Subject: Re: Problem sending event files From: Robert Laney faultshake@......... Date: Sat, 2 Jul 2005 16:42:15 -0700 (PDT) Hi Bob: Many thanks for the suggestion. I had thought about sending files this way, but had never done it. It sure is a puzzle why it won't work through Winquake like I have done for several years. The surprises using AOL! Regards, Bob Bobhelenmcclure@....... wrote: On Thu, 23 Jun 2005, Robert Laney wrote: >I have run into a problem trying to submit an email of event files via AOL.< Hi Bob, Have you tried making up your own email with the event file attached, rather than than trying to send it via WinQuake? I am an AOL subscriber and have no problems sending that way. About a month ago, I experienced difficulties, but Larry found and fixed the problem. I have never attempted to send files from WinQuake itself. You cannot send more than one file at a time!!! AOL always makes a ZIP of multiple attachments, and seismicnet's server does not accept ZIP files. Regards, Bob McClure Locust Valley, NY, USA 40.882N 73.582W __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
Hi Bob:
 
Many thanks for the suggestion.  I had thought about sending files this way, but had never done it.  It sure is a puzzle why it won't work through Winquake like I have done for several years.  The surprises using AOL!
 
Regards,
 
Bob
 


Bobhelenmcclure@....... wrote:
On Thu, 23 Jun 2005, Robert Laney wrote:
>I have run into a problem trying to submit an email of event files via AOL.<

Hi Bob,

  Have you tried making up your own email with the event file attached, rather than than trying to send it via WinQuake? I am an AOL subscriber and have no problems sending that way. About a month ago, I experienced difficulties, but Larry found and fixed the problem. I have never attempted to send files from WinQuake itself.

  You cannot send more than one file at a time!!!  AOL always makes a ZIP of multiple attachments, and seismicnet's server does not accept ZIP files.

Regards,

Bob McClure
Locust Valley, NY, USA
40.882N  73.582W

__________________________________________________
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http://mail.yahoo.com Subject: Re: Re: earth tide tables From: "Cynthia" cynthia@......... Date: Mon, 4 Jul 2005 21:27:22 -0700 Hi Tom, Thanks kindly for your information. I was desperately searching the web that day trying to find what I needed. I finally found it on a Navy military site. (the tables that I needed) As a result, I correctly forcast the recent seismic activity. I had forcast them four months prior as did I forcast the December quake in the Indian Ocean. I have the time right (within 48 hours) 80 percent of the time, but I haven't been so good with the exact location. Tides are only about 1/40th of the equation, though, helping me with the location aspect of my formulas. I just didn't have the scientific background and don't live near libraries or adequate universities. Once I saw that I was within days, I had to get info quickly. Thanks for your big help. Feel free to keep me posted on any interesting upcoming events in your field. I'd truly love to hear about them, as our rise of activity (if I'm correct) is on the upswing over the next two years. It's interesting how sciences are really linked together when you look at the big picture. Cynthia in Oregon ----- Original Message ----- From: "Tom Schmitt" To: Sent: Sunday, June 26, 2005 10:34 AM Subject: RE: earth tide tables > I think that if you go to a basic geophysics book the sections on > gravimetery will have some formulas for the attraction of the moon and > sun as a function of latitude, year, time of day etc. One has to > correct for those when doing a gravity survey. The second order > effects are harder to get and very, very small. > > Absolute gravity measurements used to be made with pendulums. I do not > know how they do them now. I think they had to stay on station a long > time, like longer than the variation due to sun moon interactions, > however a good geophysics or geodesy book will have that in it also. > > Tom Schmitt > > -----Original Message----- > From: psn-l-request@.............. [mailto:psn-l-request@............... > On Behalf Of BOB BARNS > Sent: Friday, June 24, 2005 8:06 PM > To: psn mail > Subject: earth tide tables > > Hi gang, > > A friend has several high precision pendulum clocks (and has built 2 > others). > He asked me to inquire of this list about where to get tables of > earth tide data so that he can compare changes in the local value of g > to daily variations of period which he sees in his clocks. > > Bob > > __________________________________________________________ > > 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: Winquake suggestion From: Larry Conklin lconklin@............ Date: Wed, 06 Jul 2005 19:37:17 -0400 I often obtain event records that contain well defined features that I assume are the arrivals of phases other than the P or S arrivals, but I am not knowledgeable enough to be able to determine what path they may represent. It would be nice to have the option of turning on a "what's this" marker. Once the P/S picks are set, you would place the marker on the feature of interest, and Winquake would return a report that identifies the path that the feature represents, if any. Larry Conklin Liverpool, NY __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Winquake suggestion From: Larry Cochrane lcochrane@.............. Date: Thu, 07 Jul 2005 13:58:05 -0700 Hi Larry, Yes, this would be a nice feature. I'll add it to the "to do" list. I don't have time right now to work on WinQuake, so it will be a while before I can work on any new features in the program. Regards, Larry Cochrane Redwood City, PSN Larry Conklin wrote: > I often obtain event records that contain well defined features that I > assume are the arrivals of phases other than the P or S arrivals, but I > am not knowledgeable enough to be able to determine what path they may > represent. It would be nice to have the option of turning on a "what's > this" marker. Once the P/S picks are set, you would place the marker on > the feature of interest, and Winquake would return a report that > identifies the path that the feature represents, if any. > > Larry Conklin > Liverpool, NY > __________________________________________________________ > > 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: I am looking for geophones From: Mike Speed mike8s2@......... Date: Tue, 12 Jul 2005 12:54:24 -0700 (PDT) I have seen the geophones on: http://www.seismicnet.com/geophone/index.html I was wondering what other people have. I am looking for something about 25mm in diameter and 33mm in height. Pluses-or-minuses to those dimensions are just fine. If you have one or more you can part with, please let me know and provide details - how much for the device and approximately how much for shipping to Idaho. Thanks! Greg __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: I am looking for geophones From: "Ted Urbancic" urbancic@...... Date: Tue, 12 Jul 2005 20:42:01 +0000 GMT Great! I'll make arrangements. Ted -----Original Message----- From: Mike Speed Date: Tue, 12 Jul 2005 12:54:24 To:PSN Mailing List Subject: I am looking for geophones I have seen the geophones on: http://www.seismicnet.com/geophone/index.html I was wondering what other people have. I am looking for something about 25mm in diameter and 33mm in height. Pluses-or-minuses to those dimensions are just fine. If you have one or more you can part with, please let me know and provide details - how much for the device and approximately how much for shipping to Idaho. Thanks! Greg __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Dr. Ted Urbancic Director Engineering Seismology Group 1 Hyperion Court Kingston, ON K7K 7G3 O 613-548-8287 x225 C 613-539-3935 urbancic@...... www.esg-solutions.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: I am looking for geophones From: Mike Speed mike8s2@......... Date: Tue, 12 Jul 2005 20:39:32 -0700 (PDT) > Great! I'll make arrangements. > Ted Thank you! Greg __________________________________ Yahoo! Mail for Mobile Take Yahoo! Mail with you! Check email on your mobile phone. http://mobile.yahoo.com/learn/mail __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Modified sound card and datalogging and geophones From: Mike Speed mike8s2@......... Date: Mon, 18 Jul 2005 11:30:54 -0700 (PDT) I installed some larger-capacitance-value coupling capacitors on my 24-bit sound card so I could resolve lower frequencies. What is a good datalogging app to use with this? Also, I put out a request for geophones and got one response and never heard anything back. I am looking for geophones - tell me about what you have - dimensions - frequency, etc., and how much you want for them. Thanks, Greg __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: Mauro Mariotti mariotti@......... Date: Mon, 18 Jul 2005 17:41:55 +0200 Hi Greg, I doubt your a/d board will be capable to record low frequencies. Usually audio board has a high-pass filter at about 10Hz. This cut out all low frequency needed for earthquake recording. If you put a large capacitor inseries to the input this can only decrease the low frequency response. The only way you may have in recovering low frequencies is to use a digital inverse filter and use Lehman sensors instead of geophones. This because horizontal long period sensors (like lehman) are very sensitive to the low frequencies and give a lot of signal that sometime need to be cut-out with HP filters. Geophones has poor performances at low frequencies so they are absolutely not adequate for a standard audio board. Some expensive audio board has a hardware register to setup the frequency of the internal HP filter and could be used. You should refer to the manufacturer datasheet and see what you can do with your board. Regards mauro At 20:30 18/07/2005, you wrote: >I installed some larger-capacitance-value coupling >capacitors on my 24-bit sound card so I could resolve >lower frequencies. What is a good datalogging app to >use with this? > >Also, I put out a request for geophones and got one >response and never heard anything back. I am looking >for geophones - tell me about what you have - >dimensions - frequency, etc., and how much you want >for them. > >Thanks, > >Greg > >__________________________________________________ >Do You Yahoo!? >Tired of spam? Yahoo! Mail has the best spam protection around >http://mail.yahoo.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: Modified sound card and datalogging and geophones From: "Doug Crice" dcrice@............ Date: Mon, 18 Jul 2005 11:53:51 -0700 Greg, There was so much traffic on geophones that I thought you got an answer. = The best choice and the best price are those 4.5 Hz triaxial phones that = Larry has for sale. You can pull the sensors out of the case if you want just = the elements. See http://www.seismicnet.com/geophone/index.html If for some reason you want new geophones, see http://www.geospacelp.com/ http://www.sercel.com/en/Products/Sensors/Geophones.php http://www.i-o.com/Products/Product_Datasheets/ Used ones are also available from http://www.rtclark.com/ Bottom line, buy Larry's. Doug Crice http://www.geostuff.com Wireless Seismic http://www.wirelessSeismic.com 12996 Somerset Drive phone 1-530-274-4445 Grass Valley, CA 95945 USA fax 1-530-274-4446 =20 -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... = On Behalf Of Mike Speed Sent: Monday, July 18, 2005 11:31 AM To: PSN Mailing List Subject: Modified sound card and datalogging and geophones I installed some larger-capacitance-value coupling capacitors on my 24-bit sound card so I could resolve lower frequencies. What is a good datalogging app to use with this? Also, I put out a request for geophones and got one response and never heard anything back. I am looking for geophones - tell me about what you have - dimensions - frequency, etc., and how much you want for them. Thanks, Greg __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around=20 http://mail.yahoo.com=20 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: sound card datalogging From: Mike Speed mike8s2@......... Date: Mon, 18 Jul 2005 21:29:58 -0700 (PDT) Okay - forget the low frequency response of my sound card is poor. *Is there any good datalogging software for a sound card?* __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: sound card datalogging From: Gordon Couger gcouger@.......... Date: Tue, 19 Jul 2005 02:15:02 -0500 Mike, You should be able to over come the low frequency problems of sound cards by putting a mixer in the front of the final amplifier for the sound card uses a local oscillator that was right a the top of the sound card response and put the image beyond the range of the sound card. The signals will be reversed but fixing that with computer that run at today speed is no problem. Or you can put the local oscillator above the low end roll of the response of the sound card and digitally shave off the lower sides band with digital filters. Mixers like the NE 602 and it's replacement work from dc to 1 gHz. I strongly recommend Phillips mixer chips they come out of the box wanting to work. Gordon Mike Speed wrote: > Okay - forget the low frequency response of my sound > card is poor. *Is there any good datalogging software > for a sound card?* __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: "Geoff" gmvoeth@........... Date: Tue, 19 Jul 2005 07:23:44 -0700 Sorry, not sure why i received this letter from you. The subject matter is interesting though. I have found a prarie Digital A/D converter model 40-12 connected through COM1 DB25 or DB9 connector the best way to receive seismic signals but it requires some complex programming to make it work. It is not cheap also. It would be so nice to use the sound card so long as it will go to DC but if it does not then you need to use frequency translation of some type to make it work for you. Making for a more complex and expoensive circuyit to deal with. It just seems best to either build your own A/D Converter or to put oyt about $200 for one already built that you can program yourself. Your email came to me through the junk folder so it was screened out as spam. Sincerely, gmvoeth ----- Original Message ----- From: "Mike Speed" To: "PSN Mailing List" Sent: Monday, July 18, 2005 11:30 AM Subject: Modified sound card and datalogging and geophones >I installed some larger-capacitance-value coupling > capacitors on my 24-bit sound card so I could resolve > lower frequencies. What is a good datalogging app to > use with this? > > Also, I put out a request for geophones and got one > response and never heard anything back. I am looking > for geophones - tell me about what you have - > dimensions - frequency, etc., and how much you want > for them. > > Thanks, > > Greg > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.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: Modified sound card and datalogging and geophones From: ian ian@........... Date: Tue, 19 Jul 2005 15:48:04 +0100 hold the phone, as they say. If the budget has suddenly gone up from $0 then have a look at this: http://sine.ni.com/nips/cds/view/p/lang/en/nid/14604 This is a USB DAQ from National Instruments. It comes with the student (you may need an academic address for that?) version of labview and data loging software... It's around $150. Ian Geoff wrote: > Sorry, not sure why i received this letter from you. > The subject matter is interesting though. > I have found a prarie Digital A/D converter > model 40-12 connected through COM1 DB25 or DB9 > connector the best way to receive seismic signals > but it requires some complex programming to > make it work. > It is not cheap also. > It would be so nice to use the sound card so long > as it will go to DC but if it does not then > you need to use frequency translation of some type > to make it work for you. Making for a more complex > and expoensive circuyit to deal with. It just seems best to either > build your own > A/D Converter or to put oyt about $200 for one > already built that you can program yourself. > > Your email came to me through the junk folder so it was > screened out as spam. > > Sincerely, > gmvoeth > > ----- Original Message ----- From: "Mike Speed" > To: "PSN Mailing List" > Sent: Monday, July 18, 2005 11:30 AM > Subject: Modified sound card and datalogging and geophones > > >> I installed some larger-capacitance-value coupling >> capacitors on my 24-bit sound card so I could resolve >> lower frequencies. What is a good datalogging app to >> use with this? >> >> Also, I put out a request for geophones and got one >> response and never heard anything back. I am looking >> for geophones - tell me about what you have - >> dimensions - frequency, etc., and how much you want >> for them. >> >> Thanks, >> >> Greg >> >> __________________________________________________ >> Do You Yahoo!? >> Tired of spam? Yahoo! Mail has the best spam protection around >> http://mail.yahoo.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) > > 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: Modified sound card and datalogging and geophones From: "Geoff" gmvoeth@........... Date: Tue, 19 Jul 2005 08:42:12 -0700 The site you pointed me to was very interesting but I use an older laptop that has no USB connection for the transfer of data I must use COM1 or LPT1 ports only. I once built my own 8bit converter that worked flawlessly with timing and control from the computer using the parallel bidirectional port. Now I am using the prarie digital model 12-40 which seems to work ok if I only use the upper 9 bits of resolution. My sample rates are dictated by the computer tic counter which runs about 65536/3600 samples per second. I limit my frequencies to below 9 Hz prior to conversion. You folks seem to be emailing me about something I posted ages ago which surprises me. Sincerely, gmvoeth __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: "David Saum" DSaum@............ Date: Tue, 19 Jul 2005 13:03:22 -0400 > From: Mike Speed > Date: Mon, 18 Jul 2005 21:29:58 -0700 (PDT) > > Okay - forget the low frequency response of my sound > card is poor. *Is there any good datalogging software > for a sound card?* For data display and logging with a sound card, I like the free "Spectrum Lab" software http://www.qsl.net/dl4yhf/spectra1.html You may want to get a low noise 24 bit sound card with hardware sampling up to 96khz. I have had good luck with the Audigy 2 ZS. I found one for around $60 on http://www.pricewatch.com Ciao, Dave http://www.infiltec.com/seismo http://www.infiltec.com/SID-GRB@home __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: ChrisAtUpw@....... Date: Tue, 19 Jul 2005 19:50:39 EDT In a message dated 18/07/2005 19:31:08 GMT Daylight Time, mike8s2@......... writes: installed some larger-capacitance-value coupling capacitors on my 24-bit sound card so I could resolve lower frequencies. What is a good datalogging app to use with this? Hi Greg, I suggest that you look at Larry's website at _http://psn.quake.net/_ (http://psn.quake.net/) and read some of the articles. Look at other websites on _http://psn.quake.net/dave/map.htm_ (http://psn.quake.net/dave/map.htm) A soundcard by itself has a frequency range of about 10 Hz to 24 KHz and it is basically an AC only device. The 10 Hz lower frequency is limited by the input C + R circuit. The standard PC drivers set the sample rate from 8,000 to 48,000 sps. Using this, you end up with simply massive files on a daily basis and no quick way of monitoring them. I haven't seen an application which enables you to use the soundcard ADC at really low sample rates, say 20 / sec and return them to a file. Assuming that you are in the States, you can buy a $25 10 bit ADC from Dataq, but it is usual to use 12 to 16 bit ADCs. Following on a geophone, you will need a low noise amplifier and a filter. See _http://users.viawest.net/~aloomis/seismom.htm_ (http://users.viawest.net/~aloomis/seismom.htm) or _http://www.jclahr.com/science/psn/amp_filt/index.html_ (http://www.jclahr.com/science/psn/amp_filt/index.html) It is usual to limit amateur seismic sensors to frequencies of less than 10 Hz. This cuts out most of the urban traffic and environmental noise, which is of no interest to most of us and may swamp everything else above 20 Hz. You also need a timing system which is good to better than 1 sec. Unfortunately, most computers are fitted with something called a 'software clock', which can vary by minutes per day. The first seismic P waves travel at maybe 10 km / sec, so a 1 minute error would give a location error of ~380 miles. This really is useless for seismic work and why you need a dedicated data recording program which takes this into account. The P and S waves are of most interest to us, since they enable you to determine the distance of the quake from your station. Long distance P waves are at about 1 Hz and S waves are at about 0.5 Hz, but nearby quakes have higher frequency components. The 'cheap' 4.5 Hz geophones can be extended down to about 0.5 Hz with a special amplifier, but they will also pick up local and near regional quakes on their own. It is also possible to make a really cheap vibration detector / seismometer using piezo disks and added weights. I use one from about 0.25 Hz to 10 Hz, but I need a FET input opamp and good screened cable to do this. Do 'read up' about earthquakes and seismometers before you start. There is a lot to learn! To go beyond this very basic advice, I would need to know where you are located, your knowledge of electronics, what tools / constructional skills you have and how much you are prepared to spend. I am not being inquisitive, merely practical. Commercial seismometer systems may cost several 10's of thousands of $, but amateur systems may be made from a few $100 upwards. You can exchange construction time + skills for ready made equipment, but the effort may be considerable. The real art lies in not making too many mistakes..... I hope that this hslps... Regards, Chris Chapman

