PSN-L Email List Message

Subject: Re: Digging in...
From: Gordon Couger gcouger@..........
Date: Sat, 13 Aug 2005 16:07:05 -0500

ChrisAtUpw@....... wrote:

 > In a message dated 13/08/2005, dwieck@............ writes:
 >     >     Is it a timber house or one with brick/stone walls?
 >     Its brick
 >     > How many stories?
 >     2
 >     >     Are they the 4.5 Hz geophones?
 >     yes
 > Hi Dennis,
 > >     You have the problem of long cable runs and probably
 > > some lightning protection required for installations away from the 
 > >> I am used to this. I am a ham and have dealt with tower and coax to my
 > radios grounding.
 >     Great. There is a lot of ham literature on protection for radio 
 >     Is there a problem with moderate (probably less than 100 ft) runs
 >     between the geophones and the amp/filter/A/D or do I need to 
remote them
 >     (that adds to the waterproof question)?
 >     This depends a lot on your soil conductivity. Wiring under the 
house is likely to be partly shielded by the house 'earth'. 100 ft is 
quite a long external 'aerial'. I would be inclined to fit some 
lightning protection where the cable enters the house, especially if 
lightning is a 'problem' in your area. A burnt out seismic system + 
computer would be expensive. Remember that you get ground currents for 
quite some distance around a lightning strike.
 >     Is the utility power wiring to your house below ground or on 
poles?  Elevated wiring does tend to pick up stronger lightning surges, 
sometimes from many miles away.

 >    Regards,

 >     Chris Chapman

To beat long cable runs and the associated problems wireless data links 
are just becoming a reasonably priced off the rack solutions that is 
reasonably easy to put in to practice. Using directional antennas Zigbee 
and BlueTooth can work several hundred yard in the clear. I it a bit 
more than most of us would want to undertake but for one very quite site that is two miles off a lightly traveled 
high way and has NO traffic at night I have to have a wireless link to 
the phone lines so I can be several miles away from power lines as well. 
I will probably use something with more range than BlueTooht some hams 
are getting 3 miles with 802.11 B wireless cards made for office 
automation. That would take a large solar powered installation but in 
the scope of what I have in mind.

Maxsteam has good off the rack stuff that I know works. If you want plug and play.


Gordon Couger
Stillwater, OK


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