On 10/27/20 12:17 PM, Paul Christensen wrote:
"Unrelated: In the Nov. QST in the Doctor Is In column, the author Joel
Hallas W1ZR, states that a 180 degree base fed vertical monopole needs no
ground system, only "short counterpoise rods, which look like radials but
are usually only 4-6 feet long, to provide a connection point for the shield
of the coax." That is utterly incorrect. It is voltage fed, but it is
still a monopole, and is still unbalanced and induces currents in the earth.
It needs a ground system."
Rob is correct. If a 180-degree base-fed radiator at ground level didn't
require an adequate radial field to capture return current, AM broadcast
stations with 180-195 degree vertical radiators like WLS, WSM, and WLW have
all wasted a lot of money over the last 90 years.
One might want to distinguish between "radials as part of antenna" and
"radials as something that reduces loss in the soil in the near field"
180 degree base fed radiators probably fall in the latter case. That
is, there shouldn't be any current flowing at the end of the radial
closest to the antenna.
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