In a message dated 18/07/2005 19:31:08 GMT Daylight Time, mike8s2@yahoo= ..com=20 writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20 size=3D2>installed some larger-capacitance-value coupling capacitors on my= =20 24-bit sound card so I could resolve lower frequencies.  What is a go= od=20 datalogging app to
use with this?
Hi Greg,
 
    I suggest that you look at Larry's website at <= A=20 href=3D"http://psn.quake.net/">http://psn.quake.net/ and read some=20= of the=20 articles. Look at other websites on http://psn.quake.net/dave/map.htm=
    A soundcard by itself has a frequency range of=20 about 10 Hz to 24 KHz and it is basically an AC only device. The 10=20 Hz lower frequency is limited by the input C + R circuit. The= =20 standard PC drivers set the sample rate from 8,000 to 48,000 sps. Using=20 this, you end up with simply massive files on a daily basis and no quick way= of=20 monitoring them. I haven't seen an application which enables you to use the=20 soundcard ADC at really low sample rates, say 20 / sec and return them to a=20 file.
    Assuming that you are in the States, you can bu= y a=20 $25 10 bit ADC from Dataq, but it is usual to use 12 to 16 bit ADCs. Followi= ng=20 on a geophone, you will need a low noise amplifier and a filter. See http://users.viawest.= net/~aloomis/seismom.htm or=20 http://www.jc= lahr.com/science/psn/amp_filt/index.html
    It is usual to limit amateur seismic senso= rs=20 to frequencies of less than 10 Hz. This cuts out most of the urban traffic a= nd=20 environmental noise, which is of no interest to most of us and may swamp=20 everything else above 20 Hz.  
    You also need a timing system which is good to=20 better than 1 sec. Unfortunately, most computers are fitted with something=20 called a 'software clock', which can vary by minutes per day. The first=20 seismic P waves travel at maybe 10 km / sec, so a 1 minute error would=20= give=20 a location error of ~380 miles. This really is useless for seismic work and=20= why=20 you need a dedicated data recording program which takes this into account.=20
    The P and S waves are of most interest to us, s= ince=20 they enable you to determine the distance of the quake from your station. Lo= ng=20 distance P waves are at about 1 Hz and S waves are at about 0.5 Hz, but near= by=20 quakes have higher frequency components.
    The 'cheap' 4.5 Hz geophones can be extend= ed=20 down to about 0.5 Hz with a special amplifier, but they will also pick up lo= cal=20 and near regional quakes on their own.
    It is also possible to make a really cheap= =20 vibration detector / seismometer using piezo disks and added weights. I= use=20 one from about 0.25 Hz to 10 Hz, but I need a FET input opamp and good=20 screened cable to do this.    
    Do 'read up' about earthquakes and=20 seismometers before you start. There is a lot to learn!
    To go beyond this very basic advice, I would ne= ed=20 to know where you are located, your knowledge of electronics, what tools /=20 constructional skills you have and how much you are prepared to sp= end.=20 I am not being inquisitive, merely practical. Commercial seismometer systems= may=20 cost several 10's of thousands of $, but amateur systems may be made from a=20= few=20 $100 upwards. You can exchange construction time + skills for ready made=20 equipment, but the effort may be considerable. The real art lies in not maki= ng=20 too many mistakes.....
 
