I'd like to suggest a pair of phased delta loops. I have such an antenna
and it works very well.
The apices are supported by a 20' PVC crossarm at 66' on the tower. The
equilateral triangle loops are tilted away from the tower so the base
leg is 40-50 feet apart, and run parallel to the ground, about 6-8 feet
above it. They are fed 1/4 wavelength from the top which gives vertical
polarization. The natural loop impedance is around 100 ohms, which can
be matched to 50 ohms with a 75 ohm section. The two antennas are fed
with a relay arrangement which provides 180 degree switching, so only 2
directions are possible. Gain is similar to four-square.
The antenna provides vertical polarization for good low angle DX
performance. The base leg acts as a counterpoise, so no radials are
needed, and low ground conductivity does not adversely affect
performance. The frequency can be simply changed from CW to phone from
ground level by adding stubs at the center of the base leg.
Feed system details available on request.
-Tony, K1KP
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