On 1/13/2018 07:44, Don Wilhelm wrote:
All information I have seen says that the counterpoise needed for an
EFHW is 0.05 wavelength - at 40 meters, that is about 3.5 feet.
If you make it longer than that, it becomes an offset center fed
antenna, longer than a halfwave, in other words, it is a random length
wire. Both the half wavelength wire and the counterpoise wire will
radiate.
True, and the longer the counterpoise, the more it will radiate, right
into the ground if it's just lying on the ground, so there's really no
point in a longer counterpoise for the EFHW.
One extreme case is the center-fed full wave, or "two half waves in
phase". It has the high feedpoint impedance of the EFHW (actually about
double) and has a pattern much like a dipole, but sharper. It has a
couple dB of gain over a dipole broadside but, of course, less gain in
other directions.
73,
Scott K9MA
--
Scott K9MA
k...@sdellington.us
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