I may be seriously wrong, but shorter than 1/4 wave ground
mounted radials are probably affected by the same ground tuning
effects that allow a Beverage on the Ground antenna to be
considerably shorter than one mounted above the ground. If this
is really what is going on, then a bit longer than 1/8 wave
should be about right for radials on/under the ground.
73 Bill AE6JV
On 12/29/16 at 9:05 AM, donw...@embarqmail.com (Don Wilhelm) wrote:
With buried radials, they do not have to be 1/4 wave long, and
a single one will probably not make much difference over your
ground rod.
What you want to accomplish is a "ground screen", which means
many short (about 1/8 wavelength) close to the base of the
radiator and a few extending out further (to 1/4 or 1/2 wavelength).
Ground conductivity plays a great part in buried radials, and
what you are trying to accomplish is to increase the ground
conductivity in the area at the base of the antenna.
If you were instead using elevated radials, they would have to
be resonant - think of the various "ground plane" antennas that
have been published - 1/4 wave radiator plus 2 or 4 1/4 wave radials.
Buried radials do not have to be resonant, elevated radials
must be resonant. The ground effects will alter the resonance
of buried radials while radials in the air are a part of the
total antenna resonance.
-----------------------------------------------------------------------
Bill Frantz |Security, like correctness, is| Periwinkle
(408)356-8506 |not an add-on feature. - Attr-| 16345
Englewood Ave
www.pwpconsult.com |ibuted to Andrew Tanenbaum | Los Gatos,
CA 95032
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