In message , Spike
writes
On 30/11/2015 23:53, wrote:
In rec.radio.amateur.antenna Spike wrote:

The effective soil conductivity will be close to the fully conductive
value of the fibres - that's what percolation does. The high aspect
ratio fibres are a method of achieving that in a poorly conductive
medium such as soil.

One can not enter text into a model; numbers please.

Much of this has already been done, 'this' meaning studying the effects
of ground conductivity and number of radials (going up to 64) by N6LF
in QEX with the latest version being published in September/October
this year.

Note for Brian Howie: the study encompasses 472 kHz, and it should be
noted that below 1MHz the soil electromagnetic parameters diverge
significantly from HF values. This implies that a different approach is
needed, and one of the articles looks at this - you might find this of
interest.

Thanks I've had a look at them . If I ever get round to transmitting
there, I'll need a lot of earth.

I'm still using my 5 foot loop for receive, but it's now series tuned,
rather than parallel with a coupling loop and seems to work a bit
better.

By coincidence my morning training run took me near the EDN NDB

http://www.b-howie.demon.co.uk/lfbcon.htm

It's a top loaded vertical, but looking over the fence, I could see a
lot green earth wire radials on the surface. It's possible there are
buried ones too , but there are only about 6 and they can't be more than
15ft long,

Brian
--
Brian Howie