    I hope that this hslps...
 
    Regards,
 
    Chris Chapman
 
Subject: [Fwd: hurricane Dennis study] From: Larry Cochrane lcochrane@.............. Date: Tue, 19 Jul 2005 17:28:48 -0700 Hi Everyone, I received the following from Dr. Randall Peters. With his permission I am forwarding it to the list. Regards, Larry Cochrane Redwood City, PSN -------- Original Message -------- Subject: hurricane Dennis study Date: Sun, 17 Jul 2005 12:11:05 -0400 From: Randall Peters To: lcochrane@.............. Hi Larry. I have posted a paper to our server here at Mercer University Physics that might be interesting to the amateur seismology community. It is titled, "Correlation measurements of atmospheric pressure variations and seismicity during hurricane Dennis", online at http://physics.mercer.edu/hpage/corr.html The seismometer used for this study is an old Sprengnether that was once part of the WWSSN. It was a gift from emeritus Prof. Deskin Shurbet of Texas Tech University (my academic home before coming to Mercer). I've noticed some discussions on psn concerning the viability of old surplused instruments like this, which use the LaCoste zero-length spring. My opinion is that they can be made to function very well indeed, with a modernized sensor. In my case, the instrument works with an array form of the SDC sensor. As opposed to the gap-varying mode of conventional commercial seismometers used by professionals, the area-varying sensor has many advantages. For example, I am presently operating without any force feedback, although for the previous hurricane Charley study http://arxiv.org/html/physics/0506162 I used the original coil/magnet (sensor/damper) subsystem as an actuator to provide 'weak' force feedback. The feedback involved only a long-period opamp integrator. The use of total force-balance (PID, or proportional integral derivative network) is a cause for serious performance degradation at low frequencies. I would like to encourage the amateur community to get involved with me in studying the mHz frequency regime (where the earth hums), by opening up instrument performance at low frequencies. To do so requires a paradigm shift, and I suspect that the amateurs are more open to this than are the professionals. One of the first things necessary is to depart (heresy of heresies) from insisting on velocity detection. To take the derivative is to ruin low frequency sensitivity, since as every student that I teach knows-- it pulls out an 'omega' by the chain rule of calculus--causing a 20 dB/decade falloff below the lower frequency cutoff. If you look at the unfiltered earthquake record in the above referenced paper concerning hurricane Dennis, you will see that the output from the sensor is displacement, rather than velocity. For anybody insisting on 'doing business as usual', for better identifying P and S body waves; then it is a simple matter to do post-processor numerical differentiation of the filtered waveform. Incidently, for those who may be interested, I've posted a paper that shows how to do filtering with excel: http://physics.mercer.edu/hpage/filter/gauss.html The beauty of better low frequency performance is that you can study the long-period Rayleigh and Love waves also with the same instrument. And although many are suspicious of my claims, I am confident that my Sprengnether is picking up eigenmodes (free oscillations of the earth). Many of my own successes have been the indirect consequence of the amateur community. For example, were it not for John Lahr and his interaction with a broad group of individuals to include the amateurs, I would not have learned of the Dataq software that I have found to be so powerful. Also, Chris Chapman, who contributes regularly to psn discussions is a friend whose expertise I admire and whose suggestions (and corrections) directed toward various parts of my work have been greatly appreciated. Additionally, Allan Coleman has just built an interesting broadband vertical seismometer using a gap-varying form of my SDC sensor with a Willmore spring. http://physics.mercer.edu/petepag/mkxx.pdf Bottom line--don't ever underestimate the significance of what you've about! I have been reluctant to get involved with psn before now for reasons expressed in one of Chris' writings sometime back. He noted that academics like myself get caught up so thoroughly in bureaucratic issues that they barely have time to do the research that is expected of them. In the event that I get more feedback (emails) from this communication than I can completely respond to personally , please don't be offended. I despise the treatment of 'kill by silence' that has been directed at me because of my unconventional ideas. Perhaps folks will be interested to know about the 'affordable earthquake detector' that I am trying with some partners to bring to market. There was an article about this in Popular Science (April issue, page 104). I have developed a truly inexpensive autozeroeing electronics package to work with the SDC sensors. Used it, in fact, to operate the pressure sensor in the Dennis study. The board has only three chips, each of which is less than $1 apiece. Doubt that this scheme, which works with diodes, is able to do the low frequency measurements I've mentioned; but it certainly would be an interesting possibility for a bare-bones vertical instrument with outstanding performance. Maybe there are some individuals who would like to try and build something using this electronics with my compound vertical seismometer, described at http://www.iris.edu/stations/seisWorkshop04/PDF/CompoundVerticalSeismometer.pdf Would like to finally mention that Analog Devices has just marketed a 24-bit ADC that should work with my sensor directly and which sells for less than $10. http://www.analog.com/en/prod/0,2877,AD7745,00.html (Tim Long at Georgia Tech, just-retired seismologist alerted me to this chip; Tim is interested in putting cheap but functional instruments in the hands of science teachers; a great idea for which I hope we all can help!) Only problem is that this chip requires a microcontroller to work. Anybody with dsp experience interested in developing the necessary software tools to make this happen with a cheap microcontroller? I can envision something that might make the professionals take notice even if the price were a hundred times greater!! Keep up the good work, Randall Peters, PhD Professor and Chairman Dept. of Physics Mercer University Macon, Georgia 31207 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: [Fwd: hurricane Dennis study] From: "Kareem at HeyJooJoo" system98765@............. Date: Tue, 19 Jul 2005 17:49:22 -0700 Any comments? -----Original Message----- From: Larry Cochrane [mailto:lcochrane@............... Sent: Tuesday, July 19, 2005 5:29 PM To: psn-l@.............. Subject: [Fwd: hurricane Dennis study] Hi Everyone, I received the following from Dr. Randall Peters. With his permission I am forwarding it to the list. Regards, Larry Cochrane Redwood City, PSN -------- Original Message -------- Subject: hurricane Dennis study Date: Sun, 17 Jul 2005 12:11:05 -0400 From: Randall Peters To: lcochrane@.............. Hi Larry. I have posted a paper to our server here at Mercer University Physics that might be interesting to the amateur seismology community. It is titled, "Correlation measurements of atmospheric pressure variations and seismicity during hurricane Dennis", online at http://physics.mercer.edu/hpage/corr.html The seismometer used for this study is an old Sprengnether that was once part of the WWSSN. It was a gift from emeritus Prof. Deskin Shurbet of Texas Tech University (my academic home before coming to Mercer). I've noticed some discussions on psn concerning the viability of old surplused instruments like this, which use the LaCoste zero-length spring. My opinion is that they can be made to function very well indeed, with a modernized sensor. In my case, the instrument works with an array form of the SDC sensor. As opposed to the gap-varying mode of conventional commercial seismometers used by professionals, the area-varying sensor has many advantages. For example, I am presently operating without any force feedback, although for the previous hurricane Charley study http://arxiv.org/html/physics/0506162 I used the original coil/magnet (sensor/damper) subsystem as an actuator to provide 'weak' force feedback. The feedback involved only a long-period opamp integrator. The use of total force-balance (PID, or proportional integral derivative network) is a cause for serious performance degradation at low frequencies. I would like to encourage the amateur community to get involved with me in studying the mHz frequency regime (where the earth hums), by opening up instrument performance at low frequencies. To do so requires a paradigm shift, and I suspect that the amateurs are more open to this than are the professionals. One of the first things necessary is to depart (heresy of heresies) from insisting on velocity detection. To take the derivative is to ruin low frequency sensitivity, since as every student that I teach knows-- it pulls out an 'omega' by the chain rule of calculus--causing a 20 dB/decade falloff below the lower frequency cutoff. If you look at the unfiltered earthquake record in the above referenced paper concerning hurricane Dennis, you will see that the output from the sensor is displacement, rather than velocity. For anybody insisting on 'doing business as usual', for better identifying P and S body waves; then it is a simple matter to do post-processor numerical differentiation of the filtered waveform. Incidently, for those who may be interested, I've posted a paper that shows how to do filtering with excel: http://physics.mercer.edu/hpage/filter/gauss.html The beauty of better low frequency performance is that you can study the long-period Rayleigh and Love waves also with the same instrument. And although many are suspicious of my claims, I am confident that my Sprengnether is picking up eigenmodes (free oscillations of the earth). Many of my own successes have been the indirect consequence of the amateur community. For example, were it not for John Lahr and his interaction with a broad group of individuals to include the amateurs, I would not have learned of the Dataq software that I have found to be so powerful. Also, Chris Chapman, who contributes regularly to psn discussions is a friend whose expertise I admire and whose suggestions (and corrections) directed toward various parts of my work have been greatly appreciated. Additionally, Allan Coleman has just built an interesting broadband vertical seismometer using a gap-varying form of my SDC sensor with a Willmore spring. http://physics.mercer.edu/petepag/mkxx.pdf Bottom line--don't ever underestimate the significance of what you've about! I have been reluctant to get involved with psn before now for reasons expressed in one of Chris' writings sometime back. He noted that academics like myself get caught up so thoroughly in bureaucratic issues that they barely have time to do the research that is expected of them. In the event that I get more feedback (emails) from this communication than I can completely respond to personally , please don't be offended. I despise the treatment of 'kill by silence' that has been directed at me because of my unconventional ideas. Perhaps folks will be interested to know about the 'affordable earthquake detector' that I am trying with some partners to bring to market. There was an article about this in Popular Science (April issue, page 104). I have developed a truly inexpensive autozeroeing electronics package to work with the SDC sensors. Used it, in fact, to operate the pressure sensor in the Dennis study. The board has only three chips, each of which is less than $1 apiece. Doubt that this scheme, which works with diodes, is able to do the low frequency measurements I've mentioned; but it certainly would be an interesting possibility for a bare-bones vertical instrument with outstanding performance. Maybe there are some individuals who would like to try and build something using this electronics with my compound vertical seismometer, described at http://www.iris.edu/stations/seisWorkshop04/PDF/CompoundVerticalSeismometer. pdf Would like to finally mention that Analog Devices has just marketed a 24-bit ADC that should work with my sensor directly and which sells for less than $10. http://www.analog.com/en/prod/0,2877,AD7745,00.html (Tim Long at Georgia Tech, just-retired seismologist alerted me to this chip; Tim is interested in putting cheap but functional instruments in the hands of science teachers; a great idea for which I hope we all can help!) Only problem is that this chip requires a microcontroller to work. Anybody with dsp experience interested in developing the necessary software tools to make this happen with a cheap microcontroller? I can envision something that might make the professionals take notice even if the price were a hundred times greater!! Keep up the good work, Randall Peters, PhD Professor and Chairman Dept. of Physics Mercer University Macon, Georgia 31207 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: Michael Chang pya_cha@.................. Date: Tue, 19 Jul 2005 23:03:00 -0400 It appears sound cards can be easily modified to be DC responding through a front-end amplifier with an appropriate DC offset, and of course, removal of the coupling capacitor: http://www.qsl.net/om3cph/sb/dcwithsb.htm Michael http://photo.net/photodb/member-photos?user_id=423056&include=all At 07:50 PM 19/07/2005, you wrote: >In a message dated 18/07/2005 19:31:08 GMT Daylight Time, >mike8s2@......... writes: >installed some larger-capacitance-value coupling capacitors on my 24-bit >sound card so I could resolve lower frequencies. What is a good >datalogging app to >use with this? It appears sound cards can be easily modified to be DC responding through a front-end amplifier with an appropriate DC offset, and of course, removal of the coupling capacitor:
http://www.qsl.net/om3cph/sb/dcwithsb.htm

