filename >>FILE1$ = "c:\data\test.dat" >>' Write The Array in EMS RAM To The File on HARD Drive >>CLS >>PRINT "NOW SAVING DATA TO FILE c:\data\test.dat " >>OPEN FILE1$ FOR BINARY AS #1 >>FOR ka = 0 to 7 >> tmpz1$ = "" >> For kb = 0 to 4095 >> kc = (( ka * 4096 ) + kb ) >> tmpz1$ = tmpz1$ + chr$(DATA_1?(kc)) >> NEXT kb >> kd = ( ka * 4096 ) >> SEEK #1,kd : PUT$ #1,tmpz1$ >>NEXT ka >>tmpz1$ = "" >>FOR ka = 32256 to 32769 >> tmpz1$ = tmpz1$ + chr$(DATA_1?(ka)) >>NEXT ka >>SEEK #1,32256 : PUT$ #1,tmpz1$ >>CLOSE #1 >>tmpz1$ = "" >>END >>********* > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: Canie canie@........... Date: Mon, 05 May 2008 15:12:38 -0700 Yes - size of the data record can have such an effect.. all these little things that you'de wish the Microsoft engineers would know.. We always tried to do record sizes (of file definition sizes) of 64, 256, 512, 1024 bytes..for that reason - the disk writes would be faster.. And for some reason division is slower that multiplication.. so for certain things, rather than divide, we'de figure out how to multiply.. also these things can be compiler dependant I assume.. Canie At 12:09 PM 5/5/2008, you wrote: >Roger Wilco Canie; > >I have found when dealing with the disk >it matters how many bytes you can deal with >in a single instruction/operation and that those bytes >match the sector sizes on the disk itself. >I think that one sector can be entirely >written in a single write operation >but if you use odd sizes it slows things down. >Possibly the way the compiler does things >is also important like DMA or Interrupt >type programming. DMA between ram and disk >is most probably the best way to go for a >stable machine. But this would require >assembly programming of a custom nature >and Id have to go back to school to >be able to do this. >The sector sizes vary according to >where you are on the disk and what the >format type happens to be. >It seems to me that powers of two relating to >512 bytes is possible the right thing to do. >Someone has all the answers but finding >a willing person to share such knowledge >is very difficult for myself. Such expert people are >typically too sensitive about sharing knowledge. >They are capitalists with eyes that see only money >and not true amateurs seeking and sharing knowledge. >Thanks for your input. >DMA = Direct memory access where you wind up the hard >drive ( or whatever ) and it goes and gets its own data from ram >by itself using the transfer times between machine (CPU) cycles. >regards; >geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: "Geoff" gmvoeth@........... Date: Mon, 5 May 2008 17:44:00 -0700 Canie, And Others of PSN Many thanks for your input; Here is what I have found and will use this routine within my main recording program. If I run this on my desktop which is a pc3200 ram and 3GHz pentium4 Prescott device CPU and ATA100 Hard drives I get a time of 0.164 seconds a wonderful time. But if i run this on the laptop I use to record seismic events I get a time 17 times slower or 2.856 seconds ( Toshiba Satellite 205CDS Laptop ) It appears I shall loose about 4 to 5 seconds or record time between file saves with all the delays. The drive on the laptop is normally off and must rev up prior to saving the file but thats only a second or so of time. Below is the Routine I will install at the end of my program you all are free to have and to hold it until death you part. It will love honor and obey you, I hope. ******************************************* ' FILENAME TEST.BAS ' POWERBASIC For DOS 3.5 SOURCE CODE $LIB COM ON $LIB FULLFLOAT ON $LIB VGA ON $ERROR BOUNDS ON $ERROR NUMERIC ON $ERROR OVERFLOW ON $ERROR STACK ON $CPU 80386 $COM 1024 $STRING 32 $STACK 2048 $SOUND 256 $DYNAMIC $COMPILE EXE "TEST.EXE" $FLOAT NPX $OPTIMIZE SPEED $EVENT $OPTION CNTLBREAK ON DIM VIRTUAL DATA_1?(0:32780) FOR a = 0 to 32780 : DATA_1?(a) = ( 65 + a MOD 58 ) : NEXT a FILE1$ = "c:\data\test.dat" START1 = TIMER OPEN FILE1$ FOR BINARY AS #1 FOR ka = 0 to 7 tmpz1$ = "" kc = ( ka * 4096 ) SEEK #1,kc FOR kb = 0 to 4095 kd = ( kc + kb ) tmpz1$ = tmpz1$ + chr$(DATA_1?(kd)) NEXT kb PUT$ #1,tmpz1$ NEXT ka tmpz1$ = "" SEEK #1,32768 FOR ka = 32768 to 32769 tmpz1$ = tmpz1$ + chr$(DATA_1?(ka)) NEXT ka PUT$ #1,tmpz1$ CLOSE #1 tmpz1$ = "" STOP1 = TIMER IF START1 > STOP1 THEN START1 = START1 + 86400 PRINT "FILE CREATION RUNTIME :"; ROUND(( STOP1 - START1 ) , 3 ) SLEEP 10 END ****************************************************8 I will bother you no more with this unless someone has more to say. Best regards; geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: "Geoff" gmvoeth@........... Date: Tue, 6 May 2008 06:32:48 -0700 Many thanks Canie, I do not know if I have answered this yet but me thinks not. I will have to experiment myself from this point on to learn more since no one has exact answers I was looking for. There should be one fastest way of all to transfer data from an array to a hard disk file and no one seems to know what it is. If I could see how BASIC BSAVE command is working I may have my answer because it by far is the lightning fast quickness I wish to have. But when I tried the BSAVE command none of the data was in the correct order and saved were more bytes then I wanted to save. For me to unassemble the BSAVE routine would be a violation of the reverse engineering agreement in any licenses so that is out of the question for myself. I am using a Virtual Array ( Located In EMS Memory ) and not REAL MODE memory ( First 1MB ) and there is a possibility BSAVE may only function well in the REAL MODE instead of PROTECTED MODE ( EVERYTHING ABOVE 1MB ) . If I try to limit my entire program to REAL MODE then things may be faster too. The Originators of the IBM PC were more oriented to Business Administration then to science so security of design was way overboard and terribly subtracts from IBM PC performance. What is needed is the entire machine be REAL MODE without the stupid form of Paginated RAM and Interrupt ( TIME Sharing ) based design. They have tried to do too much with a serial CPU device which for best speed should only run one program at a time. Best Regards; geoff ----- Original Message ----- From: "Canie" To: Sent: Monday, May 05, 2008 3:12 PM Subject: Re: Basic Programming Help desired? > Yes - size of the data record can have such an effect.. all these > little things that you'de wish the Microsoft engineers would know.. > > We always tried to do record sizes (of file definition sizes) of 64, > 256, 512, 1024 bytes..for that reason - the disk writes would be faster.. > > And for some reason division is slower that multiplication.. so for > certain things, rather than divide, we'de figure out how to > multiply.. also these things can be compiler dependant I assume.. > > Canie > > At 12:09 PM 5/5/2008, you wrote: >>Roger Wilco Canie; >> >>I have found when dealing with the disk >>it matters how many bytes you can deal with >>in a single instruction/operation and that those bytes >>match the sector sizes on the disk itself. >>I think that one sector can be entirely >>written in a single write operation >>but if you use odd sizes it slows things down. >>Possibly the way the compiler does things >>is also important like DMA or Interrupt >>type programming. DMA between ram and disk >>is most probably the best way to go for a >>stable machine. But this would require >>assembly programming of a custom nature >>and Id have to go back to school to >>be able to do this. >>The sector sizes vary according to >>where you are on the disk and what the >>format type happens to be. >>It seems to me that powers of two relating to >>512 bytes is possible the right thing to do. >>Someone has all the answers but finding >>a willing person to share such knowledge >>is very difficult for myself. Such expert people are >>typically too sensitive about sharing knowledge. >>They are capitalists with eyes that see only money >>and not true amateurs seeking and sharing knowledge. >>Thanks for your input. >>DMA = Direct memory access where you wind up the hard >>drive ( or whatever ) and it goes and gets its own data from ram >>by itself using the transfer times between machine (CPU) cycles. >>regards; >>geoff > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: "Geoff" gmvoeth@........... Date: Tue, 6 May 2008 10:05:10 -0700 The Following Results Found; I changed VIRTUAL Array to HUGE which I belive keeps everything below the DOS 1MB RAM boundary and then used a RANDOM instead of a BINARY OPEN command. It seems RANDOM is best for numbers and BINARY is best for Strings if you want to do things byte by byte in PowerBasic For DOS. EVERYTHING now becomes; $LIB COM ON $LIB FULLFLOAT ON $LIB VGA ON $ERROR BOUNDS ON $ERROR NUMERIC ON $ERROR OVERFLOW ON $ERROR STACK ON $CPU 80386 $COM 1024 $STRING 32 $STACK 2048 $SOUND 256 $DYNAMIC $COMPILE EXE "TEST.EXE" $FLOAT NPX $OPTIMIZE SPEED $EVENT $OPTION CNTLBREAK ON DIM HUGE DATA_1?(0:32769) FOR A = 0 to 32769 : DATA_1?(A) = ( 65 + A MOD 58 ) : NEXT A FILE1$ = "c:\data\test.dat" START1 = TIMER OPEN FILE1$ FOR RANDOM AS #1 LEN = 1 FOR A?? = 0 to 32769 PUT #1,A?? + 1,DATA_1?(A??) NEXT A?? CLOSE STOP1 = TIMER IF START1 > STOP1 THEN START1 = START1 + 86400 PRINT "FILE CREATION RUNTIME :"; ROUND(( STOP1 - START1 ) , 3 ) ' KILL FILE1$ SLEEP 3 END Best regards geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: ian ian@........... Date: Tue, 06 May 2008 18:32:33 +0100 Hi, I'm not familiar with this flavour of basic but 2 comments: Is the for loop meant to be 0 to 32769? Normally it would be 32767 for 15 bits - I don't know the application for this code. When coding loops, I found it better (runs faster) to repeat the code in the loop and reduce the number of times around the loop, 16 being optimum. For example: FOR A = 0 to 2047 DATA_1?(A*16 + 0) = ( 65 + (A*16 + 0) MOD 58 ) DATA_1?(A*16 + 1) = ( 65 + (A*16 + 1) MOD 58 ) DATA_1?(A*16 + 2) = ( 65 + (A*16 + 2) MOD 58 ) DATA_1?(A*16 + 3) = ( 65 + (A*16 + 3) MOD 58 ) DATA_1?(A*16 + 4) = ( 65 + (A*16 + 4) MOD 58 ) DATA_1?(A*16 + 5) = ( 65 + (A*16 + 5) MOD 58 ) DATA_1?(A*16 + 6) = ( 65 + (A*16 + 6) MOD 58 ) DATA_1?(A*16 + 7) = ( 65 + (A*16 + 7) MOD 58 ) DATA_1?(A*16 + 8) = ( 65 + (A*16 + 8) MOD 58 ) DATA_1?(A*16 + 9) = ( 65 + (A*16 + 9) MOD 58 ) DATA_1?(A*16 + 10) = ( 65 + (A*16 + 10) MOD 58 ) DATA_1?(A*16 + 11) = ( 65 + (A*16 + 11) MOD 58 ) DATA_1?(A*16 + 12) = ( 65 + (A*16 + 12) MOD 58 ) DATA_1?(A*16 + 13) = ( 65 + (A*16 + 13) MOD 58 ) DATA_1?(A*16 + 14) = ( 65 + (A*16 + 14) MOD 58 ) DATA_1?(A*16 + 15) = ( 65 + (A*16 + 15) MOD 58 ) NEXT A DATA_1?(32768) = ( 65 + 32768 MOD 58 ) DATA_1?(32769) = ( 65 + 32769 MOD 58 ) This isn't debugged or known to be syntactically correct. Might be worth trying though... Ian Geoff wrote: > The Following Results Found; > > I changed VIRTUAL Array to HUGE > which I belive keeps everything > below the DOS 1MB RAM boundary > and then used a RANDOM instead of a > BINARY OPEN command. It seems RANDOM > is best for numbers and BINARY > is best for Strings if you want to > do things byte by byte in PowerBasic For DOS. > EVERYTHING now becomes; > > $LIB COM ON > $LIB FULLFLOAT ON > $LIB VGA ON > $ERROR BOUNDS ON > $ERROR NUMERIC ON > $ERROR OVERFLOW ON > $ERROR STACK ON > $CPU 80386 > $COM 1024 > $STRING 32 > $STACK 2048 > $SOUND 256 > $DYNAMIC > $COMPILE EXE "TEST.EXE" > $FLOAT NPX > $OPTIMIZE SPEED > $EVENT > $OPTION CNTLBREAK ON > > DIM HUGE DATA_1?(0:32769) > FOR A = 0 to 32769 : DATA_1?(A) = ( 65 + A MOD 58 ) : NEXT A > FILE1$ = "c:\data\test.dat" > START1 = TIMER > OPEN FILE1$ FOR RANDOM AS #1 LEN = 1 > FOR A?? = 0 to 32769 > PUT #1,A?? + 1,DATA_1?(A??) > NEXT A?? > CLOSE > STOP1 = TIMER > IF START1 > STOP1 THEN START1 = START1 + 86400 > PRINT "FILE CREATION RUNTIME :"; ROUND(( STOP1 - START1 ) , 3 ) > ' KILL FILE1$ > SLEEP 3 > END > > Best regards > geoff > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of > the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: "Dale Hardy" photon1@........... Date: Wed, 7 May 2008 08:42:36 +1000 Geoff, I have been using RapidQ basic. Very ACTIVE user group with strong support and very helpful not too far removed from your basic regards Dale http://rapidq.phatcode.net/ ----- Original Message ----- From: "Geoff" To: Sent: Tuesday, May 06, 2008 2:15 AM Subject: Re: Basic Programming Help desired? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: My lehman type sensor is ready From: jonfr@......... Date: Thu, 8 May 2008 09:28:40 -0400 (EDT) Hi all My lehman type sensor is ready. I hope that it gives me up to 30 seconds peroid. But I won't know if that is the case of not until tomorrow when I put it online at home. Here are two pictures of it. http://www.jonfr.com/myndir/v/geology/seismometer/DSC00432.JPG.html http://www.jonfr.com/myndir/v/geology/seismometer/DSC00433.JPG.html If hit by a blank page, just press enter and it should load properly. The mass is about ~1.5kg. The arm is ~70 cm and the mass is located at the ~65 cm limit of it. I used to speaker magnets as damping magnest. The coil and the maget are from Larry. At current setting, I should be getting 0.135V from the coil, but that is just a guess. I will know for sure tomorrow. It appears to be higly sensitive. The damping appears to be working nicely. I will post more information tomorrow if needed. Regards. Jón Frímann. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: "Geoff" gmvoeth@........... Date: Thu, 8 May 2008 11:17:28 -0700 Hello ian, Yes, Straight Line Code is almost always faster then is using subroutines or jumps. I notice here your math is all shift and adds Which is in reality all any digital computer does. When you tell a CPU to multiply or divide it only shifts right or left and adds positive or negative numbers. Some decimal numbers can never exactly be reproduced in binary form so there will most times be rounding errors. To reduce the rounding errors the business community dealing in money likes to use BCD " binary coded decimal" TRY to match exactly decimal 0.1 in binary numbers. Sort of like PI it seems to have no end. I wonder out loud here if PI has a number system base whatever that will come out with an end to it. Straight line code is terribly lengthy but the fastest way to go. That is basically what you say here as well as stick to binary math whenever possible. When saving to disk other things need to be considered like exactly how the controller microcode works or handles data and what will be fastest for transfer of data. I have noticed great differences in speed of various programs. The fastest save program I have ever seen relates to a program called SPOTMAU and backs up your system via DOS to an image file in whatever partition It will save at up to 900MB per Minute using FAT32 Drives. That is still much slower then an ATA100 is capable of moving data. I get the feeling that data is written several times over to the same location or things would be much faster than they are. My original question deals more with what technique will save a numerical array fastest to the hard disk drive. Id like to get 100MB/sec which I understand an ATA100 IDE controller & HDD can handle. Best Regards; geoff ----- Original Message ----- From: "ian" To: Sent: Tuesday, May 06, 2008 10:32 AM Subject: Re: Basic Programming Help desired? > Hi, > > I'm not familiar with this flavour of basic but 2 comments: > > Is the for loop meant to be 0 to 32769? Normally it would be 32767 for > 15 bits - I don't know the application for this code. > > When coding loops, I found it better (runs faster) to repeat the code in > the loop and reduce the number of times around the loop, 16 being > optimum. For example: > > FOR A = 0 to 2047 > DATA_1?(A*16 + 0) = ( 65 + (A*16 + 0) MOD 58 ) > DATA_1?(A*16 + 1) = ( 65 + (A*16 + 1) MOD 58 ) > DATA_1?(A*16 + 2) = ( 65 + (A*16 + 2) MOD 58 ) > DATA_1?(A*16 + 3) = ( 65 + (A*16 + 3) MOD 58 ) > DATA_1?(A*16 + 4) = ( 65 + (A*16 + 4) MOD 58 ) > DATA_1?(A*16 + 5) = ( 65 + (A*16 + 5) MOD 58 ) > DATA_1?(A*16 + 6) = ( 65 + (A*16 + 6) MOD 58 ) > DATA_1?(A*16 + 7) = ( 65 + (A*16 + 7) MOD 58 ) > DATA_1?(A*16 + 8) = ( 65 + (A*16 + 8) MOD 58 ) > DATA_1?(A*16 + 9) = ( 65 + (A*16 + 9) MOD 58 ) > DATA_1?(A*16 + 10) = ( 65 + (A*16 + 10) MOD 58 ) > DATA_1?(A*16 + 11) = ( 65 + (A*16 + 11) MOD 58 ) > DATA_1?(A*16 + 12) = ( 65 + (A*16 + 12) MOD 58 ) > DATA_1?(A*16 + 13) = ( 65 + (A*16 + 13) MOD 58 ) > DATA_1?(A*16 + 14) = ( 65 + (A*16 + 14) MOD 58 ) > DATA_1?(A*16 + 15) = ( 65 + (A*16 + 15) MOD 58 ) > NEXT A > DATA_1?(32768) = ( 65 + 32768 MOD 58 ) > DATA_1?(32769) = ( 65 + 32769 MOD 58 ) > > This isn't debugged or known to be syntactically correct. Might be > worth trying though... > > Ian > > Geoff wrote: >> The Following Results Found; >> >> I changed VIRTUAL Array to HUGE >> which I belive keeps everything >> below the DOS 1MB RAM boundary >> and then used a RANDOM instead of a >> BINARY OPEN command. It seems RANDOM >> is best for numbers and BINARY >> is best for Strings if you want to >> do things byte by byte in PowerBasic For DOS. >> EVERYTHING now becomes; >> >> $LIB COM ON >> $LIB FULLFLOAT ON >> $LIB VGA ON >> $ERROR BOUNDS ON >> $ERROR NUMERIC ON >> $ERROR OVERFLOW ON >> $ERROR STACK ON >> $CPU 80386 >> $COM 1024 >> $STRING 32 >> $STACK 2048 >> $SOUND 256 >> $DYNAMIC >> $COMPILE EXE "TEST.EXE" >> $FLOAT NPX >> $OPTIMIZE SPEED >> $EVENT >> $OPTION CNTLBREAK ON >> >> DIM HUGE DATA_1?(0:32769) >> FOR A = 0 to 32769 : DATA_1?(A) = ( 65 + A MOD 58 ) : NEXT A >> FILE1$ = "c:\data\test.dat" >> START1 = TIMER >> OPEN FILE1$ FOR RANDOM AS #1 LEN = 1 >> FOR A?? = 0 to 32769 >> PUT #1,A?? + 1,DATA_1?(A??) >> NEXT A?? >> CLOSE >> STOP1 = TIMER >> IF START1 > STOP1 THEN START1 = START1 + 86400 >> PRINT "FILE CREATION RUNTIME :"; ROUND(( STOP1 - START1 ) , 3 ) >> ' KILL FILE1$ >> SLEEP 3 >> END >> >> Best regards >> geoff >> >> __________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> To leave this list email PSN-L-REQUEST@.............. with the body of >> the message (first line only): unsubscribe >> See http://www.seismicnet.com/maillist.html for more information. >> >> > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: "Geoff" gmvoeth@........... Date: Thu, 8 May 2008 11:30:46 -0700 Mr. Hardy; Thanks for the tip but I already have Power Basic both for Windows and DOS All I really need is to understand fully the programs I am using. It seems the Compiler I am using does not take advantage of the 586 (Pentium) code over the 386. It has been made for backwards compatability. Power Basic is quite good I just need to learn how to properly use it. I can not keep bouncing between various languages or I will spend my whole life and not accomplish any of my own personal goals. One of the biggest problems I see today is that this computer programming world has developed its own Tower Of Bable and you need to have an IQ OVER 100 to master anything involving more than one language. It is a good ol boys club for the gifted and leaves average joe blo layman out in the cold. Best regards; geoff ----- Original Message ----- From: "Dale Hardy" To: Sent: Tuesday, May 06, 2008 3:42 PM Subject: Re: Basic Programming Help desired? > Geoff, > I have been using RapidQ basic. Very ACTIVE user group with strong support > and very helpful > not too far removed from your basic > regards > Dale > http://rapidq.phatcode.net/ > > > > > ----- Original Message ----- > From: "Geoff" > To: > Sent: Tuesday, May 06, 2008 2:15 AM > Subject: Re: Basic Programming Help desired? > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: Kevin Brunt k.brunt@......... Date: Thu, 8 May 2008 20:52:58 +0100 (BST) Hi, This is my first post to the list, so my apologies if I've not got the etiquette right.... What I understand the question to be is, that there is an array of byte-sized integers which are to be written to a disk file exactly as they appear in memory. Having had a look at the manual at www.powerbasic.com what I think you need to use is the form of the PUT statement for binary files... PUT [#] fNum&, [RecPos], Arr() which, I think, will write the whole of the array out as one lump. Kevin >Date: Thu, 8 May 2008 11:30:46 -0700 >From: Geoff >All I really need is to understand fully >the programs I am using. >Power Basic is quite good I just need to learn >how to properly use it. > >I can not keep bouncing between various languages >or I will spend my whole life and not accomplish any >of my own personal goals. > >One of the biggest problems I see today >is that this computer programming world >has developed its own Tower Of Bable >and you need to have an IQ OVER 100 >to master anything involving more than one language. >It is a good ol boys club for the gifted and >leaves average joe blo layman out in the cold. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: SAVING SEISMIC DATA FROM BASIC COMPILED PROGRAM From: "Geoff" gmvoeth@........... Date: Thu, 8 May 2008 13:48:18 -0700 Hello PSN; FYI I have looked more into BSAVE by playing around with it and found it to be the single fastest way to save an array of one byte data. The two files below include everything I know and is yours to play with ( NO GUARANTEES ) all I can tell you is it is the best of all options I have looked at. If you have troubles downloading I will be happy to email you either or both as an attachment. It was able to save an entire 30 minutes of my data generated here at GVA in less than a tic of the timer function = (3600/65540)seconds . http://gmvoeth.home.mchsi.com/testdump.zip http://gmvoeth.home.mchsi.com/testdump.rar BEST regards, geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: "Geoff" gmvoeth@........... Date: Thu, 8 May 2008 13:55:50 -0700 Hello Mr. Brunt ; Yes you are basically correct. But speed of saving the array is the real issue. I have tried just about everything but found nothing faster than using the BSAVE command. I have posted another email with links to the files in question. The given programs in ZIP or RAR form contain all I can tell you. Best regards; geoff ps; I never tried to put a complete array in a single operation. Did not know that was possible. I still think BSAVE will be faster. ----- Original Message ----- From: "Kevin Brunt" To: "psn-l" Sent: Thursday, May 08, 2008 12:52 PM Subject: Re: Basic Programming Help desired? > > Hi, > > This is my first post to the list, so my apologies if I've not got the etiquette > right.... > > What I understand the question to be is, that there is an array of byte-sized integers which are to be written to a disk file > exactly as they appear in memory. > > Having had a look at the manual at www.powerbasic.com what I think you need to use is the form of the PUT statement for binary > files... > > PUT [#] fNum&, [RecPos], Arr() > > which, I think, will write the whole of the array out as one lump. > > Kevin > >>Date: Thu, 8 May 2008 11:30:46 -0700 >>From: Geoff > >>All I really need is to understand fully >>the programs I am using. > >>Power Basic is quite good I just need to learn >>how to properly use it. >> >>I can not keep bouncing between various languages >>or I will spend my whole life and not accomplish any >>of my own personal goals. >> >>One of the biggest problems I see today >>is that this computer programming world >>has developed its own Tower Of Bable >>and you need to have an IQ OVER 100 >>to master anything involving more than one language. >>It is a good ol boys club for the gifted and >>leaves average joe blo layman out in the cold. > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: My lehman type sensor is ready From: Pete Rowe ptrowe@......... Date: Thu, 8 May 2008 14:25:05 -0700 (PDT) WOW, Jon, what a nice job. Let us know how well it works. Pete --- On Thu, 5/8/08, jonfr@......... wrote: > From: jonfr@......... > Subject: My lehman type sensor is ready > To: psn-l@.............. > Date: Thursday, May 8, 2008, 6:28 AM > Hi all >=20 > My lehman type sensor is ready. I hope that it gives me up > to 30 seconds > peroid. But I won't know if that is the case of not > until tomorrow when I > put it online at home. >=20 > Here are two pictures of it. >=20 > http://www.jonfr.com/myndir/v/geology/seismometer/DSC00432.JPG.html > http://www.jonfr.com/myndir/v/geology/seismometer/DSC00433.JPG.html >=20 > If hit by a blank page, just press enter and it should load > properly. >=20 > The mass is about ~1.5kg. The arm is ~70 cm and the mass is > located at the > ~65 cm limit of it. >=20 > I used to speaker magnets as damping magnest. The coil and > the maget are > from Larry. At current setting, I should be getting 0.135V > from the coil, > but that is just a guess. I will know for sure tomorrow. >=20 > It appears to be higly sensitive. The damping appears to be > working nicely. >=20 > I will post more information tomorrow if needed. >=20 > Regards. > J=F3n Fr=EDmann. >=20 > __________________________________________________________ >=20 > Public Seismic Network Mailing List (PSN-L) >=20 > To leave this list email PSN-L-REQUEST@.............. with=20 > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more > information.=0A=0A=0A ______________________________________________= ______________________________________=0ABe a better friend, newshound, and= =0Aknow-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;= _ylt=3DAhu06i62sR8HDtDypao8Wcj9tAcJ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: My lehman type sensor is ready From: ChrisAtUpw@....... Date: Thu, 8 May 2008 17:34:18 EDT In a message dated 2008/05/08, jonfr@......... writes: > My lehman type sensor is ready. I hope that it gives me up to 30 seconds > peroid. But I won't know if that is the case of not until tomorrow when I > put it online at home. Hi Jon, Sorry, but you have made a couple of design mistakes with your Lehman. The coil as shown in the photograph WOULD be sensitive IF the magnet were able to move in the direction of the arm, but NOT at right angles to it! Turn the magnet at right angles and put the coil out to one side. You get a true linear signal as the coil approaches or recedes from the open jaws of the magnet, NOT when the magnet jaws stay at ~the same distance from the coil, moving parallel to the sufaces of the jaws. The setup as shown will only have a very small and non linear sensitivity to small movements. It will give a signal of double the frequency. You definitely need to change it. Putting the magnet on the arm and the coil on the frame allows the arm to be sensitive to changes in the Earth's magnetic field, to surges in the electricity supply cables, to passing trucks and cars.... With the existing setup, you will get quite a noisy signal. It is VASTLY PREFERABLE to put the coil on the arm and the magnet on the base frame! Using a U magnet and a coil will only give about 1/10 the signal that you can get from quad NdFeB magnets on mild steel backing plates. The arm will be sensitive to rocking motions about it's axis. I put a cross bar on the arm close to the mass and a V suspension up to the top hinge to avoid this problem. I can't see from the photo how you have constructed the bottom bearing, or the top suspension. The top suspension is as important as the bottom bearing in getting a long period. Regards, Chris Chapman In a me= ssage dated 2008/05/08, jonfr@......... writes:

My lehman type sensor is ready.= I hope that it gives me up to 30 seconds
peroid. But I won't know if that is the case of not until tomorrow when I put it online at home.


