The HALF-WAVE T-TOP ANTENNA described by VK3APN
(approximately 1/2 wavelength from bottom of the T to each end at the top
and fed at the top) will exhibit a high impedance (and there high
voltage) at all 3 terminals of the antenna, including the base, and the
high CURRENT portion which does all the radiating will be on the
HORIZONTAL portion. Basically, this structure will act as a LOW
HORIZONTAL wire antenna with little vertical polarization.
A QUARTER-WAVELENGTH T-TOP ANTENNA is a very efficient means of achieving
a shortened vertically polarized radiator if fed against a good ground
system. I suppose it could be fed at the end of one of the top pieces if
the base is connected directly to the ground system. This method would
also work with an inverted L of similar dimensions, except that for the
inverted-L there would also be a secondary horizontally polarized
component.
de Tom - N4KG
:
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