Michael
http://photo.net/photodb/member-photos?user_id=423056&include=all

At 07:50 PM 19/07/2005, you wrote:
In a message dated 18/07/2005 19:31:08 GMT Daylight Time, mike8s2@......... writes:
installed some larger-capacitance-value coupling capacitors on my 24-bit sound card so I could resolve lower frequencies.  What is a good datalogging app to
use with this?
Subject: Re: Modified sound card and datalogging and geophones From: Gordon Couger gcouger@.......... Date: Wed, 20 Jul 2005 00:37:54 -0500 Hi Chris, Have you considered using a mixer with local oscillator frequency that puts the unwanted image above the range of the sound card. It inverts the spectrum but that's no problem with computers as fast as we have. Gordon Couger Stillwater, OK www.couger.com/gcouger ChrisAtUpw@....... wrote: > In a message dated 18/07/2005 19:31:08 GMT Daylight Time, > mike8s2@......... writes: > > installed some larger-capacitance-value coupling capacitors on my > 24-bit sound card so I could resolve lower frequencies. What is a > good datalogging app to > use with this? > > Hi Greg, > > I suggest that you look at Larry's website at > http://psn.quake.net/ and read some of the articles. Look at other > websites on http://psn.quake.net/dave/map.htm > A soundcard by itself has a frequency range of about 10 Hz to 24 KHz > and it is basically an AC only device. The 10 Hz lower frequency is > limited by the input C + R circuit. The standard PC drivers set the > sample rate from 8,000 to 48,000 sps. Using this, you end up with simply > massive files on a daily basis and no quick way of monitoring them. I > haven't seen an application which enables you to use the soundcard ADC > at really low sample rates, say 20 / sec and return them to a file. > Assuming that you are in the States, you can buy a $25 10 bit ADC > from Dataq, but it is usual to use 12 to 16 bit ADCs. Following on a > geophone, you will need a low noise amplifier and a filter. See > http://users.viawest.net/~aloomis/seismom.htm or > http://www.jclahr.com/science/psn/amp_filt/index.html > It is usual to limit amateur seismic sensors to frequencies of less > than 10 Hz. This cuts out most of the urban traffic and environmental > noise, which is of no interest to most of us and may swamp everything > else above 20 Hz. > You also need a timing system which is good to better than 1 sec. > Unfortunately, most computers are fitted with something called a > 'software clock', which can vary by minutes per day. The first seismic P > waves travel at maybe 10 km / sec, so a 1 minute error would give a > location error of ~380 miles. This really is useless for seismic work > and why you need a dedicated data recording program which takes this > into account. > The P and S waves are of most interest to us, since they enable you > to determine the distance of the quake from your station. Long distance > P waves are at about 1 Hz and S waves are at about 0.5 Hz, but nearby > quakes have higher frequency components. > The 'cheap' 4.5 Hz geophones can be extended down to about 0.5 Hz > with a special amplifier, but they will also pick up local and near > regional quakes on their own. > It is also possible to make a really cheap vibration detector / > seismometer using piezo disks and added weights. I use one from about > 0.25 Hz to 10 Hz, but I need a FET input opamp and good screened cable > to do this. > *Do 'read up' about earthquakes and seismometers before you start. > There is a lot to learn!* > To go beyond this very basic advice, I would need to know where you > are located, your knowledge of electronics, what tools / constructional > skills you have and how much you are prepared to spend. I am not being > inquisitive, merely practical. Commercial seismometer systems may cost > several 10's of thousands of $, but amateur systems may be made from a > few $100 upwards. You can exchange construction time + skills for ready > made equipment, but the effort may be considerable. The real art lies in > not making too many mistakes..... > > I hope that this hslps... > > Regards, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: ChrisAtUpw@....... Date: Wed, 20 Jul 2005 07:43:19 EDT In a message dated 20/07/2005, gcouger@.......... writes: Hi Chris, Have you considered using a mixer with local oscillator frequency that puts the unwanted image above the range of the sound card. It inverts the spectrum but that's no problem with computers as fast as we have. Gordon Couger Stillwater, OK www.couger.com/gcouger Hi Gordon, No I haven't. You get into sharp cut filters for the end of the band, which tends to covert the problem into a headache. I did not mention the simple removal of the input capacitor and fitting an input opamp, for the same reason. You are still left with the 8,000 sps minimum, which generates ~2.7 G bytes / day / channel. Until we are able to control the sample rate as desired, to say 20 sps, the method is unsatisfactory for long term recording. It must be possible in principle, but I suspect that it is hidden in the commercial software. The way that I have used small disk stereo audio recorders for data recording is to convert the analogue signal into a variable frequency sine wave and record that. The only problem is that while you can get very fast V->F changes, you can't easily recover fast F->V changes, so you need low bandwidth. You can add maybe 3 different frequency ranges per audio channel and sort the output with bandpass filters, but it is complicated. Regards, Chris Chapman
In a message dated 20/07/2005, gcouger@.......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Hi=20 Chris,

Have you considered using a mixer with local oscillator=20
frequency that puts the unwanted image above the range of the
soun= d=20 card.

It inverts the spectrum but that's no problem with computers=20= as=20
fast as we have.

Gordon Couger
Stillwater,=20 OK
www.couger.com/gcouger
Hi Gordon,
 
    No I haven't. You get into sharp cut filters fo= r=20 the end of the band, which tends to covert the problem into a headache. I di= d=20 not mention the simple removal of the input capacitor and fitting an input=20 opamp, for the same reason. You are still left with the 8,000 sps minimum, w= hich=20 generates ~2.7 G bytes / day / channel. Until we are able to control the sam= ple=20 rate as desired, to say 20 sps, the method is unsatisfactory for long term=20 recording. It must be possible in principle, but I suspect that it is=20 hidden in the commercial software.
    The way that I have used small disk stereo audi= o=20 recorders for data recording is to convert the analogue signal into a=20 variable frequency sine wave and record that. The only problem is that while= you=20 can get very fast V->F changes, you can't easily recover fast F->V=20 changes, so you need low bandwidth. You can add maybe 3 different frequency=20 ranges per audio channel and sort the output with bandpass filters, but= it=20 is complicated.
 