Hi Jon,

       Sorry, but you have made a couple of de= sign mistakes with your Lehman.

       The coil as shown in the photograph WOU= LD be sensitive IF the magnet were able to move in the direction of the arm,= but NOT at right angles to it!
       Turn the magnet at right angles and put= the coil out to one side. You get a true linear signal as the coil approach= es or recedes from the open jaws of the magnet, NOT when the magnet jaws sta= y at ~the same distance from the coil, moving parallel to the sufaces of the= jaws.
       The setup as shown will only have a ver= y small and non linear sensitivity to small movements. It will give a signal= of double the frequency. You definitely need to change it.

       Putting the magnet on the arm and the c= oil on the frame allows the arm to be sensitive to changes in the Earth's ma= gnetic field, to surges in the electricity supply cables, to passing trucks=20= and cars....  With the existing setup, you will get quite a noisy signa= l. It is VASTLY PREFERABLE to put the coil on the arm and the magnet on the=20= base frame!

       Using a U magnet and a coil will only g= ive about 1/10 the signal that you can get from quad NdFeB magnets on mild s= teel backing plates.

       The arm will be sensitive to rocking mo= tions about it's axis. I put a cross bar on the arm close to the mass and a=20= V suspension up to the top hinge to avoid this problem.

       I can't see from the photo how you have= constructed the bottom bearing, or the top suspension. The top suspension i= s as important as the bottom bearing in getting a long period.

       Regards,
 
       Chris Chapman     <= /FONT> Subject: Re: My lehman type sensor is ready From: ian ian@........... Date: Thu, 08 May 2008 22:38:57 +0100 Hi, I was concerned about how you will be able to easily adjust the level of the base. This will need to be done from time to time. Usually there is some adjustment mechanism protruding above the base. Cheers Ian ChrisAtUpw@....... wrote: > In a message dated 2008/05/08, jonfr@......... writes: > >> My lehman type sensor is ready. I hope that it gives me up to 30 seconds >> peroid. But I won't know if that is the case of not until tomorrow when I >> put it online at home. > > > Hi Jon, > > Sorry, but you have made a couple of design mistakes with your > Lehman. > > The coil as shown in the photograph WOULD be sensitive IF the > magnet were able to move in the direction of the arm, but NOT at right > angles to it! > Turn the magnet at right angles and put the coil out to one > side. You get a true linear signal as the coil approaches or recedes > from the open jaws of the magnet, NOT when the magnet jaws stay at > ~the same distance from the coil, moving parallel to the sufaces of > the jaws. > The setup as shown will only have a very small and non linear > sensitivity to small movements. It will give a signal of double the > frequency. You definitely need to change it. > > Putting the magnet on the arm and the coil on the frame allows > the arm to be sensitive to changes in the Earth's magnetic field, to > surges in the electricity supply cables, to passing trucks and > cars.... With the existing setup, you will get quite a noisy signal. > It is VASTLY PREFERABLE to put the coil on the arm and the magnet on > the base frame! > > Using a U magnet and a coil will only give about 1/10 the > signal that you can get from quad NdFeB magnets on mild steel backing > plates. > > The arm will be sensitive to rocking motions about it's axis. I > put a cross bar on the arm close to the mass and a V suspension up to > the top hinge to avoid this problem. > > I can't see from the photo how you have constructed the bottom > bearing, or the top suspension. The top suspension is as important as > the bottom bearing in getting a long period. > > Regards, > > Chris Chapman Hi,

I was concerned about how you will be able to easily adjust the level of the base.  This will need to be done from time to time.  Usually there is some adjustment mechanism protruding above the base.

Cheers

Ian

ChrisAtUpw@....... wrote:
In a message dated 2008/05/08, jonfr@......... writes:

My lehman type sensor is ready. I hope that it gives me up to 30 seconds
peroid. But I won't know if that is the case of not until tomorrow when I
put it online at home.


Hi Jon,

       Sorry, but you have made a couple of design mistakes with your Lehman.

       The coil as shown in the photograph WOULD be sensitive IF the magnet were able to move in the direction of the arm, but NOT at right angles to it!
       Turn the magnet at right angles and put the coil out to one side. You get a true linear signal as the coil approaches or recedes from the open jaws of the magnet, NOT when the magnet jaws stay at ~the same distance from the coil, moving parallel to the sufaces of the jaws.
       The setup as shown will only have a very small and non linear sensitivity to small movements. It will give a signal of double the frequency. You definitely need to change it.

       Putting the magnet on the arm and the coil on the frame allows the arm to be sensitive to changes in the Earth's magnetic field, to surges in the electricity supply cables, to passing trucks and cars....  With the existing setup, you will get quite a noisy signal. It is VASTLY PREFERABLE to put the coil on the arm and the magnet on the base frame!

       Using a U magnet and a coil will only give about 1/10 the signal that you can get from quad NdFeB magnets on mild steel backing plates.

       The arm will be sensitive to rocking motions about it's axis. I put a cross bar on the arm close to the mass and a V suspension up to the top hinge to avoid this problem.

       I can't see from the photo how you have constructed the bottom bearing, or the top suspension. The top suspension is as important as the bottom bearing in getting a long period.

       Regards,
 
       Chris Chapman    
Subject: Fwd: Re: Basic Programming Help desired? From: Kevin Brunt k.brunt@......... Date: Thu, 8 May 2008 22:50:18 +0100 (BST) Hi, I think that you'll find that PUTting a 32768 byte array will be broadly comparable in time to BSAVEing the same array. The timing issues that you have been having are almost certainly due to the manipulation of individual array elements. Your first program was appending each byte to the end of a string one-by-one; I suspect that appending a byte to an N byte string consists of creating a new N+1 byte string, copying the N byte string to it and adding the new byte to the end - the original N byte string is then discarded. The observed delays are due to the repeated copying. Your later program wrote one byte at a time to the file; since there will be a (largely) fixed overhead for each call to PUT, 2^15 calls to PUT takes a lot longer than one call. Incidentally, I've been lurking in the PSN-L archives because I've been working on a PDP-11 (in a museum) that used to be used for seismic processing. The equivalent program to yours in PDP-11 assembler (for the RT-11 operating system) is probably no longer than your BASIC programs, and RT-11 can perform the write-to-disk while the program is filling up the next buffer. (Admittedly, the PDP-11 has 4 6-foot high 19-inch cabinets, each with its own mains lead....) Kevin >Date: Thu, 8 May 2008 13:55:50 -0700 >From: Geoff >Hello Mr. Brunt ; >Yes you are basically correct. >But speed of saving the array is the real issue. >I have tried just about everything but found >nothing faster than using the BSAVE command. >ps; I never tried to put a complete array in a single >operation. Did not know that was possible. >I still think BSAVE will be faster. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: My lehman type sensor is ready From: jonfr@......... Date: Thu, 8 May 2008 18:28:19 -0400 (EDT) Hi Chris The arm moves freely in both direction (Horizontal). But that direction is the assumed default one, rather the vertical one, that also exist on the arm, it was not unexpected behavior as I did see it in the test sensor too. But it doesn't do so easy. I will know tomorrow what movement is the default one. I know about the axis moving strongly to the sides. But the damping magnets limit that movement greatly, it needs a strong force (at least a push of few cm) to move it, that type of push should not happen during a earthquake detection. I did put the coil in the base, rather then it's arm because the coil fits there better, given the U type magnet that I use (this also gives me voltage of 0.135 as it is on the picture). A equipment is magnetic sensitive is going to stay that way regardless of the setup, most setups I have seen show this type of background noise (there plots show it). I will see tomorrow how well this design is going to perform. The helicorder for the sensor is going online after I have done the basic working tests on him. The sensitivity test is going to be when the next big earthquake happens. To see a bigger picture of the seismometer you can choose the maximum size of 1200x1600 in the gallery. I will post better pictures tomorrow of the sensor. Regards. Jón Fríman. > In a message dated 2008/05/08, jonfr@......... writes: > >> My lehman type sensor is ready. I hope that it gives me up to 30 seconds >> peroid. But I won't know if that is the case of not until tomorrow when >> I >> put it online at home. > > Hi Jon, > > Sorry, but you have made a couple of design mistakes with your > Lehman. > > The coil as shown in the photograph WOULD be sensitive IF the > magnet > were able to move in the direction of the arm, but NOT at right angles to > it! > Turn the magnet at right angles and put the coil out to one side. > You > get a true linear signal as the coil approaches or recedes from the open > jaws > of the magnet, NOT when the magnet jaws stay at ~the same distance from > the > coil, moving parallel to the sufaces of the jaws. > The setup as shown will only have a very small and non linear > sensitivity to small movements. It will give a signal of double the > frequency. You > definitely need to change it. > > Putting the magnet on the arm and the coil on the frame allows the > arm > to be sensitive to changes in the Earth's magnetic field, to surges in the > electricity supply cables, to passing trucks and cars.... With the > existing > setup, you will get quite a noisy signal. It is VASTLY PREFERABLE to put > the coil > on the arm and the magnet on the base frame! > > Using a U magnet and a coil will only give about 1/10 the signal > that > you can get from quad NdFeB magnets on mild steel backing plates. > > The arm will be sensitive to rocking motions about it's axis. I put > a > cross bar on the arm close to the mass and a V suspension up to the top > hinge > to avoid this problem. > > I can't see from the photo how you have constructed the bottom > bearing, or the top suspension. The top suspension is as important as the > bottom > bearing in getting a long period. > > Regards, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Another New Lehman From: tchannel1@............ Date: Thu, 8 May 2008 21:38:31 -0600 Hi Folks, I have also built another Lehman. I was disappointed that I = did not get the 6.8M Japan May 7. It has a proven hinge, top and bottom. Proven in that I have used this = approach before several times and it was successful. ball bearing for = the bottom and wire for the top. The period is set at 20 seconds, and this was difficult, but I got it. The coil is 3600 turn and magnets are also proven design. The boom is pointing East West. The damping is as expected. I did get this earthquake on two other sensors one vertical and one tilt = meter (just a 48" pendulum) swinging East West. Q. Could it be over damped? Q. With the period at 20 second, could this be too high? Too high for = this earthquake? Q. Could it be the base on which the sensor is position? It is carpet, = on top of the carpet are concrete blocks, SS pads, and the sensor set on = these. I have used this on many other short period sensor, and it = works for those. I see nothing wrong. It does record all the road construction, and my = movements around the room. Thanks for you suggestions. Ted
Hi Folks,  I have also built = another=20 Lehman.  I was disappointed that I did not get the 6.8M Japan May=20 7.
 
It has a proven hinge, top and = bottom.  =20 Proven in that I have used this approach before several times and it was = successful.  ball bearing for the bottom and wire for the = top.
 
The period is set at 20 seconds, and = this was=20 difficult, but I got it.
The coil is 3600 turn and magnets are = also proven=20 design.
 
The boom is pointing East = West.
The damping is as = expected.
 
I did get this earthquake on two other = sensors one=20 vertical and one tilt meter (just a 48" pendulum) swinging East=20 West.
 
Q.  Could it be over = damped?
Q.  With the period at 20 second, = could this=20 be too high? Too high for this earthquake?
Q.  Could it be the base on which = the sensor=20 is position?  It is carpet, on top of the carpet are concrete = blocks, SS=20 pads, and the sensor set on these.   I have used this on many = other=20 short period sensor, and it works for those.
 
I see nothing wrong.   It = does record all=20 the road construction, and my movements around the room.
 
Thanks for you = suggestions.
 
Ted
Subject: Re: Another New Lehman From: ChrisAtUpw@....... Date: Fri, 9 May 2008 00:16:06 EDT In a message dated 2008/05/09, tchannel1@............ writes: > It has a proven hinge, top and bottom. Proven in that I have used this > approach before several times and it was successful. ball bearing for the > bottom and wire for the top. Hi Ted, What have you used for the hard counterface for the ball bearing? I use either a polished tungaten carbide triangular tool tip or a SS scalpel blade, stuck in place with acrylic glue. > The period is set at 20 seconds, and this was difficult, but I got it. This should not be difficult. > The coil is 3600 turn and magnets are also proven design. > The boom is pointing East West. > The damping is as expected. > I did get this earthquake on two other sensors one vertical and one tilt > meter (just a 48" pendulum) swinging East West. > > Q. Could it be over damped? > Q. With the period at 20 second, could this be too high? Too high for this > earthquake? > Q. Could it be the base on which the sensor is position? It is carpet, on > top of the carpet are concrete blocks, SS pads, and the sensor set on these. > I have used this on many other short period sensor, and it works for those. > > I see nothing wrong. It does record all the road construction, and my > movements around the room. You can easily check the damping. Push the boom 10 mm to one side with a pencil or similar and release it. It should swing about 1/2 mm past the zero position. I use a magnifying glass and a transparent ruler to observe this. You should have seen the Love waves. Regards, Chris Chapman In a me= ssage dated 2008/05/09, tchannel1@............ writes:

It has a proven hinge, top and=20= bottom.   Proven in that I have used this approach before several=20= times and it was successful.  ball bearing for the bottom and wire for=20= the top.


Hi Ted,

       What have you used for the hard counter= face for the ball bearing? I use either a polished tungaten carbide triangul= ar tool tip or a SS scalpel blade, stuck in place with acrylic glue.<= FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff"= SIZE=3D3 PTSIZE=3D12 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0">

The period is set at 20 second= s, and this was difficult, but I got it.


       This should not be difficult.

The coil is 3600 turn and magn= ets are also proven design.
The boom is pointing East West.
The damping is as expected.
I did get this earthquake on two other sensors one vertical and one tilt me= ter (just a 48" pendulum) swinging East West.

Q.  Could it be over damped?
Q.  With the period at 20 second, could this be too high? Too high for= this earthquake?
Q.  Could it be the base on which the sensor is position?  It is=20= carpet, on top of the carpet are concrete blocks, SS pads, and the sensor se= t on these.   I have used this on many other short period sensor,=20= and it works for those.

I see nothing wrong.   It does record all the road construction,=20= and my movements around the room.


       You can easily check the damping. Push=20= the boom 10 mm to one side with a pencil or similar and release it. It shoul= d swing about 1/2 mm past the zero position. I use a magnifying glass and a=20= transparent ruler to observe this.

       You should have seen the Love waves.
       Regards,

       Chris Chapman Subject: Re: Fwd: Re: Basic Programming Help desired? From: ian ian@........... Date: Fri, 09 May 2008 07:42:12 +0100 Hi Kevin, I used the inline code example (I posted earlier) on PDP 11 computers. The machines were actually real-time LSI-11 SBCs running Micropower Pascal/assembler developed on a pdp 11 (with twin rlo2 disks) development machine. The application was to control, read and process images from what was then (1986) the worlds highest resolution (3596 pixels) astronomy infra-red camera, cooled to -200C on, what was then, the worlds largest infra-red telescope (UKIRT - 3.8m) in Hawai'i. I wrote the time critical parts in assembler and the rest in Pascal. As for the current PSN problem, I would suggest scrapping basic and windows and going for a Linux machine and program in C. Cheers Ian > > Incidentally, I've been lurking in the PSN-L archives because I've been working on a PDP-11 (in a museum) that used to be used for seismic processing. The equivalent program to yours in PDP-11 assembler (for the RT-11 operating system) is probably no longer than your BASIC programs, and RT-11 can perform the write-to-disk while the program is filling up the next buffer. (Admittedly, the PDP-11 has 4 6-foot high 19-inch cabinets, each with its own mains lead....) > > Kevin > > >> Date: Thu, 8 May 2008 13:55:50 -0700 >> From: Geoff >> > > >> Hello Mr. Brunt ; >> Yes you are basically correct. >> But speed of saving the array is the real issue. >> I have tried just about everything but found >> nothing faster than using the BSAVE command. >> > > >> ps; I never tried to put a complete array in a single >> operation. Did not know that was possible. >> I still think BSAVE will be faster. >> > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > > Hi Kevin,

I used the inline code example (I posted earlier) on PDP 11 computers.  The machines were actually real-time LSI-11 SBCs running Micropower Pascal/assembler developed on a pdp 11 (with twin rlo2 disks) development machine.  The application was to control, read and process images from what was then (1986) the worlds highest resolution (3596 pixels) astronomy infra-red camera, cooled to -200C on, what was then, the worlds largest infra-red telescope (UKIRT - 3.8m) in Hawai'i.

I wrote the time critical parts in assembler and the rest in Pascal.  As for the current PSN problem, I would suggest scrapping basic and windows and going for a Linux machine and program in C.

Cheers

Ian

Incidentally, I've been lurking in the PSN-L archives because I've been working on a PDP-11 (in a museum) that used to be used for seismic processing. The equivalent program to yours in PDP-11 assembler (for the RT-11 operating system) is probably no longer than your BASIC programs, and RT-11 can perform the write-to-disk while the program is filling up the next buffer. (Admittedly, the PDP-11 has 4 6-foot high 19-inch cabinets, each with its own mains lead....)

Kevin

  
Date: Thu, 8 May 2008 13:55:50 -0700
From: Geoff <gmvoeth@...........>  
    

  
Hello Mr. Brunt ;
Yes you are basically correct.
But speed of saving the array is the real issue.
I have tried just about everything but found
nothing faster than using the BSAVE command.
    

  
ps; I never tried to put a complete array in a single
operation. Did not know that was possible.
I still think BSAVE will be faster.
    
__________________________________________________________

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To leave this list email PSN-L-REQUEST@.............. with 
the body of the message (first line only): unsubscribe
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Subject: Re: Basic Programming Help desired? From: Kevin Brunt k.brunt@......... Date: Fri, 9 May 2008 11:15:36 +0100 (BST) Hi, While I am not going to argue against the "unrolling" of the code within a loop, my take on it is that it is something that a good optimising compiler will do for you. In your example, I suspect that the cost of the repeated "multiply-by-sixteen" operations would lose a lot of the time saved by reducing the amount of "iteration overhead". I don't think that a "Linux plus C" approach will serve Geoff's purpose. Apart from the fact that he obviously would rather get on with the seismology, rather than learning another programming language, he's wanting to run his data capture system on a low-spec machine (retired from other uses, I suspect). Kevin ---- Original message ---- >Date: Fri, 09 May 2008 07:42:12 +0100 >From: ian ian@... > I used the inline code example (I posted earlier) on > PDP 11 computers. > I wrote the time critical parts in assembler and the > rest in Pascal. As for the current PSN problem, I > would suggest scrapping basic and windows and going > for a Linux machine and program in C. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: ian ian@........... Date: Fri, 09 May 2008 16:04:25 +0100 Hi, a good compiler might well optimise it out but developing fast code involves a bit of trial and error, which is why I suggested trying it. If it doesn't give a useful gain, then just take it out again. Compilers are mysterious beasts. I suspect that Basic compilers will be amongst the most bestial. :-) I can understand the initial deterrent of migrating to another system but if you use the right tools then you'll get the best results. When Linux first came out, I ran it on an old 486 machine. These days, the slowest Linux machine I'm running is a 586 220 MHz - it just sits there, month after month, doing its job! Ian Kevin Brunt wrote: > Hi, > > While I am not going to argue against the "unrolling" of the code within a loop, my take on it is that it is something that a good optimising compiler will do for you. In your example, I suspect that the cost of the repeated "multiply-by-sixteen" operations would lose a lot of the time saved by reducing the amount of "iteration overhead". > > I don't think that a "Linux plus C" approach will serve Geoff's purpose. Apart from the fact that he obviously would rather get on with the seismology, rather than learning another programming language, he's wanting to run his data capture system on a low-spec machine (retired from other uses, I suspect). > > Kevin > > ---- Original message ---- > >> Date: Fri, 09 May 2008 07:42:12 +0100 >> From: ian ian@... >> > > >> I used the inline code example (I posted earlier) on >> PDP 11 computers. >> > > >> I wrote the time critical parts in assembler and the >> rest in Pascal. As for the current PSN problem, I >> would suggest scrapping basic and windows and going >> for a Linux machine and program in C. >> > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > > Hi,

a good compiler might well optimise it out but developing fast code involves a bit of trial and error, which is why I suggested trying it.  If it doesn't give a useful gain, then just take it out again.  Compilers are mysterious beasts.  I suspect that Basic compilers will be amongst the most bestial.  :-)

I can understand the initial deterrent of migrating to another system but if you use the right tools then you'll get the best results.  When Linux first came out, I ran it on an old 486 machine.  These days, the slowest Linux machine I'm running is a 586 220 MHz - it just sits there, month after month, doing its job!

Ian

Kevin Brunt wrote: 
Hi,

While I am not going to argue against the "unrolling" of the code within a loop, my take on it is that it is something that a good optimising compiler will do for you. In your example, I suspect that the cost of the repeated "multiply-by-sixteen" operations would lose a lot of the time saved by reducing the amount of "iteration overhead".

I don't think that a "Linux plus C" approach will serve Geoff's purpose. Apart from the fact that he obviously would rather get on with the seismology, rather than learning another programming language, he's wanting to run his data capture system on a low-spec machine (retired from other uses, I suspect).

Kevin

---- Original message ----
  
Date: Fri, 09 May 2008 07:42:12 +0100
From: ian ian@...
    

  
  I used the inline code example (I posted earlier) on
  PDP 11 computers.
    

  
  I wrote the time critical parts in assembler and the
  rest in Pascal.  As for the current PSN problem, I
  would suggest scrapping basic and windows and going
  for a Linux machine and program in C.
    
