Re: LF: RE: DLF passive received with earth antenna

[Roger Lapthorn <rogerlapthorn@gmail.com>]

This sounds an interesting talk. Where is this conference being held please? 

Perhaps with Heyphones and Nicola systems working in the 40-90kHz region these antennas do behave differently.  At 500kHz I'm convinced the earth electrode structure behaves as a loop based on the reports I've received and directionality. I suspect the same is true at 136kHz .

At ELF/VLF I think the earth electrode pair must act in several ways 
simultaneously.

(a) As an induction loop. This certainly ties up with behaviour and loop orientation locally in my experiments away from buried cables.

(b) As a means of producing a potential difference in the ground for earth mode (conduction) communication. Again, this is how I understand my "utilities assisted DX" is being achieved on 838Hz with the signal being largely conducted along buried pipework and cables and the last few metres being inductively coupled into my loop receiver. I can't see how else just 4W can get so far.

(b) As an inefficient and lossy dipole radiating a tiny signal.

It would be most interesting to read about the ELF antennas used for Project Sanguine and the theory behind these. These (miles long) antennas were grounded at each end and the grounding was important for the system to radiate an ELF signal detectable in the deep oceans at 76Hz. 

Has Dr Gibson written anything already to give us a clue what he thinks is going on?

73s
Roger G3XBM

On 15 July 2010 17:52, John Rabson <john.rabson@numeo.fr> wrote:

Members of the Cave Radio & Electronics Group have been using and investigating earth loop antennas for some time. The theoretical basis of such an antenna has not been clear to us, but Dr David Gibson of CREG is proposing to give the following lecture at the Hidden Earth conference in the UK this autumn.

How earth-current antennas really work
--------------------------------------
With cave radio equipment such as the HeyPhone and Nicola system there
has been a trend away from the use of induction loop antennas towards
earth-current antennas, i.e. long wires grounded at both ends. However,
the popular explanation for how these antennas work is fallacious. They
do not operate by allowing the current to flow in a 'big loop' in the
ground and in fact, they do not depend, fundamentally, on current flow
in the ground at all.

The fact that the popular explanation is wrong is important because, if
we do not understand how the antenna works, it is difficult to know the
best way to use it, or how to design a better one. Back in 2003, I wrote
an article for the CREG journal entitled 'What We Don't Know About
Earth-Current Propagation'. It has taken me some time to get to grips
with the problem but this talk will now go some way to filling in the
gaps in this knowledge and will describe a method of experimentally
rating earth-current antennas for effectiveness.

--
David Gibson

-- 
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
G3XBM    GQRP 1678      ISWL G11088