    Regards,
 
    Chris Chapman
Subject: Re: [Fwd: hurricane Dennis study] From: "James Hannon" jmhannon@......... Date: Wed, 20 Jul 105 14:39:40 CDT Wow. This makes my want to get back to building seismographs! Jim Hannon ---------- Original Message ---------------------------------- From: Larry Cochrane Reply-To: psn-l@.............. Date: Tue, 19 Jul 2005 17:28:48 -0700 >Hi Everyone, > >I received the following from Dr. Randall Peters. With his permission I am forwarding >it to the list. > >Regards, >Larry Cochrane >Redwood City, PSN > > -- Jim Hannon http://www.fmtcs.com/web/jmhannon/ 42,11.90N,91,39.26W WB0TXL -- __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: Gordon Couger gcouger@.......... Date: Wed, 20 Jul 2005 15:02:44 -0500 Chris, If you are recording Audio and use the mixer a high LO to invert the signal then at the end of the day play back the recording into a computer and use digital filters to pull out what you want and store it on CD ROM or DVD with software that has been developed in public domain, GNU and share ware. TAPR http://www.tapr.org/ is a good starting point. Recoding everything in real time then doing the signal processing one pass at a time is a great deal easier to do than doing it all in real time. Of course it must be automated and take less time to process than record. Gordon ChrisAtUpw@....... wrote: > In a message dated 20/07/2005, gcouger@.......... writes: > > Hi Chris, > > Have you considered using a mixer with local oscillator > frequency that puts the unwanted image above the range of the > sound card. > > It inverts the spectrum but that's no problem with computers as > fast as we have. > > Gordon Couger > Stillwater, OK > www.couger.com/gcouger > > Hi Gordon, > > No I haven't. You get into sharp cut filters for the end of the > band, which tends to covert the problem into a headache. I did not > mention the simple removal of the input capacitor and fitting an input > opamp, for the same reason. You are still left with the 8,000 sps > minimum, which generates ~2.7 G bytes / day / channel. Until we are able > to control the sample rate as desired, to say 20 sps, the method is > unsatisfactory for long term recording. It must be possible in > principle, but I suspect that it is hidden in the commercial software. > The way that I have used small disk stereo audio recorders for data > recording is to convert the analogue signal into a variable frequency > sine wave and record that. The only problem is that while you can get > very fast V->F changes, you can't easily recover fast F->V changes, so > you need low bandwidth. You can add maybe 3 different frequency > ranges per audio channel and sort the output with bandpass filters, but > it is complicated. > > Regards, > > Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: Gordon Couger gcouger@.......... Date: Wed, 20 Jul 2005 16:43:51 -0500 Chris, Out of sequence and possible not on subject but it has some thoughts on timing that are important. I must have come in the middle and don't understand your set up. I thought you were recording data to disk with a computer sound card. I am working on a sismomenter that records several sismometers at one time in the 0-50 HZ rang on the two channels of a sound card for imaging shallow aquifers looking for larger gravel to find better water well in a shallow aquifer along Red River between Oklahoma and Texas so I can afford to put in irrigation. I have probably imposed my project on yours without realizing it. A GPS will give you the best time stamp you could ask for some even have a 100 kHz clock as well a 1 second pulse that are linked to GPS clocks. They can be used to phase lock frequency sources to for super accurate osilators. If you are not interested in 1 to 20 Hz signals sound cards are pretty good tools. If you are really serious about low frequencies and accurate timing Windows poses a lot of problems. First Windows is an event driven operating system and there is no assurance when a program will run. The sound card gets around that but you have to put a chirp on the signal to synchronize it with time you can depend on the computer clock or the RS232 port. Having worked with embedded systems for the last 20 years I would choose a real time computer. There are real time versions of Linux but I think that's over kill for dataloging geophones. A GPS for a time base, a good a/d converter and fast microcontroler would be the way I would do it. I am working with a very fast board 60 MHz with 4 10 bit A/D channels Gordon ChrisAtUpw@....... wrote: > In a message dated 18/07/2005 19:31:08 GMT Daylight Time, > mike8s2@......... writes: > > installed some larger-capacitance-value coupling capacitors on my > 24-bit sound card so I could resolve lower frequencies. What is a > good datalogging app to > use with this? > > Hi Greg, > > I suggest that you look at Larry's website at > http://psn.quake.net/ and read some of the articles. Look at other > websites on http://psn.quake.net/dave/map.htm > A soundcard by itself has a frequency range of about 10 Hz to 24 KHz > and it is basically an AC only device. The 10 Hz lower frequency is > limited by the input C + R circuit. The standard PC drivers set the > sample rate from 8,000 to 48,000 sps. Using this, you end up with simply > massive files on a daily basis and no quick way of monitoring them. I > haven't seen an application which enables you to use the soundcard ADC > at really low sample rates, say 20 / sec and return them to a file. > Assuming that you are in the States, you can buy a $25 10 bit ADC > from Dataq, but it is usual to use 12 to 16 bit ADCs. Following on a > geophone, you will need a low noise amplifier and a filter. See > http://users.viawest.net/~aloomis/seismom.htm or > http://www.jclahr.com/science/psn/amp_filt/index.html > It is usual to limit amateur seismic sensors to frequencies of less > than 10 Hz. This cuts out most of the urban traffic and environmental > noise, which is of no interest to most of us and may swamp everything > else above 20 Hz. > You also need a timing system which is good to better than 1 sec. > Unfortunately, most computers are fitted with something called a > 'software clock', which can vary by minutes per day. The first seismic P > waves travel at maybe 10 km / sec, so a 1 minute error would give a > location error of ~380 miles. This really is useless for seismic work > and why you need a dedicated data recording program which takes this > into account. > The P and S waves are of most interest to us, since they enable you > to determine the distance of the quake from your station. Long distance > P waves are at about 1 Hz and S waves are at about 0.5 Hz, but nearby > quakes have higher frequency components. > The 'cheap' 4.5 Hz geophones can be extended down to about 0.5 Hz > with a special amplifier, but they will also pick up local and near > regional quakes on their own. > It is also possible to make a really cheap vibration detector / > seismometer using piezo disks and added weights. I use one from about > 0.25 Hz to 10 Hz, but I need a FET input opamp and good screened cable > to do this. > *Do 'read up' about earthquakes and seismometers before you start. > There is a lot to learn!* > To go beyond this very basic advice, I would need to know where you > are located, your knowledge of electronics, what tools / constructional > skills you have and how much you are prepared to spend. I am not being > inquisitive, merely practical. Commercial seismometer systems may cost > several 10's of thousands of $, but amateur systems may be made from a > few $100 upwards. You can exchange construction time + skills for ready > made equipment, but the effort may be considerable. The real art lies in > not making too many mistakes..... > > I hope that this hslps... > > Regards, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: ChrisAtUpw@....... Date: Wed, 20 Jul 2005 19:19:02 EDT In a message dated 20/07/2005, gcouger@.......... writes: If you are recording Audio and use the mixer Hi Gordon, I was using three V/F sine wave converters per channel and inputting this into the digitial recorder as a sum. The three channels had very different centre frequencies and did not overlap. Then I took the recorder output, passed it through three bandpass filters and into three PLL detectors, which gave voltage outputs. This was straight FM type recording, no computer involved at that stage, just a box of chips. I was actually recording instrument signals in a glider, so it had to be small and light - airspeed, lift and sink, altitude and a couple of other variables. I started out with a stereo tape recorder and graduated to digital stereo. Regards, Chris Chapman
In a message dated 20/07/2005, gcouger@.......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>If you=20 are recording Audio and use the mixer
Hi Gordon,
 
    I was using three V/F sine wave converters= per=20 channel and inputting this into the digitial recorder as a sum. The three=20 channels had very different centre frequencies and did not overlap.
    Then I took the recorder output, passed it thro= ugh=20 three bandpass filters and into three PLL detectors, which gave voltage=20 outputs.
    This was straight FM type recording, no compute= r=20 involved at that stage, just a box of chips. I was actually recording instru= ment=20 signals in a glider, so it had to be small and light - airspeed, lift and=20 sink, altitude and a couple of other variables. I started out with a st= ereo=20 tape recorder and graduated to digital stereo. 
 
    Regards,
 
    Chris Chapman
Subject: Re: Modified sound card and datalogging and geophones From: ChrisAtUpw@....... Date: Wed, 20 Jul 2005 21:41:22 EDT In a message dated 20/07/2005, gcouger@.......... writes: Chris, Out of sequence and possible not on subject but it has some thoughts on timing that are important. I must have come in the middle and don't understand your set up. I thought you were recording data to disk with a computer sound card. I am working on a sismomenter that records several sismometers at one time in the 0-50 HZ range on the two channels of a sound card for imaging shallow aquifers looking for larger gravel to find better water well in a shallow aquifer along Red River between Oklahoma and Texas so I can afford to put in irrigation. I have probably imposed my project on yours without realizing it. Hi Gordon, We were discussing sound cards and I was rejecting this as impractical for seismic purposes. The data files are massive and I haven't found a way of using the 24 bit soundcard ADC for 20 sps sampling. Chuck a bit of cash at it and get rid of the your problems? Larry sells a fairly good 8 channel serial board, which you can use with a GPS receiver. If you want to play, fine. If you want to work, get rid of problems that you do not need to have. Just what rate of water rise do you get along the Red river?? Even for marine waves, 20 sps is adequate and most geological systems will go to 100sps, some even more. >> A GPS will give you the best time stamp you could ask for some even have a 100 kHz clock as well a 1 second pulse that are linked to GPS clocks. They can be used to phase lock frequency sources to for super accurate osillators. I am NOT asking for the best system, just one that relatively inexpensive, low power and ADEQUATE for my purposes. I use VLF timing signals. You can get relatively inexpensive receiver boards with a ferrite aerial: or gut a radio clock. You get about 10 mS + the transit time. The only folks who need it more accurate monitor volcanoes of do reflection seismometry. I have been all along this road. I would be great if Larry would fit the software to decode WWVB directly, but he seems concentrate on GPS. GPS is power hungry and needs a clear line of sight to satellites; 60 KHz VLF radio is low power and can be used most anywere. I can use it where I can't get MW radio, even underground. Just keep it away from striplights, radio transmitters, TVs and computer monitors. I have used it underground near radio and TV transmitters - find a nice hole and bury it to screen it! It is no accident that submarine communications use the VLF range of frequencies. If you are not interested in 1 to 20 Hz signals sound cards are pretty good tools. If you are really serious about low frequencies and accurate timing Windows poses a lot of problems. 0 to 10 Hz is my range of interest. I want about +/-0.1 sec accuracy, 24 hrs / day. This is why I use an ADC which has it's own on board timing and correction. The data goes to the hard disk with a time stamp regardless of the rubbish timing on the operating system. First Windows is an event driven operating system and there is no assurance when a program will run. The sound card gets around that but you have to put a chirp on the signal to synchronize it with time you can depend on the computer clock or the RS232 port. Can you say that again please? I don't quite understand. Having worked with embedded systems for the last 20 years I would choose a real time computer. There are real time versions of Linux but I think that's over kill for dataloging geophones. You have the real and the software clocks on computer boards. You used to be able to get 4.194 MHz AT crystal clocks on computers, which could be made moderately reliable. All the boards that I have seen recently use 32 KHz crystals which appear to be rejects from clock manufacturers. A random error of 20 sec to 2 min a day is what I call utter ****. If you had a quartz watch which was that bad, you would take it back to the shop and demand your money back. A GPS for a time base, a good a/d converter and fast microcontroler would be the way I would do it. I am working with a very fast board 60 MHz with 4 10 bit A/D channels Does 10 bits give you enough resolution, taking into account sensor noise? The Dataq $25 starter ADCs give you 4 Channels at 240 sps total - 60 sps / channel. I can't figure out at the moment why you would need a high monitoring rate for looking at water levels? Regards, Chris Chapman
In a message dated 20/07/2005, gcouger@.......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20 size=3D2>Chris,

Out of sequence and possible not on subject but it=20= has=20 some thoughts on timing that are important. I must have come in the middle= and=20 don't understand your set up. I thought you were recording data to disk wi= th a=20 computer sound card.

I am working on a sismomenter that records sev= eral=20 sismometers at one time in the 0-50 HZ range on the two channels of a soun= d=20 card for imaging shallow aquifers looking for larger gravel to find better= =20 water well in a shallow aquifer along Red River
between Oklahoma and T= exas=20 so I can afford to put in irrigation.

I have probably imposed my=20 project on yours without realizing it.
 Hi Gordon,
 
    We were discussing sound cards and I was reject= ing=20 this as impractical for seismic purposes. The data files are massive and I=20 haven't found a way of using the 24 bit soundcard ADC for 20 sps sampling.
 
    Chuck a bit of cash at it and get rid of the yo= ur=20 problems? Larry sells a fairly good 8 channel serial board, which you can us= e=20 with a GPS receiver.
    If you want to play, fine. If you want to work,= get=20 rid of problems that you do not need to have.
    Just what rate of water rise do you get al= ong=20 the Red river?? Even for marine waves, 20 sps is adequate and most geologica= l=20 systems will go to 100sps, some even more.
 
>>    A GPS will give you the best time s= tamp=20 you could ask for some even have a 100 kHz clock as well a 1 second pulse th= at=20 are linked to GPS clocks. They can be used to phase lock frequency sources t= o=20 for super accurate osillators.
 