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To leave this list email PSN-L-REQUEST@.............. with 
the body of the message (first line only): unsubscribe
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Subject: Re: Re: Basic Programming Help desired? From: "Geoff" gmvoeth@........... Date: Fri, 9 May 2008 14:28:49 -0700 Hello Cruel World; I have learned by simply changing my arrays from Virtual ( EMS MEMORY ) to HUGE ( REAL MODE UNDER 1MB ) all my routines relating to arrays is faster by like 17X faster. There is something rotten in denmark in regards to memory management over 1 MB. I got this fft routine that now completes 128 lines of results in one second instead of 17 seconds. Now I have this PowerBasic for Windows that I have never tried but understand is faster code but it will not run under DOS as i remember and you need to make DLLs and the like which are foreign to my way of thinking. Why the heck dont the world of science beat the world of business into a corner and create a decent operating system for science oriented persons. We do not need all that security garbage like the money people do ( meaning Protected MODE ). geoff ----- Original Message ----- From: "Kevin Brunt" To: "psn-l" Sent: Thursday, May 08, 2008 2:50 PM Subject: Fwd: Re: Basic Programming Help desired? > > Hi, > > I think that you'll find that PUTting a 32768 byte array will be broadly comparable in time to BSAVEing the same array. > > The timing issues that you have been having are almost certainly due to the manipulation of individual array elements. Your first > program was appending each byte to the end of a string one-by-one; I suspect that appending a byte to an N byte string consists of > creating a new N+1 byte string, copying the N byte string to it and adding the new byte to the end - the original N byte string is > then discarded. The observed delays are due to the repeated copying. > > Your later program wrote one byte at a time to the file; since there will be a (largely) fixed overhead for each call to PUT, 2^15 > calls to PUT takes a lot longer than one call. > > Incidentally, I've been lurking in the PSN-L archives because I've been working on a PDP-11 (in a museum) that used to be used for > seismic processing. The equivalent program to yours in PDP-11 assembler (for the RT-11 operating system) is probably no longer > than your BASIC programs, and RT-11 can perform the write-to-disk while the program is filling up the next buffer. (Admittedly, > the PDP-11 has 4 6-foot high 19-inch cabinets, each with its own mains lead....) > > Kevin > >>Date: Thu, 8 May 2008 13:55:50 -0700 >>From: Geoff > >>Hello Mr. Brunt ; >>Yes you are basically correct. >>But speed of saving the array is the real issue. >>I have tried just about everything but found >>nothing faster than using the BSAVE command. > >>ps; I never tried to put a complete array in a single >>operation. Did not know that was possible. >>I still think BSAVE will be faster. > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: My lehman type sensor is ready From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sat, 10 May 2008 00:11:47 +0000 Hi all The lehman type sensor is up and running. However I have found one bad bug in it. Where the arm as attached to the arm where the mass is. I need to make it shorter (I think, at least so I can get it to hold the mass up properly) and attach it to the mass arm it self to hold it up. But the current attachment can't hold up the mass, that did destory the hoding inside of it. The second issue that I might have is that I am not sure if the damping is correct or not. Using Winquake FFT feature it appears that the seismomter has a natrual frequancy of around 1Hz but it goes down to 10 seconds. This is a second bug that I also need to fix somehow. As I am looking for up to 30 second period. I hope to fix the first bug on monday, I might also do some other modifactions to the sensor to make it more sensitive. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: The UK, "Evolution" brand chop saw for our seismometer steel and other metals/uses From: "meredith lamb" paleoartifact@......... Date: Fri, 9 May 2008 20:53:34 -0600 Hi all, This seems like a very interesting fast cutting 14" circular cut-off or chop saw, as it supposedly cuts 1/4" thick unhardened steel; which could be quite useful for those home hard to do projects like straight cutting the steel plates for the neodymium pickup magnets and/or seismometer dampening. There is some amazing online videos of its use in action. Amazing is a very common term I see from a variety of sellers on their various web sites. Specifically its the (blue label) steel cutting blade, but other blades can be used for other metals. They also have another blue label blade for thin steel sheet metal. The blades have 1" diameter bores, which might fit other saws, but, the "other chop saw" motor speed needs to around 1500rpm via gear reduction. There is a web variety of sellers. Even Sears (USA) sells "online only" the RAGE 2 chop saw; but unfortunately without the best (blue label) steel blade, at a web low price of $279.00...you would need to get the "best" blue label steel blade via other sellers on the web. Sears also sells the RAGE 3 multipurpose compound sliding 10" miter saw for $299.99; without again, the "best" (blue label) steel blade. The common shown orange label blades seem to be general multi-purpose metal cutting blades. The RAGE 3 blade turns at 2500 rpm, but only lasts roughly ~1/4 the cuts of the RAGE 2; but might be more useful for other projects with all its more extensive setup options. A good starting reference is below, and also shows a variety of metal blades: http://www.evolutiononlineshop.com/store/index.cfm Specifically the RAGE 2 looks like it could cut a max straight 7" width (90 degree) flat plate of 1/4" steel. The RAGE 3 looks like it could cut a little over a (90degree) 11" width. Lesser angles=lesser length cuts. From what I read it cuts straight true cuts; something you will absolutely NOT get on common abrasive metal cutting chop saws. Most machinists prefer the old reliable band saws; but they are usually a lot more expensive and alot bigger in overall size. A real potential negative I read is that the operator might have to "hold back" the chop saw a bit, as it wants to dig in faster than is normally safe. Some chop saw brands have some means of downward tension/pressure adjustments for their machines. If someone here already uses such I would be very interested in their assessment or notes. Meredith Lamb Hi all,

This seems like a very interesting fast cutting 14" circular cut-off or chop saw, as it supposedly cuts 1/4"
thick unhardened steel; which could be quite useful for those home hard to do projects like straight cutting the steel
plates for the neodymium pickup magnets and/or seismometer dampening.  There is some amazing online
videos of its use in action.  Amazing is a very common term I see from a variety of sellers on their various
web sites.

Specifically its the (blue label) steel cutting blade, but other blades can be used for other metals.
They also have another blue label blade for thin steel sheet metal.   The blades have 1" diameter
bores, which might fit other saws, but, the "other chop saw" motor speed needs to around 1500rpm
via gear reduction.

There is a web variety of sellers.  Even Sears (USA) sells "online only" the RAGE 2 chop saw; but unfortunately
without the best (blue label) steel blade, at a web low price of $279.00...you would need to get the "best" blue
label steel blade via other sellers on the web.   Sears also sells the RAGE 3 multipurpose compound sliding 10"
miter saw for $299.99; without again, the "best" (blue label) steel blade.  The common shown orange label blades seem
to be general multi-purpose metal cutting blades.   The RAGE 3 blade turns at 2500 rpm, but only lasts roughly
~1/4 the cuts of the RAGE 2; but might be more useful for other projects with all its more extensive setup options.

A good starting reference is below, and also shows a variety of metal blades:
http://www.evolutiononlineshop.com/store/index.cfm

Specifically the RAGE 2 looks like it could cut a max straight 7" width (90 degree) flat plate of 1/4" steel.   The
RAGE 3 looks like it could cut a little over a (90degree) 11" width.  Lesser angles=lesser length cuts.

From what I read it cuts straight true cuts; something you will absolutely NOT get on common abrasive metal
cutting chop saws.  Most machinists prefer the old reliable band saws; but they are usually a lot more expensive and
alot bigger in overall size.

A real potential negative I read is that the operator might have to "hold back" the chop saw a bit, as it wants
to dig in faster than is normally safe.  Some chop saw brands have some means of downward tension/pressure
adjustments for their machines.

If someone here already uses such I would be very interested in their assessment or notes.

Meredith Lamb

 


Subject: Re: Basic Programming Help desired? From: "Geoff" gmvoeth@........... Date: Sat, 10 May 2008 00:08:33 -0700 another programming language, he's wanting to run his data capture system on a low-spec machine (retired from other uses, I suspect). > > Kevin Nope, I used to run my program on a TRS Laptop With a 10MHz CPU (Z80 sound familiar ?) then some burglars stole that machine from my folks house which the insurance company replaced with Toshiba Satellite 205CDS and since the late 1990s (I think) I have been using that exclusively for seismic stuff. It has never been retired from anything I am aware of. Its RTC is terrible looses 1 second ( slow) every 4 hours or so Without a ring counter the WWV reception is so horrible Id have no decent calibration indicator for times. I can not compliment the Japanese in the calibration of their digital Quartz whatevers. Obviously this machine was never calibrated at operating temperatures. Although it keeps bad time it IS a rugged machine. In ruggedness it matches an old timex watch commercial. If I could recommend something to all manufacturers of electronic devices it would be to calibrate their quartz clocks properly and build everything within a faraday shield. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Basic Programming Help desired? From: Mike Price seapsn@........ Date: Sat, 10 May 2008 02:08:30 -0700 Regarding clocks in DOS (and all other OSes): The RTC is used to set the operating system clock only at boot. After that, the OS keeps time from its own timer driven by a periodic interrupt. Since interrupts can be blocked (e.g. by other interrupts), the OS must take special care to ensure an accurate time of day clock. DOS is notorious for failing to do this properly as are most versions of windows.One hack is to sync the OS clock with the RTC clock periodically (by calling the clock program from a script). Another is to run ntp (not possible on a singly threaded OS like DOS). If you need an accurate clock in DOS, there are routines available that can read the RTC clock directly and ignore the DOS clock. Regarding memory management in DOS. The PC can directly (easily) address only 640KB of memory. This was a HW restriction of the original PC, preserved in DOS despite CPU improvements. Extended memory can provide many megabytes, but memory accesses are slower since all accesses are indirect (an address register is loaded, then memory is accessed). The compiler takes care of memory management behind the scenes, but you'll get better performance if the code and data fit into the 640KB. Given a Pentium, Windows or Linux will implement a linear memory model and give better performance for large arrays (generally). Mike Geoff wrote: > another programming language, he's wanting to run his data capture > system on a low-spec machine (retired from other uses, I suspect). >> >> Kevin > > Nope, I used to run my program on a TRS Laptop With a > 10MHz CPU (Z80 sound familiar ?) then some burglars > stole that machine from my folks house which the > insurance company replaced with Toshiba Satellite > 205CDS and since the late 1990s (I think) I have been using that > exclusively for seismic stuff. > It has never been retired from anything I am aware of. > Its RTC is terrible looses 1 second ( slow) every > 4 hours or so Without a ring counter the WWV reception > is so horrible Id have no decent calibration indicator > for times. I can not compliment the Japanese > in the calibration of their digital Quartz whatevers. > Obviously this machine was never calibrated at operating > temperatures. Although it keeps bad time it IS a rugged machine. > In ruggedness it matches an old timex watch commercial. > If I could recommend something to all manufacturers > of electronic devices it would be to calibrate their > quartz clocks properly and build everything within a faraday shield. > > > > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of > the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Unusual oscillations From: "Thomas Dick" dickthomas01@............. Date: Sat, 10 May 2008 08:24:04 -0500 Here in southern Indiana I have seen peaks in the area of .233Hz/4.338period for about twenty four hours. It is most pronounced on the E-W Lehman but even visible on the AS-1. Weather is quiet right now: little wind or fronts around -- even foggy. Has anyone else noticed this on your units? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Unusual oscillations From: ChrisAtUpw@....... Date: Sat, 10 May 2008 10:02:05 EDT In a message dated 2008/05/10, dickthomas01@............. writes: > Here in southern Indiana I have seen peaks in the area of > .233Hz/4.338period > for about twenty four hours. Hi Tom, Could these be Pacific Microseisms? They tend to be of shorter period than the Atlantic ones at about 6 seconds. Regards, Chris Chapman In a me= ssage dated 2008/05/10, dickthomas01@............. writes:

Here in southern Indiana I have= seen peaks in the area of .233Hz/4.338period
for about twenty four hours.


Hi Tom,

       Could these be Pacific Microseisms? The= y tend to be of shorter period than the Atlantic ones at about  6 secon= ds.

       Regards,

       Chris Chapman Subject: Re: Unusual oscillations From: Larry Conklin lconklin@............ Date: Sat, 10 May 2008 10:05:44 -0400 Hi Thomas, Very probably, what you are seeing is microseisms. I have also been seeing this activity on my horizontal SG sensor for the last half a day or so, and they also are showing up strongly on the web site run by Lamont-Doherty Earth Observatory. My understanding is that the mechanism that produces these waves isn't completely understood, but that they are believed to be caused by ocean waves resulting from strong storms. Being able to see them is a good thing. It's a sign that your sensor is working well. Larry Conklin Liverpool, NY Thomas Dick wrote: > Here in southern Indiana I have seen peaks in the area of > .233Hz/4.338period for about twenty four hours. It is most pronounced on > the E-W Lehman but even visible on the AS-1. Weather is quiet right now: > little wind or fronts around -- even foggy. Has anyone else noticed this > on your units? > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of > the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: My lehman type sensor is ready From: "Gary Lindgren" gel@................. Date: Sat, 10 May 2008 11:40:21 -0700 Hello Jon, I'm in the process now in building my first Lehman, but here are my observations looking at the picture.=20 1. I agree with the comments of Chris. I highly recommend going to the Chapman magnet assembly for the sensor. Your coil seems too small in diameter and the highest flux area of the magnet is over the coil wires = that are in the direction of the magnet motion. In order for a voltage to be generated, you need to have the wires perpendicular to the magnet = motion. The problem with the small coil is that a voltage is generated from the = flux field broken on the far side of one polarity and then the opposite = polarity voltage is generated on the near side coil wires. The 2 voltages will = then offset each other. If you want to use your coil and magnet, then rotate = the magnet 90 degrees and then move the coil so that only one side of the = coil moves through the magnet flux field. You can purchase Neodymium magnets = from http://www.kjmagnetics.com/ They are very reasonable in cost. 2. The damping is probably not working at all. It looks as if you took = the speaker magnets and have either the north poles opposite or the south = poles opposite each other. If this is what you have then you have zero flux in = the middle where you have the damping plate. You must have a flux field set = up. That means that a north pole must face a south pole magnet. If you have opposite poles facing each other then you need to have a better return = flux path. Now you have only the 1/4 inch bolts are the return path. You = probably have magnetic flux spread all over. Think of your magnet assembly just = like an electrical circuit. The 1/4 inch bolts are just like a high = resistance path. Again go with the Chapman magnet assembly. Gary=20 -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... = On Behalf Of J=F3n Fr=EDmann Sent: Friday, May 09, 2008 5:12 PM To: psn-l@.............. Subject: Re: My lehman type sensor is ready Hi all The lehman type sensor is up and running. However I have found one bad bug in it. Where the arm as attached to the arm where the mass is. I need to make it shorter (I think, at least so I can get it to hold the mass up properly) and attach it to the mass arm it self to hold it up. But the current attachment can't hold up the mass, that did destory the hoding inside of it. The second issue that I might have is that I am not sure if the damping is correct or not. Using Winquake FFT feature it appears that the seismomter has a natrual frequancy of around 1Hz but it goes down to 10 seconds. This is a second bug that I also need to fix somehow. As I am looking for up to 30 second period. I hope to fix the first bug on monday, I might also do some other modifactions to the sensor to make it more sensitive. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: My lehman type sensor is ready From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sat, 10 May 2008 19:45:25 +0000 Hi Gary 1. The magnets are an easy fix. If I turn the silver side on vs the dark side I get N/S configuration. However, part of the daming issue appears to be the arm that holds up the boom, it isn't holding it properly so the boom viprates more then it needs to when a signal passes trugh it. That issue is going to be fixed when I attach the arm directly with the boom. This is steel, not iron. But the base is made out of aluminum. 2. This issue is going to be resolved on 13th of May I hope. Then I am going to rotate the magnet 90 degress and put the coil on the boom. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Frequencies From: tchannel1@............ Date: Sat, 10 May 2008 16:07:27 -0600 Hi Folks, With some help from many of you, I understand how one loses = the signals LONGER than your sensor natural period. ie If you sensors = period is 10 seconds it will lose (attenuate) the longer frequencies at = a rate of 12 decibels per octave. I think I understand that part. =20 But want about the opposite, say the sensors is 10 second, how does it = lose or does it lose shorter frequencies, like 2, 4 or 6 seconds waves? My new Lehman is set at 20 seconds, will it pick up 1, 2, and 3 seconds = waves? Thanks, Ted
Hi Folks,  With some help from = many of you, I=20 understand how one loses the signals LONGER than your sensor natural=20 period.  ie  If you sensors period is 10 seconds it will = lose =20 (attenuate) the longer frequencies at a rate of 12 decibels per=20 octave.   I think I understand that part. 
 
But want about the opposite, say the = sensors is 10=20 second, how does it lose or does it lose shorter frequencies, like 2, 4 = or 6=20 seconds waves?
 
My new Lehman is set at 20 seconds, = will it pick up=20 1, 2, and 3 seconds waves?
 
Thanks, Ted
Subject: Re: Frequencies From: ChrisAtUpw@....... Date: Sat, 10 May 2008 19:16:43 EDT In a message dated 2008/05/10, tchannel1@............ writes: > But want about the opposite, say the sensors is 10 second, how does it lose > or does it lose shorter frequencies, like 2, 4 or 6 seconds waves? Hi Ted, The output should be flat with velocity from the natural period right up to the frequency set by the low pass filter on your amplifier. This is probably 10 Hz. Regards, Chris Chapman In a me= ssage dated 2008/05/10, tchannel1@............ writes:

But want about the opposite, sa= y the sensors is 10 second, how does it lose or does it lose shorter frequen= cies, like 2, 4 or 6 seconds waves?


Hi Ted,

       The output should be flat with velocity= from the natural period right up to the frequency set by the low pass filte= r on your amplifier. This is probably 10 Hz.

       Regards,

       Chris Chapman Subject: Re: Unusual oscillations From: "Geoff" gmvoeth@........... Date: Sat, 10 May 2008 17:14:27 -0700 Yes, in my case it seems to preceed a weather front. ----- Original Message ----- From: "Thomas Dick" To: Sent: Saturday, May 10, 2008 6:24 AM Subject: Unusual oscillations > Here in southern Indiana I have seen peaks in the area of .233Hz/4.338period > for about twenty four hours. It is most pronounced on the E-W Lehman but > even visible on the AS-1. Weather is quiet right now: little wind or fronts > around -- even foggy. Has anyone else noticed this on your units? > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Frequencies From: "Geoff" gmvoeth@........... Date: Sat, 10 May 2008 17:18:06 -0700 Periods shorter meaning a higher freq should be ok with a 10 sec sensor or so I understand since the mass is at rest for freqs above resonance. The mass moves below resonance and thats why you loose sensitivity. Or so i understand. ----- Original Message ----- From: To: "psn" Sent: Saturday, May 10, 2008 3:07 PM Subject: Frequencies Hi Folks, With some help from many of you, I understand how one loses the signals LONGER than your sensor natural period. ie If you sensors period is 10 seconds it will lose (attenuate) the longer frequencies at a rate of 12 decibels per octave. I think I understand that part. But want about the opposite, say the sensors is 10 second, how does it lose or does it lose shorter frequencies, like 2, 4 or 6 seconds waves? My new Lehman is set at 20 seconds, will it pick up 1, 2, and 3 seconds waves? Thanks, Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Unusual oscillations From: "Thomas Dick" dickthomas01@............. Date: Sun, 11 May 2008 10:22:39 -0500 I guess Geoff is right. The intensity has increased. I have two lows passing; one to the north and the other to the south -- even tornadoes to my south. Local winds sustained above 10 mpn ... gusting to 25 mph with occasional gusts above 35 mph. Electricity was off briefly too. ----- Original Message ----- From: "Geoff" To: Sent: Saturday, May 10, 2008 7:14 PM Subject: Re: Unusual oscillations > Yes, in my case it seems to preceed a weather front. > > ----- Original Message ----- > From: "Thomas Dick" > To: > Sent: Saturday, May 10, 2008 6:24 AM > Subject: Unusual oscillations > > >> Here in southern Indiana I have seen peaks in the area of >> .233Hz/4.338period for about twenty four hours. It is most pronounced on >> the E-W Lehman but even visible on the AS-1. Weather is quiet right now: >> little wind or fronts around -- even foggy. Has anyone else noticed this >> on your units? __________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> To leave this list email PSN-L-REQUEST@.............. with the body of >> the message (first line only): unsubscribe >> See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of the > message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: China Quake From: ian ian@........... Date: Mon, 12 May 2008 08:36:19 +0100 Hi, getting enormous signals from the China quake here in Scotland. See http://www.iasmith.com . Ian __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: China Quake From: ChrisAtUpw@....... Date: Mon, 12 May 2008 08:19:34 EDT In a message dated 2008/05/12, ian@........... writes: > getting enormous signals from the China quake here in Scotland. See > http://www.iasmith.com HI Ian, Likewise! I get a time out error when I try to call your website as listed above. Regards, Chris Chapman In a me= ssage dated 2008/05/12, ian@........... writes:

getting enormous signals from t= he China quake here in Scotland.  See
http://www.iasmith.com


HI Ian,

       Likewise!

       I get a time out error when I try to ca= ll your website as listed above.

       Regards,

       Chris Chapman Subject: Re: China Quake From: ian ian@........... Date: Mon, 12 May 2008 13:24:33 +0100 Hi, I can still get my web page to respond from here. It's hosted in the states... It's also on the psn site: http://www.webtronics.com/cgi-dos/makegif.exe?/quakes/0805/080512.063616.hd1.psn though the P & S markers have gone for a walk! Ian ChrisAtUpw@....... wrote: > In a message dated 2008/05/12, ian@........... writes: > >> getting enormous signals from the China quake here in Scotland. See >> http://www.iasmith.com > > > HI Ian, > > Likewise! > > I get a time out error when I try to call your website as > listed above. > > Regards, > > Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: China Quake From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 12 May 2008 12:33:41 +0000 Hi all I did record the China earthquake on all of my sensors. The signal did appear clearly here in Iceland. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Map of the tectonic plates From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 12 May 2008 22:53:38 +0000 Hi all Here is a map with the tectonic plates of the earth. Along with good details of other major fault lines. http://www.globalchange.umich.edu/globalchange1/current/lectures/evolving_e= arth/tectonic_map.jpg Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: China Quake From: "Geoff" gmvoeth@........... Date: Mon, 12 May 2008 16:12:21 -0700 Roger That, here's the picture from [GVA] SPZ http://gmvoeth.home.mchsi.com/gva_20080512_06422611_UTC.psn.gif ----- Original Message ----- From: "ian" To: Sent: Monday, May 12, 2008 12:36 AM Subject: China Quake > Hi, > > getting enormous signals from the China quake here in Scotland. See > http://www.iasmith.com . > > Ian > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Correction to old message From: "Geoff" gmvoeth@........... Date: Thu, 15 May 2008 09:51:26 -0700 "Nope, I used to run my program on a TRS Laptop With a 10MHz CPU (Z80 sound familiar ?) then some burglars stole that machine from my folks house which the insurance company replaced with Toshiba Satellite 205CDS and since the late 1990s (I think) I have been using that exclusively for seismic stuff." NOT Z80 but rather VIC-20. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Strong motion records in China From: "Christos Papaioannou" chpapai@........ Date: Thu, 15 May 2008 20:53:06 +0300 Hello to everybody, Does anyone of you know anything about recorded accelerations after the big earthquake of May 14 in China? Is there any site IN ENGLISH where someone may find information on strong motion records in China? Thank you in advance Christos A. PAPAIOANNOU CONFIDENTIALITY AND DISCLAIMER NOTICE This e-mail is intended only for the addressee named above. It must not be read, copied, disclosed or used by any person other than the addressee(s) named above. If you received this e_mail in error, please return it to the sender. Any views or opinions presented are solely those of the sender and do not necessarily represent those of I.T.S.A.K. unless otherwise specifically stated. As Internet communications are not secure, I do not accept legal responsibility for the contents of this message nor responsibility for any change made to this message after the original sender sent it. I advise you to carry out your own virus check before opening any attachment, as I cannot accept liability for any damage sustained as a result of any software viruses. \\\|/// \\ - - // ( @ @ ) *-------oOOOo-(_)-oOOOo----------------------------------------------* * * * /\ * * / \ /\ /\ * * ___/\ / \ / \/\ / \/\/\_______ ITSAK * * \/ \ / \/ P.O. Box 53, Foinikas * * \/ GR-55102 Thessaloniki * * GREECE * * * * Christos A. PAPAIOANNOU tel. (+).30.2310476081 -84 * * Seismologist Ph.D. extension 127 * * fax (+).30.2310476085 * * cellular (+).30.6977217868 * * * * e_mail : chpapai@........ * *------------------Ooooo---------------------------------------------* ooooO ( ) ( ) ) / \ ( (_/ \_)
        Hello to=20 everybody,

        Does anyone = of you=20 know anything about recorded accelerations after the big
earthquake of = May 14 in=20 China?
        Is there any site IN = ENGLISH=20 where someone may find information on strong
motion = records in=20 China?
 
