> Any thoughts and or practical experience would be appreciated! Many
> thanks for your help.
>
> 73
>
> Bob KQ2M
>
Hi Bob,
Elevated radials radiate like crazy in close to the radial, and couple
to everything around the radial. There is nothing you can do about
that radiation, it always happens.
Remember what causes radiation, and what prevents it. In close to
the wires, you will have very strong magnetic and electric induction
fields. You will also have radiation that can only be cancelled by an
opposing field that is out-of-phase and EQUAL to the fields causing
problems. If you have four radials, you have 1/4th the current in
each radial that you have in the vertical (less whatever follows the
outside of the feedline shield away from the antenna making the
coax radiate).
If you run 1500 watts, you can consider that each radial is an
antenna tied to a ~200 watt transmitter. The radiation from the
radials caused by direct excitation of the radial by the transmitter,
even in the best case, only cancels in the far field many
wavelengths from the radial.
It is difficult or impossible to predict the effects when you put a
bunch of radiating wires together in a small area, but it likely won't
be very much of an advantage!
You not only suffer a loss of efficiency by having a small ground
system, it aggravates RFI and coupling problems to other nearby
conductors that are not part of the antenna system you are using.
73, Tom W8JI
W8JI@contesting.com
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