    I am NOT asking for the best system, just one t= hat=20 relatively inexpensive, low power and ADEQUATE for my purposes.
    I use VLF timing signals. You can get relativel= y=20 inexpensive receiver boards with a ferrite aerial: or gut a radio clock. You= get=20 about 10 mS + the transit time. The only folks who need it more accurate mon= itor=20 volcanoes of do reflection seismometry. I have been all along this road. I w= ould=20 be great if Larry would fit the software to decode WWVB directly, but he=20 seems concentrate on GPS.  GPS is power hungry and needs a clear l= ine=20 of sight to satellites; 60 KHz VLF radio is low power and can be used most=20 anywere. I can use it where I can't get MW radio, even underground. Just kee= p it=20 away from striplights, radio transmitters, TVs and computer monitors. I have= =20 used it underground near radio and TV transmitters - find a nice hole and bu= ry=20 it to screen it! It is no accident that submarine communications use=20 the VLF range of frequencies.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>If you=20 are not interested in 1 to 20 Hz signals sound cards are pretty good tools= .. If=20 you are really serious about low frequencies and accurate timing Windows p= oses=20 a lot of problems.
    0 to 10 Hz is my range of interest. I want abou= t=20 +/-0.1 sec accuracy, 24 hrs / day. This is why I use an ADC which has it's o= wn=20 on board timing and correction. The data goes to the hard disk with a time s= tamp=20 regardless of the rubbish timing on the operating system. 
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>First=20 Windows is an event driven operating system and there is no assurance when= a=20 program will run. The sound card gets around that but you have to put a ch= irp=20 on the signal to synchronize it with time you can depend on the computer c= lock=20 or the RS232 port.
    Can you say that again please? I don't quite=20 understand.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Having=20 worked with embedded systems for the last 20 years I would choose a real t= ime=20 computer. There are real time versions of Linux but I think that's over ki= ll=20 for dataloging geophones.
    You have the real and the software clocks on=20 computer boards. You used to be able to get 4.194 MHz AT crystal clocks on=20 computers, which could be made moderately reliable. All the boards that I ha= ve=20 seen recently use 32 KHz crystals which appear to be rejects from clock=20 manufacturers. A random error of 20 sec to 2 min a day is what I call utter=20 ****. If you had a quartz watch which was that bad, you would take it back t= o=20 the shop and demand your money back.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>A GPS=20 for a time base, a good a/d converter and fast microcontroler would be the= way=20 I would do it. I am working with a very fast board 60 MHz with 4 10 bit A/= D=20 channels
    Does 10 bits give you enough resolution, taking= =20 into account sensor noise? The Dataq $25 starter ADCs give you 4 Channels at= 240=20 sps total - 60 sps / channel.
    I can't figure out at the moment why you wo= uld=20 need a high monitoring rate for looking at water levels?
 
    Regards,
 
    Chris Chapman

Subject: Re: Modified sound card and datalogging and geophones From: Gordon Couger gcouger@.......... Date: Thu, 21 Jul 2005 01:03:18 -0500 ChrisAtUpw@....... wrote: > In a message dated 20/07/2005, gcouger@.......... writes: > > Chris, > > Out of sequence and possible not on subject but it has some thoughts > on timing that are important. I must have come in the middle and > don't understand your set up. I thought you were recording data to > disk with a computer sound card. > > I am working on a seismometer that records several seismometers at > one time in the 0-50 HZ range on the two channels of a sound card > for imaging shallow aquifers looking for larger gravel to find > better water well in a shallow aquifer along Red River > between Oklahoma and Texas so I can afford to put in irrigation. > > I have probably imposed my project on yours without realizing it. > > Hi Gordon, > > We were discussing sound cards and I was rejecting this as > impractical for seismic purposes. The data files are massive and I > haven't found a way of using the 24 bit soundcard ADC for 20 sps sampling. > > Chuck a bit of cash at it and get rid of the your problems? Larry > sells a fairly good 8 channel serial board, which you can use with a GPS > receiver. > If you want to play, fine. If you want to work, get rid of problems > that you do not need to have. > Just what rate of water rise do you get along the Red river?? Even > for marine waves, 20 sps is adequate and most geological systems will go > to 100sps, some even more. > > >> A GPS will give you the best time stamp you could ask for some > even have a 100 kHz clock as well a 1 second pulse that are linked to > GPS clocks. They can be used to phase lock frequency sources to for > super accurate osillators. > > I am NOT asking for the best system, just one that relatively > inexpensive, low power and ADEQUATE for my purposes. > I use VLF timing signals. You can get relatively inexpensive > receiver boards with a ferrite aerial: or gut a radio clock. You get > about 10 mS + the transit time. The only folks who need it more accurate > monitor volcanoes of do reflection seismometry. I have been all along > this road. I would be great if Larry would fit the software to decode > WWVB directly, but he seems concentrate on GPS. GPS is power hungry and > needs a clear line of sight to satellites; 60 KHz VLF radio is low power > and can be used most anywere. I can use it where I can't get MW radio, > even underground. Just keep it away from striplights, radio > transmitters, TVs and computer monitors. I have used it underground near > radio and TV transmitters - find a nice hole and bury it to screen it! > It is no accident that submarine communications use the VLF range of > frequencies. > > If you are not interested in 1 to 20 Hz signals sound cards are > pretty good tools. If you are really serious about low frequencies > and accurate timing Windows poses a lot of problems. > > 0 to 10 Hz is my range of interest. I want about +/-0.1 sec > accuracy, 24 hrs / day. This is why I use an ADC which has it's own on > board timing and correction. The data goes to the hard disk with a time > stamp regardless of the rubbish timing on the operating system. > > First Windows is an event driven operating system and there is no > assurance when a program will run. The sound card gets around that > but you have to put a chirp on the signal to synchronize it with > time you can depend on the computer clock or the RS232 port. > > Can you say that again please? I don't quite understand. > > Having worked with embedded systems for the last 20 years I would > choose a real time computer. There are real time versions of Linux > but I think that's over kill for dataloging geophones. > > You have the real and the software clocks on computer boards. You > used to be able to get 4.194 MHz AT crystal clocks on computers, which > could be made moderately reliable. All the boards that I have seen > recently use 32 KHz crystals which appear to be rejects from clock > manufacturers. A random error of 20 sec to 2 min a day is what I call > utter ****. If you had a quartz watch which was that bad, you would take > it back to the shop and demand your money back. > > A GPS for a time base, a good a/d converter and fast microcontroler > would be the way I would do it. I am working with a very fast board > 60 MHz with 4 10 bit A/D channels > > Does 10 bits give you enough resolution, taking into account sensor > noise? The Dataq $25 starter ADCs give you 4 Channels at 240 sps total - > 60 sps / channel. > I can't figure out at the moment why you would need a high > monitoring rate for looking at water levels? > > Regards, > > Chris Chapman > Chris, I am not looking for water levels I putting out sensors and making a shock moving over and making another shock ...... and another shock and resetting the sensors and doing it over again to do a seismic study of the aquifer of the water bearing sand and 30 feet down. I need a post process GPS signal to know where I am I might as well use the time spruce on it. Almost everything I work with has a GPS. I did the first vehicle units for www.ipsolutionsinc.com and all the software for spryer in http://www.ppi-far.org/ppiweb/bcrops.nsf/$webindex/6041B8CEFFC83068852568F10056A8F7/$file/97-4p15.pdf!open I agree they are power hogs and take a lot of resources for time for seismic senors that VLF will do just as well as GPS. I have seen jitter on VLF from WWV in a really bad magnetic storm but not as often as I have lost lock with the GPS. If you want to time sync a signal on a sound card you can depend on windows for time. It is too uncertain when the windows routine will time stamp it. Windows can't be made work in real time. If you want to record 0 to 20 Hz signals on a sound card a mixer and local oscillator at 500 Hz will move the 0 to 20 Hz to 500 to 520 and the inverse of it to 480 to 500. You can use DSP to get the signal back from either one. Ten bits is enough for most situations in vehicles any more is lost in the noise of the vehicle. In the case of seismometer in an open field a more sensitive A/D could be used. Gordon __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: ChrisAtUpw@....... Date: Thu, 21 Jul 2005 08:33:42 EDT In a message dated 21/07/2005, gcouger@.......... writes: Chris, I am not looking for water levels I putting out sensors and making a shock moving over and making another shock ....I need a post process GPS signal to know where I am I might as well use the time spruce on it. Hi Gordon, I understand now. We used chains of hf geophones and a pneumatic hammer.... Sure you need te position accurately as well. Do you use relative GPS to give you accuracies down to a few cm? Almost everything I work with has a GPS. I did the first vehicle units for www.ipsolutionsinc.com and all the software for spryer in http://www.ppi-far.org/ppiweb/bcrops.nsf/$webindex/6041B8CEFFC83068852568F1005 6A8F7/$file/97-4p15.pdf!open Interesting, but availablily depends on the roots being able to find nutrients and hence on the rainfall & intensity. It probably would not work too well for things like moss and poor land grasses. The grab every nutrient molecule going and store them. This was the problem in Finland after the Chernobyl nuclear disaster. The grasses and moss which fed the reindeer heards soaked up most of the radioactivity. I agree they are power hogs and take a lot of resources for time for seismic senors that VLF will do just as well as GPS. I have seen jitter on VLF from WWV in a really bad magnetic storm but not as often as I have lost lock with the GPS. I don't get this problem at all often. The computer looks for an interference free minute every half hour and then adjusts the precision crystal oscillator offset on the 59 mean pulses. The drift is initially set at less than 5 ppm and can be maintained down parts in 10^8 If you want to time sync a signal on a sound card you can depend on windows for time. It is too uncertain when the windows routine will time stamp it. Windows can't be made work in real time. Where are you getting your time stamp from? I definitely can't rely on either the software or the hardware clocks on the board. If you want to record 0 to 20 Hz signals on a sound card a mixer and local oscillator at 500 Hz will move the 0 to 20 Hz to 500 to 520 and the inverse of it to 480 to 500. You can use DSP to get the signal back from either one. Ten bits is enough for most situations in vehicles any more is lost in the noise of the vehicle. In the case of seismometer in an open field a more sensitive A/D could be used. Regards, Chris Chapman
In a message dated 21/07/2005, gcouger@.......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20 size=3D2>Chris,

I am not looking for water levels I putting out sen= sors=20 and making a shock moving over and making another shock ....I need a post=20 process GPS signal to know where
I am I might as well use the time spr= uce=20 on it.
Hi Gordon,
 
    I understand now. We used chains of hf geophone= s=20 and a pneumatic hammer.... Sure you need te position accurately as well. Do=20= you=20 use relative GPS to give you accuracies down to a few cm? 
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Almost=20 everything I work with has a GPS. I did the first vehicle units for=20 www.ipsolutionsinc.com and all the software for spryer in=20
http://www.ppi-far.org/ppiweb/bcrops.nsf/$webindex/6041B8CEFFC83068852= 568F10056A8F7/$file/97-4p15.pdf!open
    Interesting, but availablily depends on the roo= ts=20 being able to find nutrients and hence on the rainfall & intensity. It=20 probably would not work too well for things like moss and poor land grasses.= The=20 grab every nutrient molecule going and store them. This was the problem in=20 Finland after the Chernobyl nuclear disaster. The grasses and moss which fed= the=20 reindeer heards soaked up most of the radioactivity.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>I agree=20 they are power hogs and take a lot of resources for time
for seismic=20 senors that VLF will do just as well as GPS. I have
seen jitter on VLF= =20 from WWV in a really bad magnetic storm but
not as often as I have los= t=20 lock with the GPS.
    I don't get this problem at all often. The comp= uter=20 looks for an interference free minute every half hour and then adjusts the=20 precision crystal oscillator offset on the 59 mean pulses. The drift is=20 initially set at less than 5 ppm and can be maintained down parts in 10^8 <= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>If you=20 want to time sync a signal on a sound card you can depend
on windows f= or=20 time. It is too uncertain when the windows
routine will time stamp it.= =20 Windows can't be made work in real time.
    Where are you getting your time stamp from? = I=20 definitely can't rely on either the software or the hardware clocks on the=20 board.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>If you=20 want to record 0 to 20 Hz signals on a sound card a mixer and local oscill= ator=20 at 500 Hz will move the 0 to 20 Hz to 500 to 520 and the inverse of it to=20= 480=20 to 500. You can use DSP to get the signal back from either one.

