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Underground activity surveillance...

Posted: Tue Jun 19, 2007 2:24 pm
by Externet
Hi fellows.
A few years ago, there was an amateur group, unsure if most of them a branch of ham radio operators, dedicated to monitor and record underground noises and electrical noises related to creeping of geological faults.
They used inexpensive surplus geophones.

Cannot find them now, anyone knows of its activity? :sad:


Posted: Tue Jun 19, 2007 4:09 pm
by Chris Smith
Last time I saw a Geophone was in Halted Specialities, Fair Radio sales, or the surplus store in Pasadena [?] C & H or a similar name.

Posted: Tue Jun 19, 2007 4:29 pm
by haklesup
Do you mean the group or the component?

There is one ebay auction now for a geophone and amplifier board $25. It seems to operate like a VU meter with a row of LEDs. Just search on geophone. Seems to have a bunch and no end date in the auction for now.

I think I got mine years ago at MPJA but they don't seem to have any now.

Groups come and go. If they haven't found a home on Yahoo, many just migrate to usenet groups.

Posted: Tue Jun 19, 2007 7:13 pm
by Externet
Hi haklesup.
Ooops, unclear... yes, I meant the group, was active on the net in ~ 1998.
Geophones are easy to find.
Will try usenets, if I find out what is the difference between a usenet and a plain not-usenet ? site :smile:

Posted: Tue Jun 26, 2007 10:54 pm
usenet is an old public emailbox system that predates web sites,
sort of like how irc chat predates "chat rooms" and web sites,
usually it's text only unless your gateway is a website or applet.

In other words, it works even with those really slow old modems.