PSN-L Email List Message

Subject: Question about sensitivity.
From: "John D Nelson" jnelson@.................
Date: Mon, 21 Jul 2003 10:02:12 -0500


I have a geophone with a 10 hz resonant frequency and a home made
vertical with a period of about one second.  Does the lower resonant
frequency make the vertical less sensitive to local noise?  My
observations seem to back this up.  There is a NAFTA rail line about 2
miles East of my house that makes a lot of low frequency noise and the
geophone seems to pick it up more than the vertical.  I'm using the same
amplifier for each, John Lahr's circuit with an additional 2 pole filter
added on at the end which I thought would pretty much cut out local
noise but this doesn't seem to be the case.

Message



I have = a geophone=20 with a 10 hz resonant frequency and a home made vertical with a period = of about=20 one second.  Does the lower resonant frequency make the vertical = less=20 sensitive to local noise?  My observations seem to back this = up. =20 There is a NAFTA rail line about 2 miles East of my house that makes a = lot of=20 low frequency noise and the geophone seems to pick it up more than the=20 vertical.  I'm using the same amplifier for each, John Lahr's = circuit with=20 an additional 2 pole filter added on at the end which I thought would = pretty=20 much cut out local noise but this doesn't seem to be the=20 case.

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