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ZL3TPN > INFO 25.08.02 13:46l 74 Lines 4026 Bytes #999 (0) @ WW
BID : ZL3TPN328155
Read: DB0FHN GUEST
Subj: Re: Omega/UNDERGROUND ANTENNAS
Path: DB0FHN<DB0ZWI<DB0MAB<DB0FBG<DB0TUD<DB0GRL<SR6BBA<OK0PCC<OK0PKL<OK0PPL<
RZ6HXA<SP7MGD<SR3BGN<WB0TAX<N2BQF<PY2DML<ZL2BAU<ZL2BAU<ZL2WA<ZL2TZE<
ZL2SUN
Sent: 020826/0905Z @:ZL2SUN.#70.NZL.OC #:39109 [Nelson, NZ] $:ZL3TPN328155
From: ZL3TPN@ZL2SUN.#70.NZL.OC
To : INFO@WW
>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.
>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
I have a contribution that may or may not add to the topic,...
At Christchurch Airport there is an American Airforce Base that is used for
the supplying of the Antartic operations at McMerdo and Ross Base and as a
coincidence just outside of Chrischurch on the south coast there is a long
spit of land (30km) between the sea and a shallow lake,on this spit there is
a radio station that is used for communications to the South Pole and is able
to be used when QRN is very high at other stations and especially the South
Pole. They are suppose to use ELF to combat the QRN.
When going past the area of the station, I've noticed that a single phase
has been strung on high poles and leads off into the direction of the spit
and I've thought that this may have something to do with the ELF stations
aerial system. It may be possible to modulate on these power lines an ELF
signal and still use them for general electricity distribution. I may
be barking up the wrong pole and it may be just a short cut for an extra
phase needed by a farm down the other end of the spit????
73's Nick -- ZL3TPN
T4 1.5à23
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