>
> . It is simply not true
> that we all need to have a rich uncle who own Chilean copper mine in order
> to be successful with our low-band antennas, ~73~ de Eddy VE3CUI -
>
Physics doesn't much care whether we are rich or penniless, and being a
religiously pro-radial bigot or anti-copper enthusiast does not change the
simple physics of the matter. It is what it is.
A single raised "radial" is an unopposed horizontal conductor, simply, and
only, a low horizontal wire.
Assuming we are not talking about running this antenna over salt water, and
without any particular statement whether radials above ground, on, or under
are better (rightly controversial, IMHO)...
While a single "radial" DOES act as a low loss current sink for the coax
shield, it does not address at all the two other major loss issues addressed
by a dense radial field:
1. Electric field penetration of the ground directly below and up to ~1/8
wave radius from the vertical conductor. Without the shielding effects of
dense radials this goes directly to loss.
2. Ground absorbtion of below horizon magnetic radiation from the vertical
radiator. Some portion of this is reflected skyward where the radials are
"dense enough". Without it ALL of the vertically polarized below horizon
radiation is lost.
The improvement or worsening of the loss in 1 and 2 will occur without much
change in SWR. In fact the WORSE the loss in 1 and 2, the BETTER the SWR
off the precise match frequency.
SWR only indicates how well a circuit is matched to 50 ohms J0. Under a
great many circumstances, broad low SWR is in an inverse relationship to
performance.
73, Guy.
_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M
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