        Thank you in advance
         Christos  A. = PAPAIOANNOU


 CONFIDENTIALITY AND DISCLAIMER=20 NOTICE
 This  e-mail is intended only for the addressee = named=20 above.
 It must not be read, copied, disclosed or used by any = person=20 other
than  the=20 addressee(s) named above. If you received this e_mail  in
error, = please=20 return it to the sender.
 Any views or opinions presented are = solely=20 those of the sender and
do not necessarily represent those of =20 I.T.S.A.K. unless  otherwise
specifically stated.
 As = Internet=20 communications are not  secure,  I do not accept=20 legal
responsibility for the contents of  this message nor=20 responsibility
for any  change made to this message after the = original=20 sender sent
it.
 I advise you to carry out your own virus = check=20 before  opening any
attachment, as I cannot accept  = liability =20 for any damage sustained
as a result of any software=20 viruses.


         = ;  =20 \\\|///
          = \\  -=20 -  = //
          =20 (  @ @ =20 )
*-------oOOOo-(_)-oOOOo---------------------------------------------= -*
*           =             &= nbsp;           &n= bsp;           &nb= sp;           &nbs= p;       =20 *
*         =20 /\            = ;            =             &= nbsp;           &n= bsp;      =20 *
*         / =20 \      /\     =20 /\            = ;            =             &= nbsp; =20 *
* ___/\  /    \    /  = \/\ =20 /  \/\/\_______=20 ITSAK           &n= bsp;        =20 *
*      \/      = \ =20 /     =20 \/            = ;   =20 P.O. Box 53, Foinikas    =20 *
*           &= nbsp;  =20 \/            = ;            = =20 GR-55102 Thessaloniki    =20 *
*           &= nbsp;           &n= bsp;           &nb= sp;     =20 GREECE           &= nbsp;       =20 *
*           &= nbsp;           &n= bsp;           &nb= sp;           &nbs= p;            = ;       =20 *
*    Christos A.=20 PAPAIOANNOU          &n= bsp;  =20 tel. (+).30.2310476081 -84 *
*    Seismologist=20 Ph.D.           &n= bsp;           &nb= sp;  =20 extension 127     =20 *
*           &= nbsp;           &n= bsp;           &nb= sp;    =20 fax  (+).30.2310476085    =20 *
*           &= nbsp;           &n= bsp;           &nb= sp;    =20 cellular (+).30.6977217868=20 *
*           &= nbsp;           &n= bsp;           &nb= sp;           &nbs= p;            = ;       =20 *
*           &= nbsp;           &n= bsp;           &nb= sp;    =20 e_mail : chpapai@........ =20 *
*------------------Ooooo--------------------------------------------= -*
         =20 ooooO    (   =20 )
          = (   =20 )    ) =20 /
           = \ =20 (    =20 (_/
           = =20 \_)

Subject: Round external coils and stacked internal magnets From: "meredith lamb" paleoartifact@......... Date: Fri, 16 May 2008 11:47:57 -0600 Hi all, Am getting to the (shall we say a unqualified) opinion that with a choice of round or square/rectangular coils with a magnet, that it seems like the round coil approach is the more efficient route to take. It just simply uses all the coil and not just a couple selected sides mainly. Theres obviously no heavy problem to making a round coil; versus the more construction work with a square or rectangular coil. The route you take with the round coil size/shape with the magnet/s can be quite different than most now use. Having multi or multiple round (or ring) magnets stacked attracting, with the coil on the outside centered seems to be a sensitive and quick approach. One magnet can work, but with 2 or more, it will increase the sensitivity, and, the coil will be normally centered down the length of the magnet stack. The magnets are still mounted on a metal plate. It still works normally; i.e., movement in one direction will still be + or - throughout its continued movement in that direction; and vice versa + or - signal for the other direction. For home brew seismometers with a heavy mechanical boom/coil drift problem; this approach would seem to be the best ideal design answer. Although I've not actually done it, one could also put a iron can around and slightly away from such a coil/magnet assembly, and slightly increase the sensitivity, while also providing a measure of limiting some magnetic or electro magnetic induction "noise" pickup and air or thermal influence also. Tight and limited movement magnet coil assemblys are interesting to be sure; but what the heck; your amplifier gain controls should easily take up any slack. Take care, Meredith Lamb Hi all,

Am getting to the (shall we say a unqualified) opinion that with a choice of round or square/rectangular coils
with a magnet, that it seems like the round coil approach is the more efficient route to take.  It just simply
uses all the coil and not just a couple selected sides mainly.  Theres obviously no heavy
problem to making a round coil; versus the more construction work with a square or rectangular coil. 

The route you take with the round coil size/shape with the magnet/s can be quite different than most now use.

Having multi or multiple round (or ring) magnets stacked attracting, with the coil on the outside centered
seems to be a sensitive and quick approach.   One magnet can work, but with 2 or more, it will increase
the sensitivity, and, the coil will be normally centered down the length of the magnet stack.  The magnets
are still mounted on a metal plate.  It still works normally; i.e., movement in one direction will still be + or -
throughout its continued movement in that direction; and vice versa + or - signal for the other direction.

For home brew seismometers with a heavy mechanical boom/coil drift problem; this approach would seem
to be the best ideal design answer.

Although I've not actually done it, one could also put a iron can around and slightly away from
such a coil/magnet assembly, and slightly increase the sensitivity, while also providing a measure
of limiting some magnetic or electro magnetic induction "noise" pickup and air or thermal influence also.

Tight and limited movement magnet coil assemblys are interesting to be sure; but what the heck; your
amplifier gain controls should easily take up any slack.

Take care, Meredith Lamb

Subject: Re: Round external coils and stacked internal magnets From: ian ian@........... Date: Fri, 16 May 2008 19:25:11 +0100 Hi, I too have a heretical arrangement: Round coil mounted on the ground and a single column horizontal stack of 7 10mm cubed neodymium magnets attached to the end of the pendulum, perpendicular to it, which moves back and forth inside and along the internal axis of the coil. This non-optimum arrangement does simplify the mechanical design in that there are no signal wires coming off the pendulum. It would be interesting to hear how much is lost by this non-optimum arrangement. Is it worth the modification? Ian meredith lamb wrote: > Hi all, > > Am getting to the (shall we say a unqualified) opinion that with a > choice of round or square/rectangular coils > with a magnet, that it seems like the round coil approach is the more > efficient route to take. It just simply > uses all the coil and not just a couple selected sides mainly. Theres > obviously no heavy > problem to making a round coil; versus the more construction work with > a square or rectangular coil. > > The route you take with the round coil size/shape with the magnet/s > can be quite different than most now use. > > Having multi or multiple round (or ring) magnets stacked attracting, > with the coil on the outside centered > seems to be a sensitive and quick approach. One magnet can work, but > with 2 or more, it will increase > the sensitivity, and, the coil will be normally centered down the > length of the magnet stack. The magnets > are still mounted on a metal plate. It still works normally; i.e., > movement in one direction will still be + or - > throughout its continued movement in that direction; and vice versa + > or - signal for the other direction. > > For home brew seismometers with a heavy mechanical boom/coil drift > problem; this approach would seem > to be the best ideal design answer. > > Although I've not actually done it, one could also put a iron can > around and slightly away from > such a coil/magnet assembly, and slightly increase the sensitivity, > while also providing a measure > of limiting some magnetic or electro magnetic induction "noise" pickup > and air or thermal influence also. > > Tight and limited movement magnet coil assemblys are interesting to be > sure; but what the heck; your > amplifier gain controls should easily take up any slack. > > Take care, Meredith Lamb > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Round external coils and stacked internal magnets From: ChrisAtUpw@....... Date: Fri, 16 May 2008 16:56:48 EDT In a message dated 2008/05/16, paleoartifact@......... writes: > Am getting to the (shall we say a unqualified) opinion that with a choice > of round or square / rectangular coils with a magnet, that it seems like the > round coil approach is the more efficient route to take. Hi Meredith, If you want an accurately linear output from a Lehman, while allowing for the large sensor drifts that you always get, you definitely need to use a quad arrangement of square NdFeB magnets and a rectangular coil. Round coils will DEFINITELY NOT give you a constant sensitivity over the drift range of a Lehman sensor. If you are using a vertical pendulum, you can use a quad arrangement of rectangular magnets with the width of a magnet ~ the ID of the coil. Alternatively, you can make up a magnet block and attach it to the pendulum to form part or all of the mass. But you will then still get a small sensitivity to environmental magnetic fields. You make the ID of the actual windings about 3/4 of the width of a magnet and the internal length about 1/5 greater. This allows for some position error either as the coil swings in an arc or for any setup position error. The flux change for a given magnet movement is then CONSTANT over maybe 3/4" drift with 1" square magnets. Mount the magnets on 1/4" thick mild steel backing plates held apart with zinc plated mild steel bolts. You need to give the mild steel some etch primer and a coat of anti rust paint. I use Hermetite. You paint the whole surface of the plates, then leave them a couple of days for the paint to harden. I make up a cardboard cut-out, clamp it to the plate and slide the magnets into position over the cardboard. This is 'the easy way to do it'! One advantage of this construction is that you only need maybe 2,500 turns on you coil. The voltage output is maybe 10x what you get with a U Alnico magnet. This arrangement is shown on the drawings at http://www.jclahr.com/science/psn/chapman/lehman/index.html It is quite easy to make a rectangular coil former out of thin glass circuit board / sheet glass fibre. DigiKey sell both. You can either use the construction shown, or you can make a wood / plastic inner coil former and screw / glue it between two sheets to form the ends of the coil. I suggest winding it using a bolt through the centre gripped by a hand drill, held in a vice. Use some fine plastic tube to guide the wire onto the coil. Spray cans usually have suitable tube if you open one up. I use two part Acrylic glue - Devcon Plastic Welder or similar. I defiitely avoid using 'coil dope' - I find that I get too many shorted turns. You can use coil dope OK if you very carefully wind a single layer of wire at a time and then use tissue paper to interleave the winding layers. With luck, you are only going to ever make one coil per seismometer, so it REALL IS worth a bit of extra effort to get the best out of your instrument. Regards, Chris Chapman In a me= ssage dated 2008/05/16, paleoartifact@......... writes:

Am getting to the (shall we say= a unqualified) opinion that with a choice of round or square / rectangular=20= coils with a magnet, that it seems like the round coil approach is the more=20= efficient route to take.


Hi Meredith,

       If you want an accurately linear output= from a Lehman, while allowing for the large sensor drifts that you always g= et, you definitely need to use a quad arrangement of square NdFeB magnets an= d a rectangular coil.

       Round coils will DEFINITELY NOT give yo= u a constant sensitivity over the drift range of a Lehman sensor.
       If you are using a vertical pendulum, y= ou can use a quad arrangement of rectangular magnets with the width of a mag= net ~ the ID of the coil. Alternatively, you can make up a magnet block and=20= attach it to the pendulum to form part or all of the mass. But you will then= still get a small sensitivity to environmental magnetic fields.

       You make the ID of the actual windings=20= about 3/4 of the width of a magnet and the internal length about 1/5 greater= .. This allows for some position error either as the coil swings in an arc or= for any setup position error.  The flux change for a given magnet move= ment is then CONSTANT over maybe 3/4" drift with 1" square magnets.

       Mount the magnets on 1/4" thick mild st= eel backing plates held apart with zinc plated mild steel bolts. You need to= give the mild steel some etch primer and a coat of anti rust paint. I use H= ermetite. You paint the whole surface of the plates, then leave them a coupl= e of days for the paint to harden. I make up a cardboard cut-out, clamp it t= o the plate and slide the magnets into position over the cardboard. This is=20= 'the easy way to do it'!

       One advantage of this construction is t= hat you only need maybe 2,500 turns on you coil. The voltage output is maybe= 10x what you get with a U Alnico magnet.

       This arrangement is shown on the drawin= gs at http://www.jclahr.com/science/psn/chapman/lehman/index.html

       It is quite easy to make a rectangular=20= coil former out of thin glass circuit board / sheet glass fibre. DigiKey sel= l both. You can either use the construction shown, or you can make a wood /=20= plastic inner coil former and screw / glue it between two sheets to form the= ends of the coil. I suggest winding it using a bolt through the centre grip= ped by a hand drill, held in a vice. Use some fine plastic tube to guide the= wire onto the coil. Spray cans usually have suitable tube if you open one u= p. I use two part Acrylic glue - Devcon Plastic Welder or similar.

       I defiitely avoid using 'coil dope' - I= find that I get too many shorted turns. You can use coil dope OK if you ver= y carefully wind a single layer of wire at a time and then use tissue paper=20= to interleave the winding layers.

       With luck, you are only going to ever m= ake one coil per seismometer, so it REALL IS worth a bit of extra effort to=20= get the best out of your instrument.

       Regards,

       Chris Chapman Subject: Oil Furnace Nozzle Connection From: "Gary Lindgren" gel@................. Date: Fri, 16 May 2008 15:13:36 -0700 The typical Lehman uses an oil furnace nozzle as a connection point for the upper end of the music wire that is attached to the boom. What method is used to modify the nozzle in order to fasten the wire. What modifications are made. Thank you Gary Lindgren Gary Lindgren 585 Lincoln Ave Palo Alto CA 94301 650-326-0655 www.blue-eagle-technologies.com cymonsplace.blogspot.com

The typical Lehman uses an oil furnace nozzle as a connection point for the upper end of the music wire that is attached to = the boom. What method is used to modify the nozzle in order to fasten the = wire. What modifications are made.

Thank you

Gary Lindgren

 

 

 

 

Gary Lindgren

585 Lincoln Ave

Palo Alto CA 94301

 

650-326-0655<= /span>

 

www.blue-eagle-technologies.com

cymonsplace.blogspot.com 

 

Subject: Re: Oil Furnace Nozzle Connection From: ChrisAtUpw@....... Date: Fri, 16 May 2008 19:45:05 EDT In a message dated 2008/05/16, gel@................. writes: > The typical Lehman uses an oil furnace nozzle as a connection point for the > upper end of the music wire that is attached to the boom. What method is > used to modify the nozzle in order to fasten the wire. What modifications are > made. Hi Gary, The idea was to choose a music wire ~ the same diameter as the nozzle bore, but I don't know what that is. http://www.daddario.com/ list most of the music wires that are made. It is worthwhile getting wire which is nickel plated to minimise any rust problems. You might find it easier to clamp the wire between two washers? You do need to drill a hole for the wire through the centre of the clamp bolt. On system that I have used successfully is to mount the bottom SS ball bearing in the end of 3/8" bolt. I drill out a cone in the end of the bolt with a centre drill and stick the ball in place. Then I mount the bolt through the upright column with nuts and washers on both sides. This allows me to alter the horizontal position of the ball. I use a SS scalpel blade on the end of the arm as the hard counterface. The top suspension is another 3/8" bolt similarly fitted to the upright column. I file off about 3/8" of the threaded end of the bolt, about half way through and file just the thread off the other side of the bolt. I then drill a 1/8" hold in the centre of the flat and use an 1/8" bolt and two washers to clamp the music wire. SS bearings are stocked by www.smallparts.com. I stroingly advise against trying to use a knife edge or a point suspension. Ball on a plane and crossed cylinder suspensions both give much better results. These two adjustment bolts allow me to set up the seismometer so that it has a period of about 10 seconds when the baseplate is level. I then trim the period by raising the end of the base. Have a look at the school seismometers at http://www.jclahr.com/science/psn/chapman/school/MKII/index.html and at http://www.bgs.ac.uk/education/school_seismology/seismometer.html The first one used eccentric washers to set the position of the top suspension. Make the seismometer as one unit with a long base. This is far easier to set up and to adjust than the types described on psn. I have used 3" x 1" U channl Aluminum for the frame and cross piece, with 1/8" thick triangular corner plates at the main joint. I use SS bolts in contact with the Al. Regards, Chris Chapman In a me= ssage dated 2008/05/16, gel@................. writes:

The typical Lehman uses an oil=20= furnace nozzle as a connection point for the upper end of the music wire tha= t is attached to the boom. What method is used to modify the nozzle in order= to fasten the wire. What modifications are made.


Hi Gary,

       The idea was to choose a music wire ~ t= he same diameter as the nozzle bore, but I don't know what that is. http://w= ww.daddario.com/ list most of the music wires that are made. It is worthwhil= e getting wire which is nickel plated to minimise any rust problems.

       You might find it easier to clamp the w= ire between two washers? You do need to drill a hole for the wire through th= e centre of the clamp bolt.

       On system that I have used successfully= is to mount the bottom SS ball bearing in the end of 3/8" bolt. I drill out= a cone in the end of the bolt with a centre drill and stick the ball in pla= ce. Then I mount the bolt through the upright column with nuts and washers o= n both sides. This allows me to alter the horizontal position of the ball. I= use a SS scalpel blade on the end of the arm as the hard counterface.
       The top suspension is another 3/8" bolt= similarly fitted to the upright column. I file off about 3/8" of the thread= ed end of the bolt, about half way through and file just the thread off the=20= other side of the bolt. I then drill a 1/8" hold in the centre of the flat a= nd use an 1/8" bolt and two washers to clamp the music wire.
       SS bearings are stocked by www.smallpar= ts.com.
       I stroingly advise against trying to us= e a knife edge or a point suspension. Ball on a plane and crossed cylinder s= uspensions both give much better results.
       These two adjustment bolts allow me to=20= set up the seismometer so that it has a period of about 10 seconds when the=20= baseplate is level. I then trim the period by raising the end of the base.        Have a look at the school seismometers=20= at http://www.jclahr.com/science/psn/chapman/school/MKII/index.html and at <= BR> http://www.bgs.ac.uk/education/school_seismology/seismometer.html  = ; 
       The first one used eccentric washers to= set the position of the top suspension.
       Make the seismometer as one unit with a= long base. This is far easier to set up and to adjust than the types descri= bed on psn.
       I have used 3" x 1" U channl Aluminum f= or the frame and cross piece, with 1/8" thick triangular corner plates at th= e main joint. I use SS bolts in contact with the Al.

       Regards,

       Chris Chapman Subject: RE: Oil Furnace Nozzle Connection From: "Gary Lindgren" gel@................. Date: Fri, 16 May 2008 17:40:19 -0700 Chris, Thank you for the fine pictures. Yes, I throw out the idea of using the oil furnace nozzle. For the ball bearing I'm going to use a ceramic ball bearing. It is extremely hard and then I will use 2 crossed hardened dowel pins on the vertical post. Gary Lindgren From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of ChrisAtUpw@....... Sent: Friday, May 16, 2008 4:45 PM To: psn-l@.............. Subject: Re: Oil Furnace Nozzle Connection In a message dated 2008/05/16, gel@................. writes: The typical Lehman uses an oil furnace nozzle as a connection point for the upper end of the music wire that is attached to the boom. What method is used to modify the nozzle in order to fasten the wire. What modifications are made. Hi Gary, The idea was to choose a music wire ~ the same diameter as the nozzle bore, but I don't know what that is. http://www.daddario.com/ list most of the music wires that are made. It is worthwhile getting wire which is nickel plated to minimise any rust problems. You might find it easier to clamp the wire between two washers? You do need to drill a hole for the wire through the centre of the clamp bolt. On system that I have used successfully is to mount the bottom SS ball bearing in the end of 3/8" bolt. I drill out a cone in the end of the bolt with a centre drill and stick the ball in place. Then I mount the bolt through the upright column with nuts and washers on both sides. This allows me to alter the horizontal position of the ball. I use a SS scalpel blade on the end of the arm as the hard counterface. The top suspension is another 3/8" bolt similarly fitted to the upright column. I file off about 3/8" of the threaded end of the bolt, about half way through and file just the thread off the other side of the bolt. I then drill a 1/8" hold in the centre of the flat and use an 1/8" bolt and two washers to clamp the music wire. SS bearings are stocked by www.smallparts.com. I stroingly advise against trying to use a knife edge or a point suspension. Ball on a plane and crossed cylinder suspensions both give much better results. These two adjustment bolts allow me to set up the seismometer so that it has a period of about 10 seconds when the baseplate is level. I then trim the period by raising the end of the base. Have a look at the school seismometers at http://www.jclahr.com/science/psn/chapman/school/MKII/index.html and at http://www.bgs.ac.uk/education/school_seismology/seismometer.html The first one used eccentric washers to set the position of the top suspension. Make the seismometer as one unit with a long base. This is far easier to set up and to adjust than the types described on psn. I have used 3" x 1" U channl Aluminum for the frame and cross piece, with 1/8" thick triangular corner plates at the main joint. I use SS bolts in contact with the Al. Regards, Chris Chapman

Chris,

Thank you for the fine pictures. Yes, I throw out the = idea of using the oil furnace nozzle. For the ball bearing I’m going to = use a ceramic ball bearing. It is extremely hard and then I will use 2 crossed = hardened dowel pins on the vertical post.

Gary Lindgren

 

 

 

 

 

From:= = psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of = ChrisAtUpw@.......
Sent: Friday, May 16, 2008 4:45 PM
To: psn-l@..............
Subject: Re: Oil Furnace Nozzle Connection

 

In a message dated 2008/05/16, gel@................. writes:


The typical Lehman uses an oil furnace nozzle as a connection point for the = upper end of the music wire that is attached to the boom. What method is used = to modify the nozzle in order to fasten the wire. What modifications are = made.



Hi Gary,

       The idea was to choose a music wire = ~ the same diameter as the nozzle bore, but I don't know what that is. http://www.daddario.com/ list most of the music wires that are made. It = is worthwhile getting wire which is nickel plated to minimise any rust = problems.

       You might find it easier to clamp = the wire between two washers? You do need to drill a hole for the wire through = the centre of the clamp bolt.

       On system that I have used = successfully is to mount the bottom SS ball bearing in the end of 3/8" bolt. I = drill out a cone in the end of the bolt with a centre drill and stick the ball in = place. Then I mount the bolt through the upright column with nuts and washers = on both sides. This allows me to alter the horizontal position of the ball. I = use a SS scalpel blade on the end of the arm as the hard counterface.
       The top suspension is another = 3/8" bolt similarly fitted to the upright column. I file off about 3/8" = of the threaded end of the bolt, about half way through and file just the = thread off the other side of the bolt. I then drill a 1/8" hold in the centre = of the flat and use an 1/8" bolt and two washers to clamp the music wire. =
       SS bearings are stocked by www.smallparts.com.
       I stroingly advise against trying = to use a knife edge or a point suspension. Ball on a plane and crossed cylinder = suspensions both give much better results.
       These two adjustment bolts allow me = to set up the seismometer so that it has a period of about 10 seconds when the baseplate is level. I then trim the period by raising the end of the = base.
       Have a look at the school = seismometers at http://www.jclahr.com/science/psn/chapman/school/MKII/index.html and at =
http://www.bgs.ac.uk/education/school_seismology/seismometer.html &n= bsp; 
       The first one used eccentric = washers to set the position of the top suspension.
       Make the seismometer as one unit = with a long base. This is far easier to set up and to adjust than the types = described on psn.
       I have used 3" x 1" U = channl Aluminum for the frame and cross piece, with 1/8" thick triangular = corner plates at the main joint. I use SS bolts in contact with the Al.

       Regards,

       Chris Chapman

Subject: Re: Oil Furnace Nozzle Connection From: ChrisAtUpw@....... Date: Fri, 16 May 2008 22:55:48 EDT In a message dated 2008/05/17, gel@................. writes: > I will use 2 crossed hardened dowel pins on the vertical post. > Gary Lindgren Hi Gary, Unless they are carbide or stainless steel they won't last long. You get surface corrosion actively promoted between dry rolling surfaces. And I would advise against using oil. It doesn't last long and the bearings tend to slip out of position. You can get polished stainless type 415 shoulder bolts from McMaster Carr. http://www.mcmaster.com/ I think that John Cole uses these. Regards, Chris Chapman In a me= ssage dated 2008/05/17, gel@................. writes:

I will use 2 crossed hardened d= owel pins on the vertical post.
Gary Lindgren


Hi Gary,

       Unless they are carbide or stainless st= eel they won't last long. You get surface corrosion actively promoted betwee= n dry rolling surfaces. And I would advise against using oil. It doesn't las= t long and the bearings tend to slip out of position.

        You can get polished stainless ty= pe 415 shoulder bolts from McMaster Carr. http://www.mcmaster.com/ I think t= hat John Cole uses these.

