Mark Keith wrote:
"Tom Coates" wrote in message ...
The writeup says the terminating resistors make it non-resonant. I wonder
how they affect efficiency.

Seems to me it's already non resonant except on certain frequencies
where it's multiples of a 1/2 wave. But you do have reactance on most
frequencies. The resisters absorb rf that travels along the wire to
the resister. The rf traveling to the rig in the other direction, is
absorbed by that load. So there are no standing waves. Basically, all
the resisters do is make the antenna fairly unidirectional. About the
same deal as a terminated rhombic. You have a good f/b ratio. But
overall total efficiency is appx cut in half, being the waves to the
resister are absorbed. I think this is correct anyway...:/ MK

What Tom probably means is that the resistors turn the antenna into a
traveling wave antenna where the feedpoint impedance is a few hundred
ohms mostly resistive over a relatively wide range of frequencies. It
is somewhat like that infinite feedline that we sometimes talk about.
--
73, Cecil http://www.qsl.net/w5dxp



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