PSN-L Email List Message

Subject: Re: Tiltmeter progress
From: "tchannel" tchannel@..............
Date: Wed, 4 Apr 2007 11:59:14 -0600

Hi George,  This is interesting.  Where can I find articles to read more 
about the basic principle. etc.   Thanks, Ted
----- Original Message ----- 
From: "George Bush" 
Sent: Wednesday, April 04, 2007 11:01 AM
Subject: Tiltmeter progress

> Chris-
> I wanted to report on my recent activity with the tiltmeter (NOT the
> tiltometer!).
> Your last comment to me about the Linear LTC1043 circuit going unstable if
> the Cx is smaller than the Cref has opened a door and I am now proceeding.
> Knowing that the circuit was working was of great value and I stopped
> trouble-shooting and have attached the circuit to the tiltmeter yesterday!
> The instrument is amazingly stable, no apparent noise on the scope, no
> sensitivity to moving my hands near the un-shielded Hg pots and it seems 
> to
> just simply work.
> I did a simple sensitivy check. The plate the two pots are mounted on is
> supported by screws in a triangle configuration (see
> The pots are separated by 24" center-to-center, and the micrometer 
> leveller
> leg is separated from the other end two suppoort screws by 27 1/2". When I
> adjusted the micrometer by .01" vertically, I got an output voltage change
> reading of 0.193v. If my trig is correct this is the voltage change for a
> tilt change of 6.347 -07 deg. I have no feeling if this is getting into 
> the
> ball-park of sensitivity needed to detect Earth tides. What sensitivity do
> you think is needed?
> Since yesterday afternoon I have periodically recorded output voltage and
> time. This is the signal so far:
> Date Time Vout
> ---- ---- ----
> 3-4-07 1:21p 1.625
> 3:45p 1.594
> 5:27p 1.605
> 6:30p 1.615
> 4-4-07 9:29a 1.654
> Presently I am connecting the instrument to my Windaq DI-194 to try to 
> plot
> daily signal variations. Then I will be able to see if I need to add
> another stage of gain. After that, a complete mechanical tear-down to
> shield the Hg cups and connecting tube and to build an insulated enclosure
> with a heater in the top.
> I can see light at the end of the tunnel and am really geting excited!
> George
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