> The 43' vertical is much too tall to be usable on 15 and particularly
> 10 meters.
Seems to me the 43-foot verticals are reasonably good for operation between
40M-20M where the lobes are contained to low angles and where the antenna
can achieve good radiation efficiency without top-loading.
Back to the original topic as to the optimal vertical length...For base-fed
verticals, my vote is for a radiator of 190-195 degrees where the zero
degree elevation field strength is maximum, while minimizing high angle
lobes. Ideally, something like a SteppIR vertical would be used on all
bands with a suitable motorized base matching network. Of course, the
reality is that such an antenna would be difficult to make for operation on
160M, and even 80M.
If one could only find a 260-foot support to hang a vertical wire, then a
motor could be used with a pulley system to optimize the vertical length to
achieve the 195 degree radiator on all bands -- much like the SteppIR, but
on a near half-wave scale for all bands. An adjustable, motorized base
network would be required to match the Hi-Z operating impedance of the near
half-wave radiator for coaxial lines. OTOH, if I had access to a 260-ft
support, I would probably be using it for other antenna types as well.
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