PSN-L Email List Message
Subject: Re: Digging in...
From: Gordon Couger gcouger@..........
Date: Sat, 13 Aug 2005 16:07:05 -0500
> 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?
> > Are they the 4.5 Hz geophones?
> 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
> (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.
> 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
http://www.couger.com/ranch.gif 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.
http://www.maxstream.net/products/index.php If you want plug and play.
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