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VK5QX > INFO 24.08.02 06:42l 84 Lines 2948 Bytes #999 (0) @ WW
BID : DE0323VK5QX
Read: DB0FHN GUEST
Subj: Re: Omega/UNDERGROUND ANTENNAS
Path: DB0FHN<DB0ZWI<DB0MAB<DB0FBG<DB0TUD<DB0GRL<SR6BBA<OK0PCC<OK0NAG<OK0PPL<
RZ6HXA<IK1ZNW<HA3PG<VK3AVE<VK5BRC<VK5SPG<VK5LZ
Sent: 020823/0747Z @:VK5LZ.#ADL.#SA.AUS.OC #:42525 [Elizabeth] $:DE0323VK5QX
From: VK5QX@VK5LZ.#ADL.#SA.AUS.OC
To : INFO@WW
ANY ADDITIONAL INFORMATION ?
It was most interesting to note the comments provided by Jerry K0CQ on the
matter of "underground antennas".
I was quite pleased to see something from another source that seemed to
corroborate the information that I provided in a previous bulletin.
He said,
__________
" The lower frequency submarine communications use(d) frequencies more
like 65 to 90 Hz, essentially unbalanced power lines over large blocks
of rock that gave them a decent loop aperture. "
__________
Jerry's terminology with the word "use(d)" probably indicates some
uncertainty as to whether or not such a system still exists.
I do not currently have any convenient way to try and "listen" to or
determine as to whether any form of signal is present at such a frequency
as suggested.
In the previous bulletin mentioned, I had referred to information obtained
in discussion with a friend, where I said,
" The operating frequency was in the Extra Low Frequency (ELF) portion
of the spectrum, around 72 Hz, also referred to as being "sub audio".
It used a "current loop" approach with antenna wires which were relatively
close to the ground. Possibly a maximum height of about 10 feet. A method
of "earth return" was employed to complete the loop.
The length of the wires was (believe it or not) in the order of 100 MILES.
It is possible that there were TWO separate wires in a cross pattern.
The earth return system necessitated earthing leads buried a long way
down, so as to achieve the "loop" effect. This was also necessary due to
the poor or non-conductive characteristics of the rocky ground. "
__________
Now, looking again at the comments made by my friend I note that he
referred to the fact that certain rock was "non-conductive".
From this I have to assume (reasonably, I feel) that the rock must act as
an insulator.
Carrying on from this assumption, and the comment made by Jerry K0CQ, one
might also theorise that the large lump of "insulating" rock did allow a
(resonant) loop to exist, in a similar manner as any wire loop such as
used in many cases of present antenna practice.
Hence, we may have some enlightenment on the subject under discussion.
As I previously indicated, I could not find anything of major consequence
on the Internet regarding this subject.
Perhaps the attempts at communication using such a system were a failure,
OR, maybe the matter is so classified that nothing much else has leaked
out about such a system.
It would be interesting to hear a little more on this subject.
I am quite puzzled as to the actual mechanism of propagation of signals
where an antenna of this nature is used. Perhaps it is a method whereby a
very strong ground wave can be set up and which provides very wide
coverage.
Any further contributions anyone ??
Regards,
Ian
__________
73 de Ian, VK5QX
@ VK5LZ.#ADL.#SA.AUS.OC
23 August 2002
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