The Bison 1580 is an exploration seismograph, not an earthquake
seismograph.  It's generally used with a sledgehammer energy source to
do shallow refraction surveys like depth-to-bedrock and such.  It's a
member of the class called "signal enhancement" seismographs because it
can store the data from a hammer impact in a digital memory, and then
add the signals from subsequent hammer blows to give you more range
without resorting to explosives. It wasn't ever a commercial success
because of logistic considerations related to the number of channels. It
doesn't contain much in the way of components useful for earthquake
recording but would be useful for checking out your foundation if it
works.  The schematics were never public knowledge and Bison went
bankrupt just last year.  There is a group in Minnapolis alegedly
provding service.

"Raul J. Alvarez" wrote:
> 
> Hi All,
> 
> Seismo amp on ebay.  Check it out if interested.
> http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=200548268
> 
-- 
Doug Crice          web site http://www.georadar.com
GeoRadar Inc.             e-mail dcrice@............
19623 Via Escuela Drive           phone 408-867-3792
Saratoga, CA 95070 USA              fax 408-867-4900

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