       Regards,

       Chris Chapman
 Subject: Re: China Quake From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sat, 17 May 2008 04:18:45 +0000 Hi all Here are two articals on the China earthquake. http://news.nationalgeographic.com/news/2008/05/080516-earthquake-predicted= ..html http://news.nationalgeographic.com/news/2008/05/080515-AP-china-quake.html Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Round external coils and stacked internal magnets From: "meredith lamb" paleoartifact@......... Date: Fri, 16 May 2008 22:21:56 -0600 Hi Chris and all, Thanks Chris for the extensive reply below. Actually my impression with the stacked magnets came from trying to utilize a old surplus Texas Instruments rectangular coil form, and at the time, the stacked magnets approach seemed quite impressive at the time via a table top and voltmeter experiment. The problem with the coil is it has relatively thin walls, and I'am not so sure that a quad (4) magnet setup is the best or only approach. Its possible to use 3 magnets and essentially get a similar "quad" (4 pole) arrangement, where the fields go through the sides of the coil walls. The coil form shape is quite similar to transformer coil forms, and in a sense there maybe 2 ways to use magnets with them. Esterline-Angus also made similar coils back in the 1950's, of which I also have some of those. I put up a quick web page with 2 photos on the TI coil; along with my "notes/ramblings" related to such: http://seismometer.googlepages.com/tirectiwritercoilconversion Take care, Meredith Lamb On Fri, May 16, 2008 at 2:56 PM, wrote: > In a message dated 2008/05/16, paleoartifact@......... writes: > > Am getting to the (shall we say a unqualified) opinion that with a choice > of round or square / rectangular coils with a magnet, that it seems like the > round coil approach is the more efficient route to take. > > > > Hi Meredith, > > If you want an accurately linear output from a Lehman, while > allowing for the large sensor drifts that you always get, you definitely > need to use a quad arrangement of square NdFeB magnets and a rectangular > coil. > > Round coils will DEFINITELY NOT give you a constant sensitivity over > the drift range of a Lehman sensor. > If you are using a vertical pendulum, you can use a quad arrangement > of rectangular magnets with the width of a magnet ~ the ID of the coil. > Alternatively, you can make up a magnet block and attach it to the pendulum > to form part or all of the mass. But you will then still get a small > sensitivity to environmental magnetic fields. > > You make the ID of the actual windings about 3/4 of the width of a > magnet and the internal length about 1/5 greater. This allows for some > position error either as the coil swings in an arc or for any setup position > error. The flux change for a given magnet movement is then CONSTANT over > maybe 3/4" drift with 1" square magnets. > > Mount the magnets on 1/4" thick mild steel backing plates held apart > with zinc plated mild steel bolts. You need to give the mild steel some etch > primer and a coat of anti rust paint. I use Hermetite. You paint the whole > surface of the plates, then leave them a couple of days for the paint to > harden. I make up a cardboard cut-out, clamp it to the plate and slide the > magnets into position over the cardboard. This is 'the easy way to do it'! > > One advantage of this construction is that you only need maybe 2,500 > turns on you coil. The voltage output is maybe 10x what you get with a U > Alnico magnet. > > This arrangement is shown on the drawings at > http://www.jclahr.com/science/psn/chapman/lehman/index.html > > It is quite easy to make a rectangular coil former out of thin glass > circuit board / sheet glass fibre. DigiKey sell both. You can either use the > construction shown, or you can make a wood / plastic inner coil former and > screw / glue it between two sheets to form the ends of the coil. I suggest > winding it using a bolt through the centre gripped by a hand drill, held in > a vice. Use some fine plastic tube to guide the wire onto the coil. Spray > cans usually have suitable tube if you open one up. I use two part Acrylic > glue - Devcon Plastic Welder or similar. > > I defiitely avoid using 'coil dope' - I find that I get too many > shorted turns. You can use coil dope OK if you very carefully wind a single > layer of wire at a time and then use tissue paper to interleave the winding > layers. > > With luck, you are only going to ever make one coil per seismometer, > so it REALL IS worth a bit of extra effort to get the best out of your > instrument. > > Regards, > > Chris Chapman Hi Chris and all,

Thanks Chris for the extensive reply below.  Actually my impression with the stacked magnets came from
trying to utilize a old surplus Texas Instruments rectangular coil form, and at the time, the stacked
magnets approach seemed quite impressive at the time via a table top and voltmeter experiment.

The problem with the coil is it has relatively thin walls, and I'am not so sure that a quad (4) magnet
setup is the best or only approach.  Its possible to use 3 magnets and essentially get a similar "quad" (4 pole)
arrangement, where the fields go through the sides of the coil walls.

The coil form shape is quite similar to transformer coil forms, and in a sense there maybe 2 ways to
use magnets with them.  Esterline-Angus also made similar coils back in the 1950's, of which
I also have some of those.

I put up a quick web page with 2 photos on the TI coil; along with my "notes/ramblings" related to such:

http://seismometer.googlepages.com/tirectiwritercoilconversion

Take care, Meredith Lamb


On Fri, May 16, 2008 at 2:56 PM, <ChrisAtUpw@.......> wrote:
In a message dated 2008/05/16, paleoartifact@......... writes:

Am getting to the (shall we say a unqualified) opinion that with a choice of round or square / rectangular coils with a magnet, that it seems like the round coil approach is the more efficient route to take.


Hi Meredith,

       If you want an accurately linear output from a Lehman, while allowing for the large sensor drifts that you always get, you definitely need to use a quad arrangement of square NdFeB magnets and a rectangular coil.

       Round coils will DEFINITELY NOT give you a constant sensitivity over the drift range of a Lehman sensor.
       If you are using a vertical pendulum, you can use a quad arrangement of rectangular magnets with the width of a magnet ~ the ID of the coil. Alternatively, you can make up a magnet block and attach it to the pendulum to form part or all of the mass. But you will then still get a small sensitivity to environmental magnetic fields.

       You make the ID of the actual windings about 3/4 of the width of a magnet and the internal length about 1/5 greater. This allows for some position error either as the coil swings in an arc or for any setup position error.  The flux change for a given magnet movement is then CONSTANT over maybe 3/4" drift with 1" square magnets.

       Mount the magnets on 1/4" thick mild steel backing plates held apart with zinc plated mild steel bolts. You need to give the mild steel some etch primer and a coat of anti rust paint. I use Hermetite. You paint the whole surface of the plates, then leave them a couple of days for the paint to harden. I make up a cardboard cut-out, clamp it to the plate and slide the magnets into position over the cardboard. This is 'the easy way to do it'!

       One advantage of this construction is that you only need maybe 2,500 turns on you coil. The voltage output is maybe 10x what you get with a U Alnico magnet.

       This arrangement is shown on the drawings at http://www.jclahr.com/science/psn/chapman/lehman/index.html

       It is quite easy to make a rectangular coil former out of thin glass circuit board / sheet glass fibre. DigiKey sell both. You can either use the construction shown, or you can make a wood / plastic inner coil former and screw / glue it between two sheets to form the ends of the coil. I suggest winding it using a bolt through the centre gripped by a hand drill, held in a vice. Use some fine plastic tube to guide the wire onto the coil. Spray cans usually have suitable tube if you open one up. I use two part Acrylic glue - Devcon Plastic Welder or similar.

       I defiitely avoid using 'coil dope' - I find that I get too many shorted turns. You can use coil dope OK if you very carefully wind a single layer of wire at a time and then use tissue paper to interleave the winding layers.

       With luck, you are only going to ever make one coil per seismometer, so it REALL IS worth a bit of extra effort to get the best out of your instrument.

       Regards,

       Chris Chapman

Subject: RE: Round external coils and stacked internal magnets From: "Gary Lindgren" gel@................. Date: Fri, 16 May 2008 22:07:41 -0700 Meredith, I can't visualize the magnet layout you speak of with 3 magnets. Do you have a magnet placement diagram so that I could map out the magnetic fields. Gary Lindgren From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of meredith lamb Sent: Friday, May 16, 2008 9:22 PM To: psn-l@.............. Subject: Re: Round external coils and stacked internal magnets Hi Chris and all, Thanks Chris for the extensive reply below. Actually my impression with the stacked magnets came from trying to utilize a old surplus Texas Instruments rectangular coil form, and at the time, the stacked magnets approach seemed quite impressive at the time via a table top and voltmeter experiment. The problem with the coil is it has relatively thin walls, and I'am not so sure that a quad (4) magnet setup is the best or only approach. Its possible to use 3 magnets and essentially get a similar "quad" (4 pole) arrangement, where the fields go through the sides of the coil walls. The coil form shape is quite similar to transformer coil forms, and in a sense there maybe 2 ways to use magnets with them. Esterline-Angus also made similar coils back in the 1950's, of which I also have some of those. I put up a quick web page with 2 photos on the TI coil; along with my "notes/ramblings" related to such: http://seismometer.googlepages.com/tirectiwritercoilconversion Take care, Meredith Lamb On Fri, May 16, 2008 at 2:56 PM, wrote: In a message dated 2008/05/16, paleoartifact@......... writes: Am getting to the (shall we say a unqualified) opinion that with a choice of round or square / rectangular coils with a magnet, that it seems like the round coil approach is the more efficient route to take. Hi Meredith, If you want an accurately linear output from a Lehman, while allowing for the large sensor drifts that you always get, you definitely need to use a quad arrangement of square NdFeB magnets and a rectangular coil. Round coils will DEFINITELY NOT give you a constant sensitivity over the drift range of a Lehman sensor. If you are using a vertical pendulum, you can use a quad arrangement of rectangular magnets with the width of a magnet ~ the ID of the coil. Alternatively, you can make up a magnet block and attach it to the pendulum to form part or all of the mass. But you will then still get a small sensitivity to environmental magnetic fields. You make the ID of the actual windings about 3/4 of the width of a magnet and the internal length about 1/5 greater. This allows for some position error either as the coil swings in an arc or for any setup position error. The flux change for a given magnet movement is then CONSTANT over maybe 3/4" drift with 1" square magnets. Mount the magnets on 1/4" thick mild steel backing plates held apart with zinc plated mild steel bolts. You need to give the mild steel some etch primer and a coat of anti rust paint. I use Hermetite. You paint the whole surface of the plates, then leave them a couple of days for the paint to harden. I make up a cardboard cut-out, clamp it to the plate and slide the magnets into position over the cardboard. This is 'the easy way to do it'! One advantage of this construction is that you only need maybe 2,500 turns on you coil. The voltage output is maybe 10x what you get with a U Alnico magnet. This arrangement is shown on the drawings at http://www.jclahr.com/science/psn/chapman/lehman/index.html It is quite easy to make a rectangular coil former out of thin glass circuit board / sheet glass fibre. DigiKey sell both. You can either use the construction shown, or you can make a wood / plastic inner coil former and screw / glue it between two sheets to form the ends of the coil. I suggest winding it using a bolt through the centre gripped by a hand drill, held in a vice. Use some fine plastic tube to guide the wire onto the coil. Spray cans usually have suitable tube if you open one up. I use two part Acrylic glue - Devcon Plastic Welder or similar. I defiitely avoid using 'coil dope' - I find that I get too many shorted turns. You can use coil dope OK if you very carefully wind a single layer of wire at a time and then use tissue paper to interleave the winding layers. With luck, you are only going to ever make one coil per seismometer, so it REALL IS worth a bit of extra effort to get the best out of your instrument. Regards, Chris Chapman

Meredith,

I can’t visualize the magnet layout you speak of = with 3 magnets. Do you have a magnet placement diagram so that I could map out the = magnetic fields.

Gary Lindgren

 

 

 

 

From:= psn-l-request@.............. [mailto:psn-l-request@............... On = Behalf Of meredith lamb
Sent: Friday, May 16, 2008 9:22 PM
To: psn-l@..............
Subject: Re: Round external coils and stacked internal = magnets

 

Hi Chris and = all,

Thanks Chris for the extensive reply below.  Actually my impression = with the stacked magnets came from
trying to utilize a old surplus Texas Instruments rectangular coil form, = and at the time, the stacked
magnets approach seemed quite impressive at the time via a table top and voltmeter experiment.

The problem with the coil is it has relatively thin walls, and I'am not = so sure that a quad (4) magnet
setup is the best or only approach.  Its possible to use 3 magnets = and essentially get a similar "quad" (4 pole)
arrangement, where the fields go through the sides of the coil = walls.

The coil form shape is quite similar to transformer coil forms, and in a = sense there maybe 2 ways to
use magnets with them.  Esterline-Angus also made similar coils = back in the 1950's, of which
I also have some of those.

I put up a quick web page with 2 photos on the TI coil; along with my "notes/ramblings" related to such:

h= ttp://seismometer.googlepages.com/tirectiwritercoilconversion

Take care, Meredith Lamb

On Fri, May 16, 2008 at 2:56 PM, <ChrisAtUpw@.......> = wrote:

In a message dated 2008/05/16, paleoartifact@......... writes:


Am getting to the (shall we say a unqualified) opinion that with a choice = of round or square / rectangular coils with a magnet, that it seems like the = round coil approach is the more efficient route to take.

 

Hi Meredith,

       If you want an accurately linear = output from a Lehman, while allowing for the large sensor drifts that you = always get, you definitely need to use a quad arrangement of square NdFeB magnets = and a rectangular coil.

       Round coils will DEFINITELY NOT = give you a constant sensitivity over the drift range of a Lehman sensor.
       If you are using a vertical = pendulum, you can use a quad arrangement of rectangular magnets with the width of a = magnet ~ the ID of the coil. Alternatively, you can make up a magnet block and = attach it to the pendulum to form part or all of the mass. But you will then still = get a small sensitivity to environmental magnetic fields.

       You make the ID of the actual = windings about 3/4 of the width of a magnet and the internal length about 1/5 = greater. This allows for some position error either as the coil swings in an arc = or for any setup position error.  The flux change for a given magnet = movement is then CONSTANT over maybe 3/4" drift with 1" square = magnets.

       Mount the magnets on 1/4" = thick mild steel backing plates held apart with zinc plated mild steel bolts. You = need to give the mild steel some etch primer and a coat of anti rust paint. I = use Hermetite. You paint the whole surface of the plates, then leave them a = couple of days for the paint to harden. I make up a cardboard cut-out, clamp it = to the plate and slide the magnets into position over the cardboard. This is = 'the easy way to do it'!

       One advantage of this construction = is that you only need maybe 2,500 turns on you coil. The voltage output is maybe = 10x what you get with a U Alnico magnet.

       This arrangement is shown on the = drawings at http://www.jclahr.com/science/psn/chapman/lehman/index.= html

       It is quite easy to make a = rectangular coil former out of thin glass circuit board / sheet glass fibre. DigiKey = sell both. You can either use the construction shown, or you can make a wood = / plastic inner coil former and screw / glue it between two sheets to form = the ends of the coil. I suggest winding it using a bolt through the centre = gripped by a hand drill, held in a vice. Use some fine plastic tube to guide the = wire onto the coil. Spray cans usually have suitable tube if you open one up. = I use two part Acrylic glue - Devcon Plastic Welder or similar.

       I defiitely avoid using 'coil dope' = - I find that I get too many shorted turns. You can use coil dope OK if you = very carefully wind a single layer of wire at a time and then use tissue = paper to interleave the winding layers.

       With luck, you are only going to = ever make one coil per seismometer, so it REALL IS worth a bit of extra effort to = get the best out of your instrument.

       Regards,

       Chris Chapman

 

Subject: Re: Round external coils and stacked internal magnets From: "meredith lamb" paleoartifact@......... Date: Sat, 17 May 2008 00:52:04 -0600 Hi Gary, Imagine (or use) a rectangular piece of paper as the flat "steel plate". On it, place/lay 3 pencils spaced apart @ say 2 inches. The pencils are the imaginary rectangular "magnets" stuck to the " steel plate". The magnets are polarized through their thickness; and hence are arranged with say, the left magnet with the N pole up, then the center "magnet" has the S pole up, and the right pencil has the N pole up. The imaginary coil goes over the the center "magnet" (up-down motion) and in between the outer "magnets". This type of magnet is often called a motor or wind generator magnet, as the poles are through the thickness and not at the ends. Every magnet has two poles. Hence their is two attracting fields in between the left "magnet" and the center "magnet". The same goes with the same center "magnet" and the right "magnet"; hence you have 4 attracting fields acting on the single coil. The fields are of course, relatively straight across to the adjacent attracting magnet. The intensity of the fields depends on the magnets ratings, how close they are together, and it also depends on the coil itself. For example; If you only have one magnet you "could" get for example, say 3v max velocity. With two, it could jump to ~ 8v; but with 3 it probably goes over 15v max velocity. Of course it all depends on the coil used and the magnet rating and the magnet spacing. Take care, Meredith On Fri, May 16, 2008 at 11:07 PM, Gary Lindgren wrote: > Meredith, > > I can't visualize the magnet layout you speak of with 3 magnets. Do you > have a magnet placement diagram so that I could map out the magnetic fields. > > Gary Lindgren > > > > > > > > > > *From:* psn-l-request@.............. [mailto:psn-l-request@............... > *On Behalf Of *meredith lamb > *Sent:* Friday, May 16, 2008 9:22 PM > *To:* psn-l@.............. > *Subject:* Re: Round external coils and stacked internal magnets > > > > Hi Chris and all, > > Thanks Chris for the extensive reply below. Actually my impression with > the stacked magnets came from > trying to utilize a old surplus Texas Instruments rectangular coil form, > and at the time, the stacked > magnets approach seemed quite impressive at the time via a table top and > voltmeter experiment. > > The problem with the coil is it has relatively thin walls, and I'am not so > sure that a quad (4) magnet > setup is the best or only approach. Its possible to use 3 magnets and > essentially get a similar "quad" (4 pole) > arrangement, where the fields go through the sides of the coil walls. > > The coil form shape is quite similar to transformer coil forms, and in a > sense there maybe 2 ways to > use magnets with them. Esterline-Angus also made similar coils back in the > 1950's, of which > I also have some of those. > > I put up a quick web page with 2 photos on the TI coil; along with my > "notes/ramblings" related to such: > > http://seismometer.googlepages.com/tirectiwritercoilconversion > > Take care, Meredith Lamb > > On Fri, May 16, 2008 at 2:56 PM, wrote: > > In a message dated 2008/05/16, paleoartifact@......... writes: > > > Am getting to the (shall we say a unqualified) opinion that with a choice > of round or square / rectangular coils with a magnet, that it seems like the > round coil approach is the more efficient route to take. > > > > Hi Meredith, > > If you want an accurately linear output from a Lehman, while > allowing for the large sensor drifts that you always get, you definitely > need to use a quad arrangement of square NdFeB magnets and a rectangular > coil. > > Round coils will DEFINITELY NOT give you a constant sensitivity over > the drift range of a Lehman sensor. > If you are using a vertical pendulum, you can use a quad arrangement > of rectangular magnets with the width of a magnet ~ the ID of the coil. > Alternatively, you can make up a magnet block and attach it to the pendulum > to form part or all of the mass. But you will then still get a small > sensitivity to environmental magnetic fields. > > You make the ID of the actual windings about 3/4 of the width of a > magnet and the internal length about 1/5 greater. This allows for some > position error either as the coil swings in an arc or for any setup position > error. The flux change for a given magnet movement is then CONSTANT over > maybe 3/4" drift with 1" square magnets. > > Mount the magnets on 1/4" thick mild steel backing plates held apart > with zinc plated mild steel bolts. You need to give the mild steel some etch > primer and a coat of anti rust paint. I use Hermetite. You paint the whole > surface of the plates, then leave them a couple of days for the paint to > harden. I make up a cardboard cut-out, clamp it to the plate and slide the > magnets into position over the cardboard. This is 'the easy way to do it'! > > One advantage of this construction is that you only need maybe 2,500 > turns on you coil. The voltage output is maybe 10x what you get with a U > Alnico magnet. > > This arrangement is shown on the drawings at > http://www.jclahr.com/science/psn/chapman/lehman/index.html > > It is quite easy to make a rectangular coil former out of thin glass > circuit board / sheet glass fibre. DigiKey sell both. You can either use the > construction shown, or you can make a wood / plastic inner coil former and > screw / glue it between two sheets to form the ends of the coil. I suggest > winding it using a bolt through the centre gripped by a hand drill, held in > a vice. Use some fine plastic tube to guide the wire onto the coil. Spray > cans usually have suitable tube if you open one up. I use two part Acrylic > glue - Devcon Plastic Welder or similar. > > I defiitely avoid using 'coil dope' - I find that I get too many > shorted turns. You can use coil dope OK if you very carefully wind a single > layer of wire at a time and then use tissue paper to interleave the winding > layers. > > With luck, you are only going to ever make one coil per seismometer, > so it REALL IS worth a bit of extra effort to get the best out of your > instrument. > > Regards, > > Chris Chapman > > > Hi Gary,

Imagine (or use) a rectangular piece of paper as the flat "steel plate".  On it, place/lay 3 pencils spaced apart
@ say 2 inches.  The pencils are the imaginary rectangular "magnets" stuck to the " steel plate".  The magnets are polarized through their thickness; and hence are arranged with say, the left magnet with the N pole up, then
the center "magnet" has the S pole up, and the right pencil has the N pole up.  The imaginary coil goes
over the the center "magnet" (up-down motion) and in between the outer "magnets".  This type of magnet is
often called a motor or wind generator magnet, as the poles are through the thickness and not at the ends.

Every magnet has two poles.  Hence their is two attracting fields in between the left "magnet" and the
center "magnet".  The same goes with the same center "magnet" and the right "magnet"; hence you have
4 attracting fields acting on the single coil.  The fields are of course, relatively straight across to the adjacent
attracting magnet.

The intensity of the fields depends on the magnets ratings, how close they are together, and it also
depends on the coil itself. 

For example; If you only have one magnet you "could" get for example, say 3v max velocity.  With two, it
could jump to ~ 8v;  but with 3 it probably goes over 15v max velocity.  Of course it all depends on the coil
used and the magnet rating and the magnet spacing.

Take care, Meredith

On Fri, May 16, 2008 at 11:07 PM, Gary Lindgren <gel@.................> wrote:

Meredith,

I can't visualize the magnet layout you speak of with 3 magnets. Do you have a magnet placement diagram so that I could map out the magnetic fields.

Gary Lindgren

 

 

 

 

From: psn-l-request@.............. [mailto:psn-l-request@..............] On Behalf Of meredith lamb
Sent: Friday, May 16, 2008 9:22 PM
To: psn-l@..............
Subject: Re: Round external coils and stacked internal magnets

 

Hi Chris and all,

Thanks Chris for the extensive reply below.  Actually my impression with the stacked magnets came from
trying to utilize a old surplus Texas Instruments rectangular coil form, and at the time, the stacked
magnets approach seemed quite impressive at the time via a table top and voltmeter experiment.

The problem with the coil is it has relatively thin walls, and I'am not so sure that a quad (4) magnet
setup is the best or only approach.  Its possible to use 3 magnets and essentially get a similar "quad" (4 pole)
arrangement, where the fields go through the sides of the coil walls.

The coil form shape is quite similar to transformer coil forms, and in a sense there maybe 2 ways to
use magnets with them.  Esterline-Angus also made similar coils back in the 1950's, of which
I also have some of those.

I put up a quick web page with 2 photos on the TI coil; along with my "notes/ramblings" related to such:

http://seismometer.googlepages.com/tirectiwritercoilconversion

Take care, Meredith Lamb

On Fri, May 16, 2008 at 2:56 PM, <ChrisAtUpw@.......> wrote:

In a message dated 2008/05/16, paleoartifact@......... writes:


Am getting to the (shall we say a unqualified) opinion that with a choice of round or square / rectangular coils with a magnet, that it seems like the round coil approach is the more efficient route to take.

 

Hi Meredith,

       If you want an accurately linear output from a Lehman, while allowing for the large sensor drifts that you always get, you definitely need to use a quad arrangement of square NdFeB magnets and a rectangular coil.

       Round coils will DEFINITELY NOT give you a constant sensitivity over the drift range of a Lehman sensor.
       If you are using a vertical pendulum, you can use a quad arrangement of rectangular magnets with the width of a magnet ~ the ID of the coil. Alternatively, you can make up a magnet block and attach it to the pendulum to form part or all of the mass. But you will then still get a small sensitivity to environmental magnetic fields.

       You make the ID of the actual windings about 3/4 of the width of a magnet and the internal length about 1/5 greater. This allows for some position error either as the coil swings in an arc or for any setup position error.  The flux change for a given magnet movement is then CONSTANT over maybe 3/4" drift with 1" square magnets.

       Mount the magnets on 1/4" thick mild steel backing plates held apart with zinc plated mild steel bolts. You need to give the mild steel some etch primer and a coat of anti rust paint. I use Hermetite. You paint the whole surface of the plates, then leave them a couple of days for the paint to harden. I make up a cardboard cut-out, clamp it to the plate and slide the magnets into position over the cardboard. This is 'the easy way to do it'!

       One advantage of this construction is that you only need maybe 2,500 turns on you coil. The voltage output is maybe 10x what you get with a U Alnico magnet.

       This arrangement is shown on the drawings at http://www.jclahr.com/science/psn/chapman/lehman/index.html

       It is quite easy to make a rectangular coil former out of thin glass circuit board / sheet glass fibre. DigiKey sell both. You can either use the construction shown, or you can make a wood / plastic inner coil former and screw / glue it between two sheets to form the ends of the coil. I suggest winding it using a bolt through the centre gripped by a hand drill, held in a vice. Use some fine plastic tube to guide the wire onto the coil. Spray cans usually have suitable tube if you open one up. I use two part Acrylic glue - Devcon Plastic Welder or similar.

       I defiitely avoid using 'coil dope' - I find that I get too many shorted turns. You can use coil dope OK if you very carefully wind a single layer of wire at a time and then use tissue paper to interleave the winding layers.

       With luck, you are only going to ever make one coil per seismometer, so it REALL IS worth a bit of extra effort to get the best out of your instrument.

