Hi John and Group.
On Mon, 20 May 2002, john sexton wrote:
Putting in the same antenna details as before, the new formula gives 38 ohms,
still too low by a factor of over 2, but much better than with the first
formula.
May be 93 - 38 = 55 ohms is enviroment loss. And if make conterpoise up
from the ground about 1 or 2 meters, ground loss reduces from 38 to about
5omhs. So total loss will be 55+5=60 omhs. But it is the matter of
experiment...
It seems very interesting and worth to do 'pure' experiment in field
far from trees and buildings when no enviroment losses present and when
conterpoise is up from the ground and conterpoise length is equal to
antenna length. NEC-2 confirms the formula but this is only computer
modeling, not real measurement!
If it will be no problem to estimate ground loss itself then it will be
posible to separate ground and enviroment losses when doing experiments.
So experimental study of enviroment losses itself will be possible and
ways to reduce enviroment loss will become more obvious. Now we do not
know what part of total loss is ground loss and what is enviroment loss
itself.
However in order to do this since my earth wires are actually buried I used
a value of h = .0005 (1mm diam. wire) the minimum value permitted with your
formula.
It seems reasonable.
My generalised mirror reflection theory can be used for burred conterpoise
also I hope. It is only matter of time. Now I want to ensure this
theory for simple conditions. Complex conditions is a next step.
73 de RA9MB/Alex
http://www.qsl.net/ra9mb
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