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Re: LF: David Gibson on Earth antennas and propagation below 9 kHz

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Subject: Re: LF: David Gibson on Earth antennas and propagation below 9 kHz
From: Stefan Schäfer <[email protected]>
Date: Tue, 27 Jul 2010 17:29:13 +0200
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YES! Very fine John! What do you plan? Which QRG and which wire length? My hint is to use a mountain if you have one beside your QTH.
Whish fun and good luck and await your results/report!

73, Stefan

Am 27.07.2010 16:53, schrieb John Rabson:
Andy,

I hope to be doing some aerial  experiments (yes - above ground not below) in the next few weeks and will see if I can put something up and do some measurements.

73
John F5VLF

On 26 Jul 2010, at 16:09CEST, Andy Talbot wrote:

I was thinking about this, and thoughts turned to a rather simpler antenna;  the folded dipole and how it would behave when electrically short.
 
A simple non-folded  electrically short dipole (negelecting all losses)  has Rin proportional to 1/L^2 and a highly capacitive reactive term
 
A folded half-wave dipole fed conventionally has Rin about 4* that of a normal dipole due to current sharing in the legs -.
 
Now the conumdrum - what does an electrically short folded dipole look like?     It has got to be inductive, since we're feeding into a squashed shorted turn, and presumably the current distribution looks short dipole-ish.
 
So is it a loop, is it a dipole, is it both, how can it be both, if it is what's its radiation pattern ?
Similar to the ground loop/dipole question ?
 
And is there a length where the inductance of the loop bit resonates with the capacitance that 'ought' to be there due to its also being a short dipole.
 
?????????????????????????????????????
 
(not really an antenna sort of person)

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