       Regards,

       Chris Chapman

 


Subject: Re: Oil Furnace Nozzle Connection From: "Connie & Jim Lehman" lehmancj@........... Date: Sat, 17 May 2008 06:58:09 -0400 Gary--the use of an oil furnace nozzle was adopted in the original = design as it it made a clean "hinge" for the wire support. We got the = idea from a support for a 6 ft. Foucault Pendulum demo that worked well. = The nozzle used had a half inch screw area. We drilled a half inch = hole is the upper crosspiece at an angle the wire support wire would = be--making a snug fit, Then epoxy the nozzle in place. Whatever wire = is chosen must support the mass without fatigue, and must pass through = the nozzle---enlarge the opening as necessary--but make it snug. Drill = a small hole on the back side of the upper crosspiece, bring the wire = out and anchor. If everything is pretty well in line, there is little = stress on the nozzle--and it can do its thing! There are other designs for the hinges-upper & lower-- that work = well--Whatever you choose you want stability with a good structural = support and minimal fatigue over time. Best wishes, Jim Lehman ----- Original Message -----=20 From: Gary Lindgren=20 To: PSN List=20 Sent: Friday, May 16, 2008 6:13 PM Subject: Oil Furnace Nozzle Connection The typical Lehman uses an oil furnace nozzle as a connection point = for the upper end of the music wire that is attached to the boom. What = method is used to modify the nozzle in order to fasten the wire. What = modifications are made. Thank you Gary Lindgren =20 =20 =20 =20 Gary Lindgren 585 Lincoln Ave Palo Alto CA 94301 =20 650-326-0655 =20 www.blue-eagle-technologies.com cymonsplace.blogspot.com=20 =20
Gary--the use of an oil furnace nozzle = was adopted=20 in the original design as it it made a clean "hinge" for the wire = support. =20 We got the idea from a support for a 6 ft. Foucault Pendulum demo = that=20 worked well.  The nozzle used had a half inch screw area.  We = drilled=20 a half inch hole is the upper crosspiece at an angle the wire support = wire would=20 be--making a snug fit,  Then epoxy the nozzle in place.  = Whatever wire=20 is chosen must support the mass without fatigue, and must pass through = the=20 nozzle---enlarge the opening as necessary--but make it snug.  Drill = a=20 small hole on the back side of the upper crosspiece, bring the wire = out and=20 anchor.  If everything is pretty well in line, there is little = stress on=20 the nozzle--and it can do its thing!
  There are other designs for the = hinges-upper=20 & lower-- that work well--Whatever you choose   you = want=20 stability with a good structural support and minimal fatigue = over=20 time.
 
Best wishes,  Jim = Lehman
----- Original Message -----
From:=20 Gary=20 Lindgren
Sent: Friday, May 16, 2008 6:13 = PM
Subject: Oil Furnace Nozzle=20 Connection

The typical Lehman uses an oil furnace nozzle as = a=20 connection point for the upper end of the music wire that is attached = to the=20 boom. What method is used to modify the nozzle in order to fasten the = wire.=20 What modifications are made.

Thank you

Gary Lindgren

 

 

 

 

Gary=20 Lindgren

585 = Lincoln=20 Ave

Palo Alto = CA=20 94301

 

650-326-0655

 

www.blue-eagle-technologies.com

cymonsplace.blogspot.com 

 

Subject: Re: China Quake<< wrote: Hi all Here are two articals on the China earthquake. http://news.nationalgeographic.com/news/2008/05/080516-earthquake-predic= ted.html http://news.nationalgeographic.com/news/2008/05/080515-AP-china-quake.ht= ml Regards. -- = J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) See http://www.seismicnet.com/maillist.html for more information. _____________________________________________________________ Don't stay in a roach motel. Click here to find great deals on hotels. http://thirdpartyoffers.juno.com/TGL2121/fc/Ioyw6i3nLmKrCkIgePSCUZTrK1v8= qDsxTLMdB1fZCtCFsLDwBFDN2y/?count=3D1234567890 Thanks Jon- The 2 articles are Outstanding.....Jim 

--= J=F3n Fr=EDmann <jonfr@.........> wrote:
Hi all

Here ar= e two articals on the China earthquake.

http://news.nationalgeogr= aphic.com/news/2008/05/080516-earthquake-predicted.html
http://news.n= ationalgeographic.com/news/2008/05/080515-AP-china-quake.html

Reg= ards.
--
J=F3n Fr=EDmann
http://www.jonfr.com
http://earthq= uakes.jonfr.com
http://www.net303.net
http://www.mobile-coverage.c= om/

__________________________________________________________
Public Seismic Network Mailing List (PSN-L)

To leave this li= st email PSN-L-REQUEST@.............. with
the body of the message (= first line only): unsubscribe
See http://www.seismicnet.com/maillist.= html for more information.

__________________________= ___________________________________
Don't stay in a roach motel. = Click here to find great deals on hotels.
 Subject: Re: China Quake From: "Dale Hardy" photon1@........... Date: Wed, 21 May 2008 23:45:24 +1000 Some dramatic images of the changed landscape after the event,.... watch for word wrap Dale http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=18034 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Expecting a big earthquake From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Thu, 22 May 2008 19:45:49 +0000 Hi all There is an earthquake swarm happening about 93 km south of my location (see here, http://hraun.vedur.is/ja/englishweb/index.html ). This swarm did start on Monday with few small earthquakes, but this morning it did release a M3.5 earthquake and many other smaller onces. Given the earthquake swarm pattern I am expecting a earthquake there that is ML4.0 up to ML5.5, but I doubt it is going to get bigger then mag 5.5. I expect this earthquake to happen in next two days at least, but this might take longer time to happen. That area last had a earthquake swarm in 1999, then it did start with a ML4.0 earthquake. Also in general earthquake news from Iceland it appears that number of earthquakes are on the rise, there appears to be high tension in the crust in Iceland. Earthquake recording might get intresting at any time for me. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Adjusting the period From: tchannel1@............ Date: Mon, 26 May 2008 08:29:07 -0600 Hi Folks, I have a Lehman set to 20 seconds..........It seems to be = working okay and I don't think it needs any modifications. It records = the same as other Lehmans I have worked with. I plan on changing the period from 20 seconds to another number, not = sure what that number will be. What I want to see, is how it records = at different period settings. I know the advantages of the 20 seconds. The disadvantage is it misses = many other smaller earthquakes. My question: Before I try other period numbers..........Have you tried = this, and what were the results? I really don't know what the result would be. Thanks, Ted
Hi  Folks,  I have a Lehman = set to 20=20 seconds..........It seems to be working okay and I don't think it needs = any=20 modifications.  It records the same as other Lehmans I have worked=20 with.
 
I plan on changing the period from 20 = seconds to=20 another number, not sure what that number will be.   What I = want to=20 see, is how it records at different period settings.
 
I know the advantages of the 20 = seconds.  The=20 disadvantage is it misses many other smaller earthquakes.
 
My question:  Before I try other = period=20 numbers..........Have you tried this, and what were the = results?
 
I really don't know what the result = would=20 be.
 
Thanks, Ted
Subject: Large earthquake triggers small onces at large distance From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 26 May 2008 18:23:54 +0000 Hi all It appears that large earthquakes, specally those how are bigger then Mw7.0 can trigger smaller earthquakes at great disance. Two articals about this below. http://www.sciencedaily.com/releases/2008/05/080525132352.htm http://www.msnbc.msn.com/id/24820044/ Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Adjusting the period From: ChrisAtUpw@....... Date: Mon, 26 May 2008 14:51:02 EDT In a message dated 2008/05/26, tchannel1@............ writes: > I plan on changing the period from 20 seconds to another number, not sure > what that number will be. What I want to see, is how it records at different > period settings. > I know the advantages of the 20 seconds. The disadvantage is it misses many > other smaller earthquakes. > My question: Before I try other period numbers..........Have you tried > this, and what were the results? > I really don't know what the result would be. Hi Ted, If your Lehman is working properly, it should see all signals between the natural resonant period, at say 20 seconds and the low pass fiolter of your amplifier at 10 Hz. If you set the period to 10 seconds, it will only record signals between 10 seconds and 10 Hz. It will have about 1/4 theprevious sensitivity to 20 second Love waves. You WILL NOT see any more Earthquakes this way. Remember that Lehmans are directional? Could this be why you are missing some quakes? What quakes have you missed and why do you think you should have recorded them? An alternative is that your suspension may be sticking and preventing the arm from moving freely. You may then only see larger quakes. Can you remind me what suspensions, top and bottom, you are using, please? Do you see the normal 4 to 8 second microseisms OK? Regards, Chris Chapman In a me= ssage dated 2008/05/26, tchannel1@............ writes:

I plan on changing the period f= rom 20 seconds to another number, not sure what that number will be. &n= bsp; What I want to see, is how it records at different period settings. I know the advantages of the 20 seconds.  The disadvantage is it misse= s many other smaller earthquakes.
My question:  Before I try other period numbers..........Have you trie= d this, and what were the results?
I really don't know what the result would be.


Hi Ted,

       If your Lehman is working properly, it=20= should see all signals between the natural resonant period, at say 20 second= s and the low pass fiolter of your amplifier at 10 Hz.

       If you set the period to 10 seconds, it= will only record signals between 10 seconds and 10 Hz. It will have about 1= /4 theprevious sensitivity to 20 second Love waves.

       You WILL NOT see any more Earthquakes t= his way.

       Remember that Lehmans are directional?=20= Could this be why you are missing some quakes? What quakes have you missed a= nd why do you think you should have recorded them?
       An alternative is that your suspension=20= may be sticking and preventing the arm from moving freely. You may then only= see larger quakes.
       Can you remind me what suspensions, top= and bottom, you are using, please?
       Do you see the normal 4 to 8 second mic= roseisms OK?

       Regards,

       Chris Chapman Subject: Re: Adjusting the period From: "Geoff" gmvoeth@........... Date: Mon, 26 May 2008 12:58:23 -0700 The Smaller The Bandwidth the lower the noise. Id recommend you try 4 seconds to your highest non-alising freq. But your electronics needs to match your hardware and I do not know unless you build your own how to deal with that. ----- Original Message ----- From: To: "psn" Sent: Monday, May 26, 2008 7:29 AM Subject: Adjusting the period Hi Folks, I have a Lehman set to 20 seconds..........It seems to be working okay and I don't think it needs any modifications. It records the same as other Lehmans I have worked with. I plan on changing the period from 20 seconds to another number, not sure what that number will be. What I want to see, is how it records at different period settings. I know the advantages of the 20 seconds. The disadvantage is it misses many other smaller earthquakes. My question: Before I try other period numbers..........Have you tried this, and what were the results? I really don't know what the result would be. Thanks, Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Adjusting the period From: ChrisAtUpw@....... Date: Mon, 26 May 2008 16:55:07 EDT In a message dated 2008/05/26, gmvoeth@........... writes: > The Smaller The Bandwidth the lower the noise. I'd recommend you try 4 > seconds to your highest non-alising freq. But your electronics needs to match > your > hardware and I do not know unless you build your own how to deal with that. Hi Geoff, Sure, but with Lehmans in Amateur situations you are usually limited by environmental noise, NOT by electronic noise. Regards, Chris Chapman In a me= ssage dated 2008/05/26, gmvoeth@........... writes:

The Smaller The Bandwidth the l= ower the noise. I'd recommend you try 4 seconds to your highest non-alising=20= freq. But your electronics needs to match your
hardware and I do not know unless you build your own how to deal with that.<= /BLOCKQUOTE>

Hi Geoff,

       Sure, but with Lehmans in Amateur situa= tions you are usually limited by environmental noise, NOT by electronic nois= e.

       Regards,

       Chris Chapman Subject: Re: Adjusting the period From: tchannel1@............ Date: Mon, 26 May 2008 17:39:01 -0600 Hi Chris, I did double check everything, and the sensor seems to be = working just fine. The reason I know it is missing earthquakes is that I am running three = channels, One vertical spring, one tiltmeter, and one = Lehman..........The Lehman misses a lot of events the other two record. Yes I think part of it is directional. Would you think this could account for it..............The Lehman is set = for twenty seconds, but at twenty seconds, I think it is maxed out, that = is to say, I don't think I could get 21 seconds. Even 20 seconds, for this unit, may be too much. I say that because it = drifts, sometimes falling 1/2" per week to the left or to the right. I = adjust it back to center and it stays only for a few days. Might it simply be this unit is not capable of working at 20 seconds. = The sticking you mentioned.........could this be because it is = overextended, perhaps this machine is only capable of a WORKING PERIOD = of 15 seconds???? When I set it to 20, and move the boom, it does go to center, but = because of the drift issue, it may not be capable of HOLDING CENTER. and = perhaps this is stopping its sensitivity to all but the larger = earthquakes???? On the good side the events it does record, 6.2 Alaska and 7.8 China, = look really good. Thanks for your help. Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Monday, May 26, 2008 12:51 PM Subject: Re: Adjusting the period In a message dated 2008/05/26, tchannel1@............ writes: I plan on changing the period from 20 seconds to another number, not = sure what that number will be. What I want to see, is how it records = at different period settings. I know the advantages of the 20 seconds. The disadvantage is it = misses many other smaller earthquakes. My question: Before I try other period numbers..........Have you = tried this, and what were the results? I really don't know what the result would be. Hi Ted, If your Lehman is working properly, it should see all signals = between the natural resonant period, at say 20 seconds and the low pass = fiolter of your amplifier at 10 Hz. If you set the period to 10 seconds, it will only record = signals between 10 seconds and 10 Hz. It will have about 1/4 theprevious = sensitivity to 20 second Love waves.=20 You WILL NOT see any more Earthquakes this way. Remember that Lehmans are directional? Could this be why you = are missing some quakes? What quakes have you missed and why do you = think you should have recorded them? An alternative is that your suspension may be sticking and = preventing the arm from moving freely. You may then only see larger = quakes. Can you remind me what suspensions, top and bottom, you are = using, please? Do you see the normal 4 to 8 second microseisms OK? Regards, Chris Chapman
Hi Chris,  I did double check = everything, and=20 the sensor seems to be working just fine.
 
The reason I know it is missing = earthquakes is that=20 I am running three channels, One vertical spring, one tiltmeter, and one = Lehman..........The Lehman misses a lot of events the other two=20 record.
 
Yes I think part of it is = directional.
 
Would you think this could account for=20 it..............The Lehman is set for twenty seconds, but at twenty = seconds, I=20 think it is maxed out, that is to say,  I don't think I could get = 21=20 seconds.
Even 20 seconds, for this unit, may be = too=20 much.   I say that because it drifts, sometimes falling 1/2" = per week=20 to the left or to the right.  I adjust it back to  center and = it stays=20 only for a few days.
 
Might it simply be this unit is not = capable of=20 working at 20 seconds.   The sticking you = mentioned.........could this=20 be because it is overextended, perhaps this machine is only capable of a = WORKING=20 PERIOD of 15 seconds????
 
When I set it to 20, and move the boom, = it does go=20 to center, but because of the drift issue, it may not be capable of = HOLDING=20 CENTER. and perhaps this is stopping its sensitivity to all but the = larger=20 earthquakes????
 
On the good side the events it does = record, 6.2=20 Alaska and 7.8 China, look really good.    Thanks for = your=20 help.
Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Monday, May 26, 2008 = 12:51 PM
Subject: Re: Adjusting the = period

In a=20 message dated 2008/05/26, tchannel1@............=20 writes:

I plan on changing the period from 20 seconds to another = number,=20 not sure what that number will be.   What I want to see, = is how it=20 records at different period settings.
I know the = advantages of the=20 20 seconds.  The disadvantage is it misses many other smaller=20 earthquakes.
My question:  Before I try other period=20 numbers..........Have you tried this, and what were the = results?
I really don't = know what the=20 result would be.


Hi=20 Ted,

       If your Lehman is = working=20 properly, it should see all signals between the natural resonant = period, at=20 say 20 seconds and the low pass fiolter of your amplifier at 10=20 Hz.

       If you set the period = to 10=20 seconds, it will only record signals between 10 seconds and 10 Hz. It = will=20 have about 1/4 theprevious sensitivity to 20 second Love waves.=20

       You WILL NOT see any more = Earthquakes this way.

       = Remember=20 that Lehmans are directional? Could this be why you are missing some = quakes?=20 What quakes have you missed and why do you think you should have = recorded=20 them?
       An alternative is that = your=20 suspension may be sticking and preventing the arm from moving freely. = You may=20 then only see larger quakes.
       = Can you=20 remind me what suspensions, top and bottom, you are using,=20 please?
       Do you see the normal = 4 to 8=20 second microseisms OK?

      =20 Regards,

       Chris = Chapman=20 Subject: Re: Adjusting the period From: ChrisAtUpw@....... Date: Mon, 26 May 2008 22:05:40 EDT In a message dated 2008/05/27, tchannel1@............ writes: > The reason I know it is missing earthquakes is that I am running three > channels, One vertical spring, one tiltmeter, and one Lehman..........The Lehman > misses a lot of events the other two record. Hi Ted, OK. I accept that. Which compass direction is the boom please? > Yes I think part of it is directional. > > Would you think this could account for it..............The Lehman is set for > twenty seconds, but at twenty seconds, I think it is maxed out, that is to > say, I don't think I could get 21 seconds. > Even 20 seconds, for this unit, may be too much. I say that because it > drifts, sometimes falling 1/2" per week to the left or to the right. I adjust > it back to center and it stays only for a few days. > > Might it simply be this unit is not capable of working at 20 seconds. The > sticking you mentioned.........could this be because it is overextended, > perhaps this machine is only capable of a WORKING PERIOD of 15 seconds? No. If it works at 20 seconds, it should continue to do so. I am talking about stiction in the bearings. When we first tried out our school seismometer, they had not fitted a hard counterplate on the end of the Aluminum boom as I had specified, just a SS bearing on the vertical. The bearing made a tiny dent on the end of the boom and it did not respond properly. I then glued a SS scalpel blade to the boom and it was like a different instrument! What happens if you try to increase the period beyond 20 seconds? The original type Lehmans with a knife edge for the bottom bearing had difficulty getting beyond about 12 seconds. The knife edge either failed or dug into the counterface. A really dumb idea. > When I set it to 20, and move the boom, it does go to center, but because > of the drift issue, it may not be capable of HOLDING CENTER. and perhaps this > is stopping its sensitivity to all but the larger earthquakes? The instability could have several causes. One of these is the suspensions. You have not reminded me what you are using for the top and bottom suspensions! The drift with time could be related to temperature changes, maybe direct movement of the adjustment screws or movement over the ground due to differential expansion of the frame. What metal are the adjustement screws? Is the threaded insert / nut made from the same metal? Do you have three SS metal plates glued to the floor to support the adustment screws? Or are the screws in direct contact with the floor? I fit a nut and a WAVY spring washer on TOP of the baseplate, so that the three adjustment screws are ALWAYS held in tension. I am not 'being fussy'. The axis offset is maybe 0.32 degree - 0.1" if the vertical is 18" high. It is much more likely to be direct tilt of the floor. Where is the seismometer located? What sort of floor is it? Is the seismometer right next to an outside wall? Which direction does the wall face? What are the dimensions of the Lehman, what is the boom made of and what is the mass? Regards, Chris Chapman In a me= ssage dated 2008/05/27, tchannel1@............ writes:

The reason I know it is missing= earthquakes is that I am running three channels, One vertical spring, one t= iltmeter, and one Lehman..........The Lehman misses a lot of events the othe= r two record.


Hi Ted,

       OK. I accept that. Which compass direct= ion is the boom please?

Yes I think part of it is dire= ctional.

Would you think this could account for it..............The Lehman is set fo= r twenty seconds, but at twenty seconds, I think it is maxed out, that is to= say,  I don't think I could get 21 seconds.
Even 20 seconds, for this unit, may be too much.   I say that bec= ause it drifts, sometimes falling 1/2" per week to the left or to the right.=   I adjust it back to  center and it stays only for a few days.
Might it simply be this unit is not capable of working at 20 seconds. The s= ticking you mentioned.........could this be because it is overextended, perh= aps this machine is only capable of a WORKING PERIOD of 15 seconds?

       No. If it works at 20 seconds, it shou= ld continue to do so. I am talking about stiction in the bearings. When we f= irst tried out our school seismometer, they had not fitted a hard counterpla= te on the end of the Aluminum boom as I had specified, just a SS bearing on=20= the vertical. The bearing made a tiny dent on the end of the boom and it did= not respond properly. I then glued a SS scalpel blade to the boom and it wa= s like a different instrument!

       What happens if you try to increase the= period beyond 20 seconds? The original type Lehmans with a knife edge for t= he bottom bearing had difficulty getting beyond about 12 seconds. The knife=20= edge either failed or dug into the counterface. A really dumb idea.

When I set it to 20, and move= the boom, it does go to center, but because of the drift issue, it may not=20= be capable of HOLDING CENTER. and perhaps this is stopping its sensitivity t= o all but the larger earthquakes?


       The instability could have several caus= es. One of these is the suspensions. You have not reminded me what you are u= sing for the top and bottom suspensions!

       The drift with time could be related to= temperature changes, maybe direct movement of the adjustment screws or move= ment over the ground due to differential expansion of the frame. What metal=20= are the adjustement screws? Is the threaded insert / nut made from the same=20= metal? Do you have three SS metal plates glued to the floor to support the a= dustment screws? Or are the screws in direct contact with the floor? I fit a= nut and a WAVY spring washer on TOP of the baseplate, so that the three adj= ustment screws are ALWAYS held in tension.

       I am not 'being fussy'.  The axis=20= offset is maybe 0.32 degree - 0.1" if the vertical is 18" high.

       It is much more likely to be direct til= t of the floor. Where is the seismometer located? What sort of floor is it?=20= Is the seismometer right next to an outside wall? Which direction does the w= all face?

       What are the dimensions of the Lehman,=20= what is the boom made of and what is the mass?

       Regards,

       Chris Chapman Subject: 1018 steel for neo magnet damp & pickup coil web price variation From: "meredith lamb" paleoartifact@......... Date: Tue, 27 May 2008 11:07:33 -0600 Hi all, If you're interested in trying out the steel plates used with neodymium metals of recent PSN email notes and are looking for a steel source; here is a potential web source. I note that speedy metals.com sells 1018 grade steel at about 1/2 the price of onlinemetals.com. For example; the 1/4" thick X 2" x 3" plate that Chris Chapman sized for his coil, sells for $4.68 for FOUR pieces; versus $9.12 via On line metals.com; for the same quanity and size. Larger sizes will have corresponding higher prices. (The 4 pieces mentioned could potentially work for both a coil pickup and mass dampening needs.) Speedy metals can cut by the inch; while on line metals calls (the same) a "custom cut". Neither have a minimum order. Speedy metals does limit the maximum "inch" overall length to 105". Both companies usually have potentially a - zero to 1/8" oversize cut. I've not ordered anything from Speedy metals, so I can't say plus or minus; however, they sell on E-Bay and have a good reputation. For on line metals, I've had experience. They may take ~ 3 weeks to deliver. Which might prove to be true also with Speedy metals for the special/custom cut/sheared sizes. The "Kicker" for both is that they both prefer to ship via UPS....figure on a extra added high ~ $8.00 > charge or more (!). To be fair, USPS isn't likely any cheaper. Of course, one will still have to drill the holes in the plates and likely file/deburr such and etc. ***Unless you're replicating the size above, it would do well, to seriously consider a larger size of steel plates too "fit all" present or future coils/dampening expectations. The larger size would give more room for a variety of neo magnets, coils, dampening plate widths. http://www.speedymetals.com http://www.onlinemetals.com In Denver, I've checked four major hardware outlets, and none had any mild steel of the base thickness and width size/s above. There was limited 1/8" thick mild/bright/unknown steel and plenty of the lesser useful black high carbon stuff. None had any useful steel "L" brackets that would work either. High carbon angle iron "might" work, but its usually not very squared; and would require alot of file/grinding work. Scrap yards "might" yield something; but then you have to have the machinery for cutting and etc. Some scrap yards can cut too size for a extra charge. In the end; its likely the only means for the average limited tool person is to order via the web, and still have a punch, drill and file.... The cost seems to be all supply and demand (mainly the growing giants China-India), and transportation oil price related. Take care, Meredith Lamb Hi all,

If you're interested in trying out the steel plates used with neodymium metals of recent PSN email
notes and are looking for a steel source; here is a potential web source.

I note that speedy metals.com sells 1018 grade steel at about 1/2 the price of onlinemetals.com.

For example; the 1/4" thick X 2" x 3" plate that Chris Chapman sized for his coil, sells for $4.68 for FOUR
pieces; versus $9.12 via On line metals.com; for the same quanity and size.  Larger sizes will have
corresponding higher prices.  (The 4 pieces mentioned could potentially work for both a coil pickup and
mass dampening needs.)

Speedy metals can cut by the inch; while on line metals calls (the same) a "custom cut".  Neither have
a minimum order.  Speedy metals does limit the maximum "inch" overall length to 105".

Both companies usually have potentially a - zero to 1/8" oversize cut.

I've not ordered anything from Speedy metals, so I can't say plus or minus; however, they sell on E-Bay
and have a good reputation.

For on line metals, I've had experience.  They may take ~ 3 weeks to deliver.  Which might prove to be
true also with Speedy metals for the special/custom cut/sheared sizes.

