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Re: Test results

At 22:25 8/14/96 -0600, you wrote:

>
>>From rwstephens-at-ptbo.igs-dot-netWed Aug 14 21:25:14 1996
>Date: Tue, 13 Aug 1996 23:37:08 -0500
>From: "Robert W. Stephens" <rwstephens-at-ptbo.igs-dot-net>
>To: tesla-at-pupman-dot-com
>Cc: jim.fosse-at-bdt-dot-com
>Subject: Re: Test results


      <big snip>

>I second Jim's suggestion that 
>you attempt to send a swept frequency chirp through the medium under 
>test to try to establish that at a short distance at least, is there 
>any frequency preference curve.
>
>I would like to suggest another, more ambitious experiment.  Not 
>unlike an amateur radio operator attempting to obtain a faint echo of 
>a transmitted radio wave pulse back from the moon, have you 
>considered transmitting a short tone burst pulse of considerable 
>power into the earth through your ground rods, and then immediately 
>after transmission, connecting the rods through a TR 
>(transmit/receive) switch hooking up to a sensitive receiver and 
>chart recorder employing a narrow band pass filter  set to the transmitter
>frequency, in an attempt to measure backscatter from, nearby geological 
>subterranean strata and techtonics, and hopefully long route passes around the
>crust of the planet, or perhaps lensed or otherwise reflex action through
the core
>of the earth and back.  Your weak echoes, if present would be identifiable 
>at least by their fixed, repeatable time delay compared to your TX pulse.  You 
>might try this experiment initially at your 7 Hz, and if successful 
>in receiving returns, you could then employ a chirp as suggested by 
>Jim.
>
>The experiment that begs to be tried using an actual Tesla coil if 
>the earth can be found to be a resonant (echo producing) ground counterpoise
>over a narrow frequency window which may be measureable with modern
>equipment will be obvious. 
> 
>Regards, rwstephens  

Thanks for the suggestion Robert.

Sometime ago (around 2 years) we did research this idea with some varying
results. Our main problem at the time was that even though we were receiving
echos we lacked the equipment to measure the time domain reflections with
any accuracy. I found that by using a switching device between the transmitting
and receiving equipment, (multiplexing) we were able to obtain echos which 
varied largely over different types of terrain. It would be neat if there
was a way to interface a type of display such as a sonar depth finder.
It sure would be a helpful tool for a lot of purposes.

Thanks for the interest and questions.


Charlie
 
Elfrad Group