Ten= =20 bits is enough for most situations in vehicles any more is lost in the noi= se=20 of the vehicle. In the case of seismometer in an open field a more sensiti= ve=20 A/D could be used.
    Regards,
 
    Chris Chapman
Subject: RE: Modified sound card and datalogging and geophones From: "Doug Crice" dcrice@............ Date: Thu, 21 Jul 2005 05:48:51 -0700 Snip I am not looking for water levels I putting out sensors and making a shock moving over and making another shock ...... and another shock and resetting the sensors and doing it over again to do a seismic study of the aquifer of the water bearing sand and 30 feet down. I need a post process GPS signal to know where I am I might as well use the time spruce on it. UnSnip This is not earthquake recording, this is exploration seismic. The frequencies you care about will be between 10 and 500 Hz and a perfectly normal sound card will handle these signals. You may need some preamps like you would with a dynamic phonograph cartridge, because the signals from geophones are small. You will need zero time from your shock source (a sledge hammer should be adequate). The best choice is a small, cheap crystal phonograph cartridge taped near the head connected to the second channel. You don't care about absolute time, just time relative to the impact, so forget GPS timing. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: ChrisAtUpw@....... Date: Thu, 21 Jul 2005 10:06:54 EDT In a message dated 21/07/2005, dcrice@............ writes: This is not earthquake recording, this is exploration seismic. You will need zero time from your shock source (a sledge hammer should be adequate). The best choice is a small, cheap crystal phonograph cartridge taped near the head connected to the second channel. You don't care about absolute time, just time relative to the impact, so forget GPS timing. I have used ordinary 13 mm piezo disks for the hammer sensor, but you do need some sort of voltage limitation to prevent input amplifier protection. The 'glass break' sensors sold for window protection work fine and are maybe less than 1/10 the price of a phono cartridge. You can use biassed current differencing amplifiers to give a ramped gain / time relationship to maintain the reflected signal strength. Regards, Chris Chapman
In a message dated 21/07/2005, dcrice@............ writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>This is=20 not earthquake recording, this is exploration seismic. 
You will n= eed=20 zero time from your shock source (a sledge hammer should be
adequate).=20= The=20 best choice is a small, cheap crystal phonograph cartridge
taped near t= he=20 head connected to the second channel. You don't care about
absolute tim= e,=20 just time relative to the impact, so forget GPS=20 timing.
    I have used ordinary 13 mm piezo disks for the=20 hammer sensor, but you do need some sort of voltage limitation to=20 prevent input amplifier protection. The 'glass break' sensors sold= for=20 window protection work fine and are maybe less than 1/10 the price of a= =20 phono cartridge. You can use biassed current differencing amplifiers to give= a=20 ramped gain / time relationship to maintain the reflected signal strength.
 
    Regards,
 
    Chris Chapman
Subject: Re: Modified sound card and datalogging and geophones From: Gordon Couger gcouger@.......... Date: Thu, 21 Jul 2005 13:21:01 -0500 Hi Chris, > > I understand now. We used chains of hf geophones and a pneumatic > hammer.... Sure you need te position accurately as well. Do you use > relative GPS to give you accuracies down to a few cm? I haven't so far. The precision of the seismic data is not that good. But I will leave temporary bench marks I can find. Since it is being farmed no till I can bury a piece of tinfoil and put up a PVC post. If the post gets knocked down a GPS and metal detector will get me back on the spot. The PVC won't hurt any equipment it happens to go through. > > Almost everything I work with has a GPS. I did the first vehicle > units for www.ipsolutionsinc.com and all the software for spryer in > http://www.ppi-far.org/ppiweb/bcrops.nsf/$webindex/6041B8CEFFC83068852568F10056A8F7/$file/97-4p15.pdf!open > > Interesting, but availablily depends on the roots being able to find > nutrients and hence on the rainfall & intensity. It probably would not > work too well for things like moss and poor land grasses. The grab every > nutrient molecule going and store them. This was the problem in Finland > after the Chernobyl nuclear disaster. The grasses and moss which fed the > reindeer heards soaked up most of the radioactivity. It works for anything we have tried it on. It measures the nitrogen in the leaves of the wheat by looking at the ratio of narrow band of red and near infrared light in late winter just before it starts the process of going from vegetative state to a fruiting or grain producing stage. In this case we are adding fertilizer to the soil in the late winter because in the vegetative state wheat uses nitrogen to grow large lush leaves and in the grain producing stage it uses much more of it to make grain and much less to make leaves. Also nitrogen is some what perishable and can leach down below the root zone if there is too much rain or turn into ammonia and escape in atmosphere if water stands on the ground. So it takes less nitrogen to produce a bushel of wheat if it put one in February than if it is put on in the previous September. By putting it down in February or March we can assure that the nitrogen in the root zone where the plant can get it when it can make the most use of it. The fertilizer could just as well be foliar fertilizer that is taken up trough the leaves. In the case of most farm crops that is not an economic option because until you get rain the plant can't benefit from the fertilizer unless the ground is wet enough to take up the fertilizer. We found several strategies that gave more return on the dollar spent on fertilizer, First was to make the nitrogen level in the wheat as near the same everywhere in the field as we could. The generally cut the fertilizer use in half and the dyed didn't change. The next was leave the areas high in nitrogen alone and double up on the low spots. That used the same amount of fertilizer and increased yields 7%. If we added in the historical yield data and added fertilizer to the point that each area had enough nitrogen to yield it full potential we got about 10% increase. I would be surprised it the system if half as could as it could be with smaller sample sizes and more experience. This only works with nutrients such as nitrogen, zinc and few others that can be applied to a growing plant and still benefit it. Other nutrients phosphorus being the most important one need to be applied before the plant spouts and immediately available to the roots. In the case of Chernobyl strontium 90 is metabolized much like phosphorus and cesium is handled like potassium. So after the rain washed the fall out off the worst problme weren't probably seen until the next year and they did make an effort in some areas to deep plow the fall out under below the root zone of the grasses and fertilize with P and K to prevent the grasses from taking up as many radioactive isotopes as they could. That only worked on land that could be plowed and that is not were reindeer generally graze. > > I agree they are power hogs and take a lot of resources for time > for seismic senors that VLF will do just as well as GPS. I have > seen jitter on VLF from WWV in a really bad magnetic storm but > not as often as I have lost lock with the GPS. > > I don't get this problem at all often. The computer looks for an > interference free minute every half hour and then adjusts the precision > crystal oscillator offset on the 59 mean pulses. The drift is initially > set at less than 5 ppm and can be maintained down parts in 10^8 The problem is not very common it takes a really big magnetic storm to cause it an they don't happen often. The 5 volt one Hz signal off a Rockwell Jupiter or many other GPS receivers makes an ideal heart beat for a clock for an microcomputer. If you need finer granularity a divider or phased locked loop on the 100 kHz output is a bit harder to build but is easier than a VLF radio. Both your way with WWV VLF and a GPS have their place. But with GPS receivers with one second clock pins selling for 25 to 50 bucks new in the box it is hard to see why any one would go to the effort to use VLF unless there were problems that precluded using a GPS. Gordon __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: Gordon Couger gcouger@.......... Date: Thu, 21 Jul 2005 13:52:05 -0500 Hi Doug > Snip > UnSnip > > This is not earthquake recording, this is exploration seismic. The > frequencies you care about will be between 10 and 500 Hz and a perfectly > normal sound card will handle these signals. You may need some preamps like > you would with a dynamic phonograph cartridge, because the signals from > geophones are small. > > You will need zero time from your shock source (a sledge hammer should be > adequate). The best choice is a small, cheap crystal phonograph cartridge > taped near the head connected to the second channel. You don't care about > absolute time, just time relative to the impact, so forget GPS timing. > I am using standard seismic sensors and I will probably use a ..22 or .38 fired into the ground or a slide hammer lifted up by a blank cartridge. My sledge hammer swinging days have been over for 20 years due to multiple sclerosis. I think I need a better clock than the computer has for relative measuring and I plan to divide down the 100 KHZ clock on the GPS to 1000 HZ and put on each channel of the sound card for a time base and reference. Each sensor will modulate an oscillator at a different frequency and all will be mixed together and recorded on the sound card and the 1000 HZ signal will be used to lock on to decoded the others as well as a time base that is automatically generated in the decoding process for each sensor. There is just too much jitter in everthing I have tested in windows to trust it to keep time even on a the sound card that is supposed to run in real time. There also has to be some point to referenced everthing from in both time and frequency. Gordon __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Modified sound card and datalogging and geophones From: "Doug Crice" dcrice@............ Date: Thu, 21 Jul 2005 12:21:30 -0700 > Snip I am using standard seismic sensors and I will probably use a .22 or .38 fired into the ground or a slide hammer lifted up by a blank cartridge. = My sledge hammer swinging days have been over for 20 years due to multiple sclerosis. > unsnip Shooting bullets into the ground is not the best energy source; most of = the energy goes into plastic deformation instead of elastic waves. There = was a source made with an 8-gague kiln gun some years ago that generated a lot = of sound and fury, but barely kept up with a sledgehammer except when fired into saturated material.=20 The best gun-like source is the buffalo gun aka "in hole shotgun". You = take a 3/4-inch pipe about 4 feet long and screw a coupling on the end big = enough to hold a shotgun shell. You auger a hole in the ground and stick the = end with the shell down a foot or more. Then you drop a pointed rod down = the pipe to detonate the shell. The shell goes off underground and much = more of the energy is coupled to the soil. It works about as well with blanks = as with loaded shells. Search for in-hole shotgun source on the web and you will find some papers. The most descriptive here http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=3Dnormal&id=3D= GPYSA70 00052000007000985000001&idtype=3Dcvips&gifs=3Dyes There is a commercial version called the Betsy Seisgun, if you search = there you can see pictures of it, but the pipe version works just as well.=20 Doug Crice http://www.geostuff.com Wireless Seismic http://www.wirelessSeismic.com 12996 Somerset Drive phone 1-530-274-4445 Grass Valley, CA 95945 USA fax 1-530-274-4446 =20 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: Gordon Couger gcouger@.......... Date: Thu, 21 Jul 2005 17:39:27 -0500 Doug Crice wrote: >>Snip > > > I am using standard seismic sensors and I will probably use a .22 or .38 > fired into the ground or a slide hammer lifted up by a blank cartridge. My > sledge hammer swinging days have been over for 20 years due to multiple > sclerosis. > > >>unsnip > > > Shooting bullets into the ground is not the best energy source; most of the > energy goes into plastic deformation instead of elastic waves. There was a > source made with an 8-gague kiln gun some years ago that generated a lot of > sound and fury, but barely kept up with a sledgehammer except when fired > into saturated material. > > The best gun-like source is the buffalo gun aka "in hole shotgun". You take > a 3/4-inch pipe about 4 feet long and screw a coupling on the end big enough > to hold a shotgun shell. You auger a hole in the ground and stick the end > with the shell down a foot or more. Then you drop a pointed rod down the > pipe to detonate the shell. The shell goes off underground and much more of > the energy is coupled to the soil. It works about as well with blanks as > with loaded shells. Search for in-hole shotgun source on the web and you > will find some papers. The most descriptive here > http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=GPYSA70 > 00052000007000985000001&idtype=cvips&gifs=yes > > There is a commercial version called the Betsy Seisgun, if you search there > you can see pictures of it, but the pipe version works just as well. > > Doug Crice http://www.geostuff.com > Wireless Seismic http://www.wirelessSeismic.com > 12996 Somerset Drive phone 1-530-274-4445 > Grass Valley, CA 95945 USA fax 1-530-274-4446 > Doug, I know a gun fired in the ground is not a good source and that's why I included a drop hammer lifted by a bank and dropped back on the rod that is attached to a steel plate that sets on the ground. I may have to use a propane to lift the slide over the piston instead of a blank shot gun shell, This fall when it cools off I will see what kind of hammer I need. Gordon __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Modified sound card and datalogging and geophones From: "Doug Crice" dcrice@............ Date: Thu, 21 Jul 2005 16:01:54 -0700 For as long as I have been in seismic, people have been trying to build = a good energy source for engineering seismic studies. Let me define such = a device for you experimenters out there. 1) A person ought to be able to carry it around 2) It needs reasonably high frequency output (ping instead of thunk) 3) Build it for $1000 or even $2000 in lots of 10 units, using new commercially available and machined parts. 4) It should be safe, even when used by students 5) There should be no significant regulatory issues (a problem with dynamite, the perfect source) 6) Operating supplies available in third world countries. 7) And last but not least, it needs to work better than a sledgehammer = used with a seismograph that can stack multiple impacts. The in-hole shotgun comes close, but it is possible to shoot yourself in = the foot, blow your hand off, and in one case, blow your brains out. The associated liability prevents any real company from producing the = device. Even if you made it impossible to accidentally hurt yourself, under our = tort system, you would still be liable for intentional injuries. Geostuff will be happy to sell the device using our worldwide network of contacts, assuming it works and is reliable. Mechanical things tend to = self destruct. =20 Doug Crice http://www.geostuff.com Wireless Seismic http://www.wirelessSeismic.com 12996 Somerset Drive phone 1-530-274-4445 Grass Valley, CA 95945 USA fax 1-530-274-4446 =20 I know a gun fired in the ground is not a good source and that's=20 why I included a drop hammer lifted by a bank and dropped back=20 on the rod that is attached to a steel plate that sets on the=20 ground. I may have to use a propane to lift the slide over the=20 piston instead of a blank shot gun shell, __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: ChrisAtUpw@....... Date: Thu, 21 Jul 2005 19:22:06 EDT In a message dated 22/07/2005, dcrice@............ writes: 7) And last but not least, it needs to work better than a sledgehammer used with a seismograph that can stack multiple impacts. Hi Doug, This may be a bit ''off the wall'', but there is another way of looking at the problem. Can we design a better type of sledge hammer + plate / falling weight? Regards, Chris Chapman
In a message dated 22/07/2005, dcrice@............ writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>7) And=20 last but not least, it needs to work better than a sledgehammer used
wi= th a=20 seismograph that can stack multiple impacts.
Hi Doug,
 