The "Kicker" for both is that they both prefer to ship via UPS....figure on a extra added high ~ $8.00 > charge
or more (!).  To be fair, USPS isn't likely any cheaper.

Of course, one will still have to drill the holes in the plates and likely file/deburr such and etc.

***Unless you're replicating the size above, it would do well, to seriously consider a larger size of steel plates too "fit all"
present or future coils/dampening expectations.   The larger size would give more room for a variety of neo
magnets, coils, dampening plate widths. 

http://www.speedymetals.com

http://www.onlinemetals.com

In Denver, I've checked four major hardware outlets, and none had any mild steel of the base thickness and
width size/s above.  There was limited 1/8" thick mild/bright/unknown steel and plenty of the lesser useful black high carbon stuff.
None had any useful steel "L" brackets that would work either.  High carbon angle iron "might" work, but its usually
not very squared; and would require alot of file/grinding work.  Scrap yards "might" yield something; but then you have
to have the machinery for cutting and etc.  Some scrap yards can cut too size for a extra charge.  In the end; its
likely the only means for the average limited tool person is to order via the web, and still have a punch, drill and file....

The cost seems to be all supply and demand (mainly the growing giants China-India), and transportation oil price related.

Take care, Meredith Lamb






Subject: RE: 1018 steel for neo magnet damp & pickup coil web price variation From: "Gary Lindgren" gel@................. Date: Tue, 27 May 2008 10:40:06 -0700 Meredith, You should also check out http://www.metalsupermarkets.com/MSC-storefinder.aspx I ordered the steel plates for the magnets and dimensions were very good. Very good prices too. They also have aluminum. I'm lucky in that I have a store just a few miles away and can pickup a day later. But they have locations around the world. Check it out. Gary From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of meredith lamb Sent: Tuesday, May 27, 2008 10:08 AM To: psn-l@.............. Subject: 1018 steel for neo magnet damp & pickup coil web price variation Hi all, If you're interested in trying out the steel plates used with neodymium metals of recent PSN email notes and are looking for a steel source; here is a potential web source. I note that speedy metals.com sells 1018 grade steel at about 1/2 the price of onlinemetals.com. For example; the 1/4" thick X 2" x 3" plate that Chris Chapman sized for his coil, sells for $4.68 for FOUR pieces; versus $9.12 via On line metals.com; for the same quanity and size. Larger sizes will have corresponding higher prices. (The 4 pieces mentioned could potentially work for both a coil pickup and mass dampening needs.) Speedy metals can cut by the inch; while on line metals calls (the same) a "custom cut". Neither have a minimum order. Speedy metals does limit the maximum "inch" overall length to 105". Both companies usually have potentially a - zero to 1/8" oversize cut. I've not ordered anything from Speedy metals, so I can't say plus or minus; however, they sell on E-Bay and have a good reputation. For on line metals, I've had experience. They may take ~ 3 weeks to deliver. Which might prove to be true also with Speedy metals for the special/custom cut/sheared sizes. The "Kicker" for both is that they both prefer to ship via UPS....figure on a extra added high ~ $8.00 > charge or more (!). To be fair, USPS isn't likely any cheaper. Of course, one will still have to drill the holes in the plates and likely file/deburr such and etc. ***Unless you're replicating the size above, it would do well, to seriously consider a larger size of steel plates too "fit all" present or future coils/dampening expectations. The larger size would give more room for a variety of neo magnets, coils, dampening plate widths. http://www.speedymetals.com http://www.onlinemetals.com In Denver, I've checked four major hardware outlets, and none had any mild steel of the base thickness and width size/s above. There was limited 1/8" thick mild/bright/unknown steel and plenty of the lesser useful black high carbon stuff. None had any useful steel "L" brackets that would work either. High carbon angle iron "might" work, but its usually not very squared; and would require alot of file/grinding work. Scrap yards "might" yield something; but then you have to have the machinery for cutting and etc. Some scrap yards can cut too size for a extra charge. In the end; its likely the only means for the average limited tool person is to order via the web, and still have a punch, drill and file.... The cost seems to be all supply and demand (mainly the growing giants China-India), and transportation oil price related. Take care, Meredith Lamb

Meredith,

You should also check out http://www= ..metalsupermarkets.com/MSC-storefinder.aspx I ordered the steel plates for the magnets and dimensions were very = good. Very good prices too. They also have aluminum. I’m lucky in that I have = a store just a few miles away and can pickup a day later. But they have = locations around the world. Check it out.

Gary 

 

 

 

 

From:= psn-l-request@.............. [mailto:psn-l-request@............... On = Behalf Of meredith lamb
Sent: Tuesday, May 27, 2008 10:08 AM
To: psn-l@..............
Subject: 1018 steel for neo magnet damp & pickup coil web = price variation

 

Hi all,

If you're interested in trying out the steel plates used with neodymium = metals of recent PSN email
notes and are looking for a steel source; here is a potential web = source.

I note that speedy metals.com sells = 1018 grade steel at about 1/2 the price of onlinemetals.com.

For example; the 1/4" thick X 2" x 3" plate that Chris = Chapman sized for his coil, sells for $4.68 for FOUR
pieces; versus $9.12 via On line metals.com; for the same quanity and size.  Larger sizes will have
corresponding higher prices.  (The 4 pieces mentioned could = potentially work for both a coil pickup and
mass dampening needs.)

Speedy metals can cut by the inch; while on line metals calls (the same) = a "custom cut".  Neither have
a minimum order.  Speedy metals does limit the maximum = "inch" overall length to 105".

Both companies usually have potentially a - zero to 1/8" oversize = cut.

I've not ordered anything from Speedy metals, so I can't say plus or = minus; however, they sell on E-Bay
and have a good reputation.

For on line metals, I've had experience.  They may take ~ 3 weeks = to deliver.  Which might prove to be
true also with Speedy metals for the special/custom cut/sheared = sizes.

The "Kicker" for both is that they both prefer to ship via UPS....figure on a extra added high ~ $8.00 > charge
or more (!).  To be fair, USPS isn't likely any cheaper.

Of course, one will still have to drill the holes in the plates and = likely file/deburr such and etc.

***Unless you're replicating the size above, it would do well, to = seriously consider a larger size of steel plates too "fit all"
present or future coils/dampening expectations.   The larger = size would give more room for a variety of neo
magnets, coils, dampening plate widths. 

http://www.speedymetals.com

http://www.onlinemetals.com

In Denver, I've checked four major hardware outlets, and none had any = mild steel of the base thickness and
width size/s above.  There was limited 1/8" thick = mild/bright/unknown steel and plenty of the lesser useful black high carbon stuff.
None had any useful steel "L" brackets that would work = either.  High carbon angle iron "might" work, but its usually
not very squared; and would require alot of file/grinding work.  = Scrap yards "might" yield something; but then you have
to have the machinery for cutting and etc.  Some scrap yards can = cut too size for a extra charge.  In the end; its
likely the only means for the average limited tool person is to order = via the web, and still have a punch, drill and file....

The cost seems to be all supply and demand (mainly the growing giants China-India), and transportation oil price related.

Take care, Meredith Lamb





Subject: Re: Adjusting the period From: tchannel1@............ Date: Tue, 27 May 2008 13:51:20 -0600 Hi Chris, =20 >Which compass direction is the boom please? East/West > Where is the seismometer located? (Basement) What sort of floor is = it? (Concrete) (ss plates for the legs) >Is the seismometer right next to an outside wall? (Yes)=20 >Which direction does the wall face? (East/West) >What are the dimensions of the Lehman, what is the boom made of and = what is the mass? 36" boom 1/2" alum rod. Dim. 20"wide, 22" tall, 36" = long. The mass is 2.5# Alum cylinder Chris, I think I found the drift issue? I added a wing nut to lock the = legs after adjustment. I think they were moving over time? Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Monday, May 26, 2008 8:05 PM Subject: Re: Adjusting the period In a message dated 2008/05/27, tchannel1@............ writes: The reason I know it is missing earthquakes is that I am running = three channels, One vertical spring, one tiltmeter, and one = Lehman..........The Lehman misses a lot of events the other two record. Hi Ted, OK. I accept that. Which compass direction is the boom please? Yes I think part of it is directional. Would you think this could account for it..............The Lehman is = set for twenty seconds, but at twenty seconds, I think it is maxed out, = that is to say, I don't think I could get 21 seconds. Even 20 seconds, for this unit, may be too much. I say that = because it drifts, sometimes falling 1/2" per week to the left or to the = right. I adjust it back to center and it stays only for a few days. Might it simply be this unit is not capable of working at 20 = seconds. The sticking you mentioned.........could this be because it is = overextended, perhaps this machine is only capable of a WORKING PERIOD = of 15 seconds? No. If it works at 20 seconds, it should continue to do so. I = am talking about stiction in the bearings. When we first tried out our = school seismometer, they had not fitted a hard counterplate on the end = of the Aluminum boom as I had specified, just a SS bearing on the = vertical. The bearing made a tiny dent on the end of the boom and it did = not respond properly. I then glued a SS scalpel blade to the boom and it = was like a different instrument! What happens if you try to increase the period beyond 20 = seconds? The original type Lehmans with a knife edge for the bottom = bearing had difficulty getting beyond about 12 seconds. The knife edge = either failed or dug into the counterface. A really dumb idea. When I set it to 20, and move the boom, it does go to center, but = because of the drift issue, it may not be capable of HOLDING CENTER. and = perhaps this is stopping its sensitivity to all but the larger = earthquakes? The instability could have several causes. One of these is the = suspensions. You have not reminded me what you are using for the top and = bottom suspensions! The drift with time could be related to temperature changes, = maybe direct movement of the adjustment screws or movement over the = ground due to differential expansion of the frame. What metal are the = adjustement screws? Is the threaded insert / nut made from the same = metal? Do you have three SS metal plates glued to the floor to support = the adustment screws? Or are the screws in direct contact with the = floor? I fit a nut and a WAVY spring washer on TOP of the baseplate, so = that the three adjustment screws are ALWAYS held in tension.=20 I am not 'being fussy'. The axis offset is maybe 0.32 degree - = 0.1" if the vertical is 18" high. It is much more likely to be direct tilt of the floor. Where is = the seismometer located? What sort of floor is it? Is the seismometer = right next to an outside wall? Which direction does the wall face? What are the dimensions of the Lehman, what is the boom made of = and what is the mass? Regards, Chris Chapman
Hi Chris,    =
 
>Which compass direction is the boom = please?   East/West
 
> Where is the seismometer located?   =20 (Basement)  What sort of floor is it?   (Concrete) =  (ss=20 plates for the legs)
>Is the=20 seismometer right next to an outside wall?   (Yes)=20
>Which=20 direction does the wall face? (East/West)
 
>What=20 are the dimensions of the Lehman, what is the boom made of and what is = the=20 mass?  36" boom 1/2" alum rod.   Dim. 20"wide, 22" tall, = 36"=20 long.  The mass is 2.5# Alum cylinder
 
Chris, I=20 think I found the drift issue?  I added a wing nut to lock the legs = after=20 adjustment.  I think they were moving over = time?
 
Thanks, Ted
 
 
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Monday, May 26, 2008 8:05 = PM
Subject: Re: Adjusting the = period

In a=20 message dated 2008/05/27, tchannel1@............=20 writes:

The reason I know it is missing earthquakes is that I am = running=20 three channels, One vertical spring, one tiltmeter, and one=20 Lehman..........The Lehman misses a lot of events the other two=20 record.


Hi=20 Ted,

       OK. I accept that. = Which=20 compass direction is the boom please?

 Yes I think part of it is directional.

Would you think = this could=20 account for it..............The Lehman is set for twenty seconds, = but at=20 twenty seconds, I think it is maxed out, that is to say,  I = don't think=20 I could get 21 seconds.
Even 20 seconds, for this unit, may be too = much.  =20 I say that because it drifts, sometimes falling 1/2" per week to the = left or=20 to the right.  I adjust it back to  center and it stays = only for a=20 few days.

Might it simply be this unit is not capable of = working at 20=20 seconds. The sticking you mentioned.........could this be because it = is=20 overextended, perhaps this machine is only capable of a WORKING = PERIOD of 15=20 seconds?

       No. If=20 it works at 20 seconds, it should continue to do so. I am talking = about=20 stiction in the bearings. When we first tried out our school = seismometer, they=20 had not fitted a hard counterplate on the end of the Aluminum boom as = I had=20 specified, just a SS bearing on the vertical. The bearing made a tiny = dent on=20 the end of the boom and it did not respond properly. I then glued a SS = scalpel=20 blade to the boom and it was like a different=20 instrument!

       What happens = if you=20 try to increase the period beyond 20 seconds? The original type = Lehmans with a=20 knife edge for the bottom bearing had difficulty getting beyond about = 12=20 seconds. The knife edge either failed or dug into the counterface. A = really=20 dumb idea.

When I=20 set it to 20, and move the boom, it does go to center, but because = of the=20 drift issue, it may not be capable of HOLDING CENTER. and perhaps = this is=20 stopping its sensitivity to all but the larger=20 earthquakes?

       = The=20 instability could have several causes. One of these is the = suspensions. You=20 have not reminded me what you are using for the top and bottom=20 suspensions!

       The drift = with time=20 could be related to temperature changes, maybe direct movement of the=20 adjustment screws or movement over the ground due to differential = expansion of=20 the frame. What metal are the adjustement screws? Is the threaded = insert / nut=20 made from the same metal? Do you have three SS metal plates glued to = the floor=20 to support the adustment screws? Or are the screws in direct contact = with the=20 floor? I fit a nut and a WAVY spring washer on TOP of the baseplate, = so that=20 the three adjustment screws are ALWAYS held in tension.=20

       I am not 'being = fussy'.  The=20 axis offset is maybe 0.32 degree - 0.1" if the vertical is 18"=20 high.

       It is much more = likely to be=20 direct tilt of the floor. Where is the seismometer located? What sort = of floor=20 is it? Is the seismometer right next to an outside wall? Which = direction does=20 the wall face?

       What are = the=20 dimensions of the Lehman, what is the boom made of and what is the=20 mass?

      =20 Regards,

       Chris = Chapman=20 Subject: Re: Adjusting the period From: ChrisAtUpw@....... Date: Tue, 27 May 2008 16:40:43 EDT In a message dated 2008/05/27, tchannel1@............ writes: > >Is the seismometer right next to an outside wall? (Yes) > >Which direction does the wall face? (East/West) Hi Ted, A location close to a load bearing outside wall is likely to be effected by any movements of the wall, due to rainfall on the soil outside, the effect of the sun raising the wall temperature and also noise from winds. > >What are the dimensions of the Lehman, what is the boom made of and what > is the mass? 36" boom 1/2" alum rod. Dim. 20"wide, 22" tall, 36" long. The > mass is 2.5# Alum cylinder Thanks. What is the weight of the Aluminum cylinder, please - or alternatively it's length? Is it solid Al, 2.5" OD? > Chris, I think I found the drift issue? I added a wing nut to lock the > legs after adjustment. I think they were moving over time? That could well be the problem. Threads are cut at about a 60 degree angle and are rarely a tight fit. If the thread and the nut / threaded insert are not of the same material, you get differential expansion which slides the threads radially. Similarly, unless the adjusting screw is under tension, any differential expansion of the frame relative to the Earth underneath will try to tilt the thread and cause it to slip diagonally. It is preferable to use a wavy spring washer between the wing nut / lock nut and the frame to keep a fairly constant tension. This will not be much effected by the small amounts of differential expansion of the base and the bolt. Let us know if this cures your drift problems? Regards, Chris Chapman In a me= ssage dated 2008/05/27, tchannel1@............ writes:

>Is the seismometer right ne= xt to an outside wall?  (Yes)
>Which direction does the wall face? (East/West)


Hi Ted,

       A location close to a load bearing outs= ide wall is likely to be effected by any movements of the wall, due to rainf= all on the soil outside, the effect of the sun raising the wall temperature=20= and also noise from winds.

>What are the dimensions of= the Lehman, what is the boom made of and what is the mass?  36" boom 1= /2" alum rod.  Dim. 20"wide, 22" tall, 36" long.  The mass is 2.5#= Alum cylinder


       Thanks. What is the weight of the Alum= inum cylinder, please - or alternatively it's length? Is it solid Al, 2.5" O= D?

Chris, I think I found the dri= ft issue?  I added a wing nut to lock the legs after adjustment. =20= I think they were moving over time?


       That could well be the problem. Threads= are cut at about a 60 degree angle and are rarely a tight fit. If the threa= d and the nut / threaded insert are not of the same material, you get differ= ential expansion which slides the threads radially. Similarly, unless the ad= justing screw is under tension, any differential expansion of the frame rela= tive to the Earth underneath will try to tilt the thread and cause it to sli= p diagonally. It is preferable to use a wavy spring washer between the wing=20= nut / lock nut and the frame to keep a fairly constant tension. This will no= t be much effected by the small amounts of differential expansion of the bas= e and the bolt.

       Let us know if this cures your drift pr= oblems?

       Regards,

       Chris Chapman Subject: Re: Adjusting the period From: tchannel1@............ Date: Tue, 27 May 2008 17:15:57 -0600 Hi Chris, =20 >Is it solid Al, 2.5" OD? I meant to say 2.5 pounds, alum 3" x 3" = cylinder. Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Tuesday, May 27, 2008 2:40 PM Subject: Re: Adjusting the period In a message dated 2008/05/27, tchannel1@............ writes: >Is the seismometer right next to an outside wall? (Yes)=20 >Which direction does the wall face? (East/West) Hi Ted, A location close to a load bearing outside wall is likely to be = effected by any movements of the wall, due to rainfall on the soil = outside, the effect of the sun raising the wall temperature and also = noise from winds.=20 >What are the dimensions of the Lehman, what is the boom made of and = what is the mass? 36" boom 1/2" alum rod. Dim. 20"wide, 22" tall, 36" = long. The mass is 2.5# Alum cylinder Thanks. What is the weight of the Aluminum cylinder, please - = or alternatively it's length? Is it solid Al, 2.5" OD? Chris, I think I found the drift issue? I added a wing nut to lock = the legs after adjustment. I think they were moving over time? That could well be the problem. Threads are cut at about a 60 = degree angle and are rarely a tight fit. If the thread and the nut / = threaded insert are not of the same material, you get differential = expansion which slides the threads radially. Similarly, unless the = adjusting screw is under tension, any differential expansion of the = frame relative to the Earth underneath will try to tilt the thread and = cause it to slip diagonally. It is preferable to use a wavy spring = washer between the wing nut / lock nut and the frame to keep a fairly = constant tension. This will not be much effected by the small amounts of = differential expansion of the base and the bolt.=20 Let us know if this cures your drift problems? Regards, Chris Chapman
Hi Chris, 
 
>Is it solid Al, 2.5" = OD?   I meant to=20 say 2.5 pounds, alum 3" x 3" cylinder.
 
Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Tuesday, May 27, 2008 = 2:40 PM
Subject: Re: Adjusting the = period

In a=20 message dated 2008/05/27, tchannel1@............=20 writes:

>Is the seismometer right next to an outside = wall? =20 (Yes)
>Which direction does the wall face?=20 (East/West)

Hi=20 Ted,

       A location close to a = load=20 bearing outside wall is likely to be effected by any movements of the = wall,=20 due to rainfall on the soil outside, the effect of the sun raising the = wall=20 temperature and also noise from winds.

>What are the dimensions of the Lehman, what is the = boom made=20 of and what is the mass?  36" boom 1/2" alum rod.  Dim. = 20"wide,=20 22" tall, 36" long.  The mass is 2.5# Alum cylinder

       Thanks.=20 What is the weight of the Aluminum cylinder, please - or alternatively = it's=20 length? Is it solid Al, 2.5" OD?

 Chris, I think I found the drift issue?  I added a = wing nut=20 to lock the legs after adjustment.  I think they were moving = over=20 time?

      =20 That could well be the problem. Threads are cut at about a 60 degree = angle and=20 are rarely a tight fit. If the thread and the nut / threaded insert = are not of=20 the same material, you get differential expansion which slides the = threads=20 radially. Similarly, unless the adjusting screw is under tension, any=20 differential expansion of the frame relative to the Earth underneath = will try=20 to tilt the thread and cause it to slip diagonally. It is preferable = to use a=20 wavy spring washer between the wing nut / lock nut and the frame to = keep a=20 fairly constant tension. This will not be much effected by the small = amounts=20 of differential expansion of the base and the bolt.=20

       Let us know if this cures = your=20 drift problems?