    This may be a bit ''off the wall'', but there i= s=20 another way of looking at the problem.
 
    Can we design a better type of sledge hammer +=20 plate / falling weight?
 
    Regards,
 
    Chris Chapman
Subject: RE: Modified sound card and datalogging and geophones From: "Doug Crice" dcrice@............ Date: Thu, 21 Jul 2005 16:47:11 -0700 A sledgehammer is operated by swinging it through about a 250 degree = arc, presumably by a muscular associate. If you were to replace it with a = weight drop, you would need to drop it many meters to approximate this amount = of energy. Thus, your weight needs to be accelerated somehow. There are = units that attach to vehicles with large rubber bands. They are cocked by electric or hydraulic devices. See photos on http://www.giscogeo.com/pages/giscosei.html=20 =20 We would like to make a significant improvement in energy output. You = could make a better hammer and plate, but probably not twice as good. =20 I have considered flywheel operated devices. You could spin up a = flywheel with a battery operated drill and then couple the energy into the ground somehow, though there are strange forces going in strange directions = when you suddenly stop a spinning flywheel. =20 Doug Crice http://www.geostuff.com Wireless Seismic http://www.wirelessSeismic.com 12996 Somerset Drive phone 1-530-274-4445 Grass Valley, CA 95945 USA fax 1-530-274-4446 =20 -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... = On Behalf Of ChrisAtUpw@....... Sent: Thursday, July 21, 2005 4:22 PM To: psn-l@.............. Subject: Re: Modified sound card and datalogging and geophones =20 In a message dated 22/07/2005, dcrice@............ writes: 7) And last but not least, it needs to work better than a sledgehammer = used with a seismograph that can stack multiple impacts. Hi Doug, =20 This may be a bit ''off the wall'', but there is another way of = looking at the problem.=20 =20 Can we design a better type of sledge hammer + plate / falling = weight?=20 =20 Regards, =20 Chris Chapman

A sledgehammer = is operated by swinging it through about a 250 degree arc, presumably by a muscular associate.  If you were to replace it with a weight drop, = you would need to drop it many meters to approximate this amount of energy. = Thus, your weight needs to be accelerated somehow.  There are units that = attach to vehicles with large rubber bands.  They are cocked by electric = or hydraulic devices. See photos on http://www.giscogeo.= com/pages/giscosei.html

 

We would like to make a significant = improvement in energy output. You could make a better hammer and  plate, but = probably not twice = as good.

 

 I have considered flywheel = operated devices. You could spin up a flywheel with a battery operated drill and = then couple the energy into the ground somehow, though there are strange = forces going in strange directions when you suddenly stop a spinning = flywheel.

 

 

-----Original = Message-----
From: = psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of ChrisAtUpw@.......
Sent: Thursday, July 21, = 2005 4:22 PM
To: = psn-l@..............
Subject: Re: Modified = sound card and datalogging and geophones

 

In a message dated 22/07/2005, dcrice@............ writes:

7) And last but not least, it needs to work better than a sledgehammer used
with a seismograph that can stack multiple impacts.

Hi = Doug,

 

  &nbs= p; This may be a bit ''off the wall'', but there is another way of looking at = the problem.

 

  &nbs= p; Can we design a better type of sledge hammer + plate / falling weight? =

 

  &nbs= p; Regards,

 

  &nbs= p; Chris Chapman

Subject: Re: Modified sound card and datalogging and geophones From: BOB BARNS royb1@........... Date: Thu, 21 Jul 2005 20:57:23 -0400 Doug, For a "ground-pinger": make a fitting to attach a bicycle pump to the screw cap on a large plastic (one liter?) soda-pop bottle. Bury the bottle down to the neck (or deeper) and pump until the bottle fails. (I don't know how much pressure these things will stand.) It might be better to weaken (say by scoring) the bottom so the push is vertical rather than horizontal (as when the side fails). Alternatively, the sides could be reinforced by wrapping with duct tape. This scheme meets your criteria except the "multiple impact" and possibly the "ping instead of thump" but it's hard to beat for cheap. A glass bottle might be more ping-like but would leave a hazardous residue. Bottles made of a brittle plastic (e.g., polystyrene or methyl-methacralate) might be better that the usual. It would be easy to try (but not by me). I considered pumping water instead of air but air would give greater impact because the stored enrgy is much greater. That's why pressure testing of high pressure gas tanks (e.g., oxygen) uses water rather than a gas. Another scheme:introduce a standard spark plug into a pop-bottle just below the neck. Run two wires (thru a rubber stopper in the neck or a screw cap) into the borrom of the bottle into an inch or so of water. Bury the bottle. Pass current (for a predetermined time)thru the water which fill the bottle with oxygen and hydrogen (the mixture will be stoichiometric). Fire a spark thru the plug. A stoichiometric mix of oxygen and hydrogen will detonate, not just burn. This should give a "ping". I suppose that a blanket should cover the ground above the bottle to catch the spark plug. Bob Barns Doug Crice wrote: > For as long as I have been in seismic, people have been trying to build a > good energy source for engineering seismic studies. Let me define such a > device for you experimenters out there. > > 1) A person ought to be able to carry it around > 2) It needs reasonably high frequency output (ping instead of thunk) > 3) Build it for $1000 or even $2000 in lots of 10 units, using new > commercially available and machined parts. > 4) It should be safe, even when used by students > 5) There should be no significant regulatory issues (a problem with > dynamite, the perfect source) > 6) Operating supplies available in third world countries. > 7) And last but not least, it needs to work better than a sledgehammer used > with a seismograph that can stack multiple impacts. > > The in-hole shotgun comes close, but it is possible to shoot yourself in the > foot, blow your hand off, and in one case, blow your brains out. The > associated liability prevents any real company from producing the device. > Even if you made it impossible to accidentally hurt yourself, under our tort > system, you would still be liable for intentional injuries. > > Geostuff will be happy to sell the device using our worldwide network of > contacts, assuming it works and is reliable. Mechanical things tend to self > destruct. > > Doug Crice http://www.geostuff.com > Wireless Seismic http://www.wirelessSeismic.com > 12996 Somerset Drive phone 1-530-274-4445 > Grass Valley, CA 95945 USA fax 1-530-274-4446 > > > > I know a gun fired in the ground is not a good source and that's > why I included a drop hammer lifted by a bank and dropped back > on the rod that is attached to a steel plate that sets on the > ground. I may have to use a propane to lift the slide over the > piston instead of a blank shot gun shell, > > > > > __________________________________________________________ > > 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. > > __________ NOD32 1.1175 (20050721) Information __________ > > This message was checked by NOD32 antivirus system. > http://www.eset.com > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Modified sound card and datalogging and geophones From: ChrisAtUpw@....... Date: Thu, 21 Jul 2005 21:11:32 EDT In a message dated 21/07/2005, gcouger@.......... writes: The 5 volt one Hz signal off a Rockwell Jupiter or many other GPS receivers makes an ideal heart beat for a clock for an microcomputer. If you need finer granularity a divider or phased locked loop on the 100 kHz output is