      =20 Regards,

       Chris = Chapman=20 Subject: Big earthquake in Iceland From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Thu, 29 May 2008 16:02:19 +0000 Hi all At 15:55 there was a really big earthquake in Iceland. The size was at least ML5.5 up to ML6.1, but I am wating for better eastimate on size soon. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: ping =?UTF-8?B?SsOzbiBGcsOtbWFubg==?= From: Mark Robinson mark.robinson@............... Date: Fri, 30 May 2008 04:11:57 +1200 Mag 6.1 50km from Reykjavik: http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008sqba.php The BBC was somewhat more dramatic talking about a magnitude in the high 6s. (some mail server thinks I am spamming) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: ping =?UTF-8?B?SsOzbiBGcsOtbWFubg==?= From: ian ian@........... Date: Thu, 29 May 2008 17:16:37 +0100 Hi, got it here, though a low signal trace. Either my Lehman is pointing the wrong way or is was in one of its "deaf" modes again. Cheers Ian ------------------------------------------------------------------------ ------------------------------------------------------------------------ Mark Robinson wrote: > Mag 6.1 50km from Reykjavik: > > http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008sqba.php > > The BBC was somewhat more dramatic talking about a magnitude in the high 6s. > > > (some mail server thinks I am spamming) > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Big earthquake in Iceland From: Canie canie@........... Date: Thu, 29 May 2008 09:16:53 -0700 Is this quake in the area you said you were expecting a large one? It looks like it might be in that area that you=20 said was having a swarm - your note from 5/22: >Given the earthquake swarm pattern I am expecting a earthquake there >that is ML4.0 up to ML5.5, but I doubt it is going to get bigger then >mag 5.5. I expect this earthquake to happen in next two days at least, >but this might take longer time to happen. A little bigger than expected and a few days later - Good Call! Canie At 09:02 AM 5/29/2008, J=F3n Fr=EDmann wrote: >Hi all > >At 15:55 there was a really big earthquake in Iceland. The size was at >least ML5.5 up to ML6.1, but I am wating for better eastimate on size >soon. > >Regards. >-- >J=F3n Fr=EDmann >http://www.jonfr.com >http://earthquakes.jonfr.com >http://www.net303.net >http://www.mobile-coverage.com/ > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Big earthquake in Iceland From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Thu, 29 May 2008 16:30:14 +0000 Hi That area was more to the north of the current episcenter. However, the activite two the north of current epicenter might have been a clue to this earthquake. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Big earthquake in Iceland From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Thu, 29 May 2008 16:52:40 +0000 Hi all I have submitted the traces of the earthqukes to the psn web site. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: =?utf-8?Q?Re:_ping_J=C3=B3n_Fr=C3=ADmann?= From: tchannel1@............ Date: Thu, 29 May 2008 12:39:41 -0600 Hi, Got it nice and clear, here in Boise Idaho, on my Lehman pointing East and West, nothing on my vertical or North South Tiltmeter. Immg in Boise got it on their Lehman pointing North South. Ted ----- Original Message ----- From: "ian" To: Sent: Thursday, May 29, 2008 10:16 AM Subject: Re: ping Jón Frímann > Hi, > > got it here, though a low signal trace. Either my Lehman is pointing the > wrong way or is was in one of its "deaf" modes again. > > Cheers > > Ian > ------------------------------------------------------------------------ > > > > > > > > > > ------------------------------------------------------------------------ > > > > > > Mark Robinson wrote: >> Mag 6.1 50km from Reykjavik: >> >> http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008sqba.php >> >> The BBC was somewhat more dramatic talking about a magnitude in the high >> 6s. >> >> >> (some mail server thinks I am spamming) >> __________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> To leave this list email PSN-L-REQUEST@.............. with the body of >> the message (first line only): unsubscribe >> See http://www.seismicnet.com/maillist.html for more information. >> >> >> > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of the > message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: ping =?ISO-8859-1?Q?J=F3n?= =?ISO-8859-1?Q?_Fr=EDmann?= From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Thu, 29 May 2008 19:39:10 +0000 Hi all The movment of the earthquake was N-S, far as I can tell. I've been recording a lot of aftershocks since the big earthquake, there number of earthquakes is well above 100 and it is still going up. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Aftershocks From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Thu, 29 May 2008 23:00:37 +0000 Hi all I have started to post in traces from the aftershocks after the big earthquake today. This is just the start of it. I am still expecting a earthquake aftershock of mag 5.5 at least soon. Not sure when, but it can happen at any time. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Update on the earthquake From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Fri, 30 May 2008 12:19:58 +0000 Hi all Since yesterday there have been over 1000 aftershocks and there have been new hot spring area opening up in the area close to the epicenter of the earthquake. But there is a active hot spring area near the town of Hverager=F0i. I expect the aftershocks to continue in the next few days or weeks. There might be aftershocks that might be bigger then mag 4.5. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Directional characteristics of a "lehman type" sensor- From: "Connie & Jim Lehman" lehmancj@........... Date: Fri, 30 May 2008 13:25:09 -0400 PSN friends--I have noted several references to directional performance = on a typical 15-20 sec "Lehman" design. It was our observation that = very few quakes were blocked out due to orientation. One summer when = mictoseisms are lowest (here in Virginia) we ran two systems with booms = at right angles, N-S & E-W. We copied 66 events in two months. There = were signatures in both orientations--(excepting for a half-dozen small = events) and we noted the predictable comparisons with incoming P,S, & L = wave fronts. P waves show strong coming in broadside. S waves show = strongest coming in off the end. Likewise the Surface waves -S show a = distinctive difference whether they be Love waves or Raleigh. You = simply cannot hide from a readable event due to orientation. This test was made with systems having no filtering excepting to = remove mechanical room noise typical in a building, and 60 hz AC. We = were satisfied the generalizations above were verified, as we copied = several events (Alaskan or thereabouts--coming into our booms at 45 = degrees) which appeared identical on our n-s,e-w readouts. Running two = long period systems is a luxury now, but in earlier days of the big = bulky worldwide sensors, dual copy was standard--with few stations to = get a tag on direction of event. Here in VA. we usually ran our system broadside a few degrees off E-W = to accent the events of South Pacific, but any South American events of = size would boom right in with lower P waves and heavy S wave signatures. Another side effect of noting amplitude of S or surface wave = arrivals--one can tell whether the event has a shallow focus--less than = 30 km, or a deep focus of several hundred km--even before you are told!! I hope this is informative. Jim Lehman
PSN friends--I have noted several = references to=20 directional performance on a typical 15-20 sec "Lehman" design.  It = was our=20 observation that very few quakes  were blocked out due to=20 orientation.  One summer when mictoseisms are lowest (here in = Virginia) we=20 ran two systems with booms at right angles, N-S & E-W.  We = copied 66=20 events in two months.  There were signatures in both=20 orientations--(excepting for a half-dozen small events) and we = noted the=20 predictable comparisons with incoming P,S, & L wave fronts.  P=20 waves show strong coming in broadside.  S waves show strongest = coming=20 in off the end.  Likewise the Surface waves -S show = a distinctive=20 difference whether they be Love waves or Raleigh.  You simply = cannot hide=20 from a readable event due to orientation.
   This test was made with = systems having=20 no filtering excepting to remove mechanical room noise typical in a = building, and 60 hz AC.  We were satisfied the generalizations = above were=20 verified, as we copied several events (Alaskan or thereabouts--coming = into our=20 booms at 45 degrees) which appeared identical on our n-s,e-w = readouts. =20 Running two long period systems is a luxury now, but in earlier days of = the big=20 bulky worldwide sensors, dual copy was standard--with few stations = to get a=20 tag on direction of event.
  Here in VA. we usually ran our = system=20 broadside a few degrees off E-W to accent the events of South Pacific, = but any=20 South American events of size would boom right in with lower P waves and = heavy S=20 wave signatures.
   Another side effect of = noting=20 amplitude of S or surface wave arrivals--one can tell whether the event = has a=20 shallow focus--less than 30 km, or a deep focus of several hundred = km--even=20 before you are told!!
   I hope this is = informative.  Jim=20 Lehman
   =
Subject: Re: Directional characteristics of a "lehman type" sensor- From: tchannel1@............ Date: Fri, 30 May 2008 11:46:32 -0600 Hi Jim, Thanks for this information. I have one Lehman N/S and one = E/W, and their performance agrees with your findings. There may be = differences due to orientation, but I do not see them. Ted ----- Original Message -----=20 From: Connie & Jim Lehman=20 To: psn-l@................. Sent: Friday, May 30, 2008 11:25 AM Subject: Directional characteristics of a "lehman type" sensor- PSN friends--I have noted several references to directional = performance on a typical 15-20 sec "Lehman" design. It was our = observation that very few quakes were blocked out due to orientation. = One summer when mictoseisms are lowest (here in Virginia) we ran two = systems with booms at right angles, N-S & E-W. We copied 66 events in = two months. There were signatures in both orientations--(excepting for = a half-dozen small events) and we noted the predictable comparisons with = incoming P,S, & L wave fronts. P waves show strong coming in broadside. = S waves show strongest coming in off the end. Likewise the Surface = waves -S show a distinctive difference whether they be Love waves or = Raleigh. You simply cannot hide from a readable event due to = orientation. This test was made with systems having no filtering excepting to = remove mechanical room noise typical in a building, and 60 hz AC. We = were satisfied the generalizations above were verified, as we copied = several events (Alaskan or thereabouts--coming into our booms at 45 = degrees) which appeared identical on our n-s,e-w readouts. Running two = long period systems is a luxury now, but in earlier days of the big = bulky worldwide sensors, dual copy was standard--with few stations to = get a tag on direction of event. Here in VA. we usually ran our system broadside a few degrees off = E-W to accent the events of South Pacific, but any South American events = of size would boom right in with lower P waves and heavy S wave = signatures. Another side effect of noting amplitude of S or surface wave = arrivals--one can tell whether the event has a shallow focus--less than = 30 km, or a deep focus of several hundred km--even before you are told!! I hope this is informative. Jim Lehman
Hi Jim,  Thanks for this=20 information.   I have one Lehman N/S and one E/W, and their=20 performance agrees with your findings.  There may be = differences due=20 to orientation, but I do not see them.
 
Ted
----- Original Message -----
From:=20 Connie &=20 Jim Lehman
Sent: Friday, May 30, 2008 = 11:25 AM
Subject: Directional = characteristics of a=20 "lehman type" sensor-

PSN friends--I have noted several = references to=20 directional performance on a typical 15-20 sec "Lehman" design.  = It was=20 our observation that very few quakes  were blocked out due to=20 orientation.  One summer when mictoseisms are lowest (here in = Virginia)=20 we ran two systems with booms at right angles, N-S & E-W.  We = copied=20 66 events in two months.  There were signatures in both=20 orientations--(excepting for a half-dozen small events) and we = noted the=20 predictable comparisons with incoming P,S, & L wave fronts.  = P=20 waves show strong coming in broadside.  S waves show = strongest=20 coming in off the end.  Likewise the Surface waves -S show=20 a distinctive difference whether they be Love waves or = Raleigh.  You=20 simply cannot hide from a readable event due to = orientation.
   This test was made with = systems=20 having no filtering excepting to remove mechanical room noise = typical in=20 a building, and 60 hz AC.  We were satisfied the generalizations = above=20 were verified, as we copied several events (Alaskan or = thereabouts--coming=20 into our booms at 45 degrees) which appeared identical on our n-s,e-w=20 readouts.  Running two long period systems is a luxury now, but = in=20 earlier days of the big bulky worldwide sensors, dual copy was=20 standard--with few stations to get a tag on direction of = event.
  Here in VA. we usually ran our = system=20 broadside a few degrees off E-W to accent the events of South Pacific, = but any=20 South American events of size would boom right in with lower P waves = and heavy=20 S wave signatures.
   Another side effect of = noting=20 amplitude of S or surface wave arrivals--one can tell whether the = event has a=20 shallow focus--less than 30 km, or a deep focus of several hundred = km--even=20 before you are told!!
   I hope this is = informative. =20 Jim Lehman
  =20
Subject: My sticking Lehman? From: tchannel1@............ Date: Fri, 30 May 2008 12:07:27 -0600 Hi Chris, and Others, My problems with my new Lehman, have been = resolved, I think...... I had one obvious problem: At 20 seconds the arm would drift, left or = right and I would need to reset it every two days. The legs were = threaded into the base, but loose, a lot of free play. Knowing this I = added a standard nut to lock the leg, which I would only finger tighten, = this had always worked in the past. What was happening is that the leg was moving itself. Chris pointed = out using two different materials would cause this. But on other units = it was never an issue. In this case I removed the hex nut and added a wing nut. After adj. I = finger tighten the wing nut, nice and tight, and it has not drifted = since. The second problem: At 20 seconds, I was missing all but large = earthquakes, those were coming through just fine. Chris suggest the = arm might be sticking. I could see nothing which resembled sticking. I don't know if this was the cause and effect, but I fixed it: First this is not the best Lehman I have ever built. Its okay, and with = little effort I got the 20 seconds, but I am not sure I could get 22. = However at 20 something was sticking. =20 I think at 20 it was so near infinity, it was almost flat. At infinity = it would never move to center, the arm would just stay where you placed = it. At 20 seconds it would move to center, if the event was large = enough to overcome the inertia, but smaller earthquakes would not do = this.=20 I reduce the period to 15 seconds, and it is working great. I record = 6.2M Iceland, and 4.1M California. I could, now increase the period to = 16,17,18 etc and retest. I will see how it performs at 15 for a while. Just wanted to share. Thanks for the help. Ted
Hi Chris, and Others,   My = problems with=20 my new Lehman, have been resolved, I think......
 
I had one obvious problem:   = At 20=20 seconds the arm would drift, left or right and I would need to reset it = every=20 two days.  The legs were threaded into the base, but loose, a lot = of free=20 play.  Knowing this I added a standard nut to lock the leg, which I = would=20 only finger tighten, this had always worked in the past.
 
What was happening is that the leg was = moving=20 itself.   Chris pointed out using two different materials = would cause=20 this.  But on other units it was never an issue.
In this case I removed the hex nut and = added a wing=20 nut.  After adj. I finger tighten the wing nut, nice and tight, and = it has=20 not drifted since.
 
The second problem:  At 20 = seconds, I was=20 missing all but large earthquakes, those were coming through just=20 fine.   Chris suggest the arm might be sticking.  I could = see=20 nothing which resembled sticking.
 
I don't know if this was the cause and = effect, but=20 I fixed it:
 
First this is not the best Lehman I = have ever=20 built.  Its okay, and with little effort I got the 20 seconds, but = I am not=20 sure I could get 22.  However at 20 something was sticking. =20
I think at 20 it was so near infinity, = it was=20 almost flat.   At infinity it would never move to center, = the arm=20 would just stay where you placed it.  At 20 seconds it would move = to=20 center, if the event was large enough to overcome the inertia, but = smaller=20 earthquakes would not do this.
 
I reduce the period to 15 seconds, and = it is=20 working great.  I record 6.2M Iceland, and 4.1M = California.   I=20 could, now increase the period to 16,17,18 etc and retest.   I = will=20 see how it performs at 15 for a while.
 
Just wanted to share.
 
Thanks for the help. =20 Ted
Subject: Re: 1018 steel for neo magnet damp & pickup coil web price variation From: "meredith lamb" paleoartifact@......... Date: Fri, 30 May 2008 13:15:04 -0600 Hi Gary, I went to the site and via their electronic form, asked for a quote; but after 4 days they have never replied. Perhaps like you mentioned it "maybe" primarily a local pickup source; if one has one nearby. The nearest web place I went too; their facility is a state away. Meredith On Tue, May 27, 2008 at 11:40 AM, Gary Lindgren wrote: > Meredith, > > You should also check out > http://www.metalsupermarkets.com/MSC-storefinder.aspx I ordered the steel > plates for the magnets and dimensions were very good. Very good prices too. > They also have aluminum. I'm lucky in that I have a store just a few miles > away and can pickup a day later. But they have locations around the world. > Check it out. > > Gary > > > > > > > > > Hi Gary,

I went to the site and via their electronic form, asked for a quote; but after 4 days they have never replied.  Perhaps like you mentioned
it "maybe" primarily a local pickup source; if one has one nearby.  The nearest web place I went too; their facility
is a state away.

Meredith

On Tue, May 27, 2008 at 11:40 AM, Gary Lindgren <gel@.................> wrote:

Meredith,

You should also check out http://www.metalsupermarkets.com/MSC-storefinder.aspx I ordered the steel plates for the magnets and dimensions were very good. Very good prices too. They also have aluminum. I'm lucky in that I have a store just a few miles away and can pickup a day later. But they have locations around the world. Check it out.

Gary 

 

 

 

 


Subject: Precision made; but cheapest magnet holding assembly From: "meredith lamb" paleoartifact@......... Date: Fri, 30 May 2008 14:09:50 -0600 Hi all, Actually; I think the cheapest metal magnet holding assembly, particularly for most of us without the tools to make metal plates; is to just buy a pair of machinist "1-2-3" (1" x 2" x 3") blocks from like, Discount machine on E-Bay. They cost ~$7 for a pair, plus the usual ~$10 > shipping cost. Thats 2 blocks for the one price. The more you buy in one quanity buy session; the cheaper the total shipping of course. Just add the bolts/nuts and/or spacer/standoffs for whatever you have that would work for that metal size AND whatever size magnets can fit it also. They are 1" thick x 2" height x 3" length in dimension. They have 23 holes in them; five tapped holes and 18 untapped holes. One can easily use 1/4" bolts in the untapped corner holes. They are precision ground hardened tool steel. The thickness will likely absorb most if not all magnetic effect from the mounted magnets as sensed on the opposite side/s....after all its 1" thick. As thick as they are, and with using a solid standoff/spacer, you probably won't need but 2 of such, instead of 4 bolts/nuts. If you need more magnet space (for your seismometer masterpiece/s); one can add more of the same side by side (~4 x 6, or 6 x 4") with long enough bolts/nuts to go through the pair side by side. The thickness itself makes for a extremely rigid and square overall frame and one can easily bolt it down (throught the 1" pre-drilled steel) into your seismometer base plate vertically or horizontally. On Ebay search, just enter "123 block", and you'll see them. Their is a variety of sellers over time, but Discount Machine seems the cheapest at the moment. They are probably all Tawain or China made; but the quality is much more than good enough for this purpose. Meredith Lamb Hi all,

Actually; I think the cheapest metal magnet holding assembly, particularly for most of us without the tools
to make metal plates; is to just buy a pair of machinist "1-2-3" (1" x 2" x 3") blocks from like,
Discount machine on E-Bay.  They cost ~$7 for a pair, plus the usual ~$10 > shipping cost.  Thats 2
blocks for the one price.  The more you buy in one quanity buy session; the cheaper the total shipping
of course.  Just add the bolts/nuts and/or spacer/standoffs for whatever you have that would work for
that metal size AND whatever size magnets can fit it also.

They are 1" thick x 2" height x 3" length in dimension.  They have 23 holes in them; five tapped holes and 18 untapped
holes.  One can easily use 1/4" bolts in the untapped corner holes.  They are precision ground hardened tool steel.
The thickness will likely absorb most if not all magnetic effect from the mounted magnets as sensed on the opposite
side/s....after all its 1" thick.

As thick as they are, and with using a solid standoff/spacer, you probably won't need but 2 of such, instead
of 4 bolts/nuts.

If you need more magnet space (for your seismometer masterpiece/s); one can add more of the same
side by side (~4 x 6, or 6 x 4") with long enough bolts/nuts to go through the pair side by side.

The thickness itself makes for a extremely rigid and square overall frame and one can easily bolt it down
(throught the 1" pre-drilled steel) into your seismometer base plate vertically or horizontally.

On Ebay search, just enter "123 block", and you'll see them.  Their is a variety of sellers over time, but
Discount Machine seems the cheapest at the moment.

They are probably all Tawain or China made; but the quality is much more than good enough for this
purpose.

Meredith Lamb


Subject: RE: 1018 steel for neo magnet damp & pickup coil web price variation From: "Gary Lindgren" gel@................. Date: Fri, 30 May 2008 13:32:36 -0700 Meredith, Sorry you did not get a quote reply. But you may want to check your spam folder. The quote may have dropped in there. That happened to one of my quote requests. My experience has been that a quote is answered in 15 minutes during the workday. On Tuesday I goofed on one of parts for the Lehman and sent in a quote request at 11:00AM, 15 minutes later I received a quote and liked the price and responded with OK and asked when I can pickup. Five minutes later, they said anytime to pickup. Two hours later I had the parts in hand. I would guess Metal Supermarkets is a franchise operation and each owner is his own man and how he operates. I would follow-up and make sure you get a reason for no-response. Gary From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of meredith lamb Sent: Friday, May 30, 2008 12:15 PM To: psn-l@.............. Subject: Re: 1018 steel for neo magnet damp & pickup coil web price variation Hi Gary, I went to the site and via their electronic form, asked for a quote; but after 4 days they have never replied. Perhaps like you mentioned it "maybe" primarily a local pickup source; if one has one nearby. The nearest web place I went too; their facility is a state away. Meredith On Tue, May 27, 2008 at 11:40 AM, Gary Lindgren wrote: Meredith, You should also check out http://www.metalsupermarkets.com/MSC-storefinder.aspx I ordered the steel plates for the magnets and dimensions were very good. Very good prices too. They also have aluminum. I'm lucky in that I have a store just a few miles away and can pickup a day later. But they have locations around the world. Check it out. Gary

Meredith,

Sorry you did not get a quote reply. But you may want to = check your spam folder. The quote may have dropped in there. That happened to = one of my quote requests. My experience has been that a quote is answered in 15 = minutes during the workday. On Tuesday I goofed on one of parts for the Lehman = and sent in a quote request at 11:00AM, 15 minutes later I received a quote and = liked the price and responded with OK and asked when I can pickup. Five = minutes later, they said anytime to pickup. Two hours later I had the parts in hand. I = would guess Metal Supermarkets is a franchise operation and each owner is his = own man and how he operates. I would follow-up and make sure you get a reason = for no-response.

Gary

 

From:= psn-l-request@.............. [mailto:psn-l-request@............... On = Behalf Of meredith lamb
Sent: Friday, May 30, 2008 12:15 PM
To: psn-l@..............
Subject: Re: 1018 steel for neo magnet damp & pickup coil web = price variation

 

Hi Gary,

I went to the site and via their electronic form, asked for a quote; but = after 4 days they have never replied.  Perhaps like you mentioned
it "maybe" primarily a local pickup source; if one has one nearby.  The nearest web place I went too; their facility
is a state away.

Meredith

 

Subject: RE: Precision made; but cheapest magnet holding assembly From: "Gary Lindgren" gel@................. Date: Fri, 30 May 2008 13:54:50 -0700 Meredith, Your thought that maybe the 1-2-3 blocks are made in China reminded me that a few weeks ago I was looking for a coil winder on eBay and found one that looked good. Only $35 and it comes from China. The shipping is costly at $60, but 3 days later I had it in my hand. Oh that globalization thing!!! Gary From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of meredith lamb Sent: Friday, May 30, 2008 1:10 PM To: psn-l@.............. Subject: Precision made; but cheapest magnet holding assembly Hi all, Actually; I think the cheapest metal magnet holding assembly, particularly for most of us without the tools to make metal plates; is to just buy a pair of machinist "1-2-3" (1" x 2" x 3") blocks from like, Discount machine on E-Bay. They cost ~$7 for a pair, plus the usual ~$10 > shipping cost. Thats 2 blocks for the one price. The more you buy in one quanity buy session; the cheaper the total shipping of course. Just add the bolts/nuts and/or spacer/standoffs for whatever you have that would work for that metal size AND whatever size magnets can fit it also. They are 1" thick x 2" height x 3" length in dimension. They have 23 holes in them; five tapped holes and 18 untapped holes. One can easily use 1/4" bolts in the untapped corner holes. They are precision ground hardened tool steel. The thickness will likely absorb most if not all magnetic effect from the mounted magnets as sensed on the opposite side/s....after all its 1" thick. As thick as they are, and with using a solid standoff/spacer, you probably won't need but 2 of such, instead of 4 bolts/nuts. If you need more magnet space (for your seismometer masterpiece/s); one can add more of the same side by side (~4 x 6, or 6 x 4") with long enough bolts/nuts to go through the pair side by side. The thickness itself makes for a extremely rigid and square overall frame and one can easily bolt it down (throught the 1" pre-drilled steel) into your seismometer base plate vertically or horizontally. On Ebay search, just enter "123 block", and you'll see them. Their is a variety of sellers over time, but Discount Machine seems the cheapest at the moment. They are probably all Tawain or China made; but the quality is much more than good enough for this purpose. Meredith Lamb

Meredith,

Your thought that maybe the 1-2-3 blocks are made in = China reminded me that a few weeks ago I was looking for a coil winder on eBay = and found one that looked good. Only $35 and it comes from China. The = shipping is costly at $60, but 3 days later I had it in my hand. Oh that = globalization thing!!!

Gary

 

 

 

 

From:= psn-l-request@.............. [mailto:psn-l-request@............... On = Behalf Of meredith lamb
Sent: Friday, May 30, 2008 1:10 PM
To: psn-l@..............
Subject: Precision made; but cheapest magnet holding = assembly

 

Hi all,

Actually; I think the cheapest metal magnet holding assembly, = particularly for most of us without the tools
to make metal plates; is to just buy a pair of machinist = "1-2-3" (1" x 2" x 3") blocks from like,
Discount machine on E-Bay.  They cost ~$7 for a pair, plus the = usual ~$10 > shipping cost.  Thats 2
blocks for the one price.  The more you buy in one quanity buy = session; the cheaper the total shipping
of course.  Just add the bolts/nuts and/or spacer/standoffs for = whatever you have that would work for
that metal size AND whatever size magnets can fit it also.

They are 1" thick x 2" height x 3" length in = dimension.  They have 23 holes in them; five tapped holes and 18 untapped
holes.  One can easily use 1/4" bolts in the untapped corner holes.  They are precision ground hardened tool steel.
The thickness will likely absorb most if not all magnetic effect from = the mounted magnets as sensed on the opposite
side/s....after all its 1" thick.

As thick as they are, and with using a solid standoff/spacer, you = probably won't need but 2 of such, instead
of 4 bolts/nuts.

If you need more magnet space (for your seismometer masterpiece/s); one = can add more of the same
side by side (~4 x 6, or 6 x 4") with long enough bolts/nuts to go = through the pair side by side.

The thickness itself makes for a extremely rigid and square overall = frame and one can easily bolt it down
(throught the 1" pre-drilled steel) into your seismometer base = plate vertically or horizontally.

On Ebay search, just enter "123 block", and you'll see = them.  Their is a variety of sellers over time, but
Discount Machine seems the cheapest at the moment.

They are probably all Tawain or China made; but the quality is much more = than good enough for this
purpose.

Meredith Lamb

Subject: RE: 1018 steel for neo magnet damp & pickup coil web price variation From: "Gary Lindgren" gel@................. Date: Fri, 30 May 2008 14:18:09 -0700 Meredith, Send your RFQ to bill@................. Bill is my Metal Supermarkets contact at the Redwood City CA shop. They make local deliveries with their truck and ship via UPS or common carrier. You still have a couple hours for a quote today. Gary From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of meredith lamb Sent: Friday, May 30, 2008 12:15 PM To: psn-l@.............. Subject: Re: 1018 steel for neo magnet damp & pickup coil web price variation Hi Gary, I went to the site and via their electronic form, asked for a quote; but after 4 days they have never replied. Perhaps like you mentioned it "maybe" primarily a local pickup source; if one has one nearby. The nearest web place I went too; their facility is a state away. Meredith On Tue, May 27, 2008 at 11:40 AM, Gary Lindgren wrote: Meredith, You should also check out http://www.metalsupermarkets.com/MSC-storefinder.aspx I ordered the steel plates for the magnets and dimensions were very good. Very good prices too. They also have aluminum. I'm lucky in that I have a store just a few miles away and can pickup a day later. But they have locations around the world. Check it out. Gary

Meredith,

Send your RFQ to bill@................. Bill = is my Metal Supermarkets contact at the Redwood City CA shop. They make local = deliveries with their truck and ship via UPS or common carrier. You still have a = couple hours for a quote today.

Gary

 

 

 

 

From:= psn-l-request@.............. [mailto:psn-l-request@............... On = Behalf Of meredith lamb
Sent: Friday, May 30, 2008 12:15 PM
To: psn-l@..............
Subject: Re: 1018 steel for neo magnet damp & pickup coil web = price variation

 

Hi Gary,

I went to the site and via their electronic form, asked for a quote; but = after 4 days they have never replied.  Perhaps like you mentioned
it "maybe" primarily a local pickup source; if one has one = nearby.  The nearest web place I went too; their facility
is a state away.

Meredith

 

Subject: Update on the earthquake From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Fri, 30 May 2008 21:59:24 +0000 Hi all Here are some data that I have collected since yesterday earthquake. This is mostly traces along side maps from IMO that I have saved for keeping. http://www.jonfr.com/myndir/v/geology/sisz2008/ Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://earthquakes.jonfr.com http://www.net303.net http://www.mobile-coverage.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: My sticking Lehman? From: ChrisAtUpw@....... Date: Fri, 30 May 2008 18:53:30 EDT In a message dated 2008/05/30, tchannel1@............ writes: > The second problem: At 20 seconds, I was missing all but large > earthquakes, those were coming through just fine. Chris suggest the arm might be > sticking. I could see nothing which resembled sticking. Hi Ted, 1) what top bearing / flexure are you using? 2) what bottom bearing / flexure are you using? 3) have you checked both the coil and the damping magnets for whiskers? They tend to grow with time and can cause the beam to