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Old June 29th 04, 04:58 PM
Cecil Moore
 
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The Eternal Squire wrote:
Question: to what extent can I shorten the winding while still
retaining good signal apeture? about 50 %? More? And what would I
need to do (if anything) to compensate for this?


75m mobile antennas are shortened by as much as 88%. Of course,
they are not very efficient. But a 50% shortening should result
in an acceptable amount of loss. However, hi-Q loading coils are
more efficient than helical windings. Tell everyone that the
loading coils are varmint guards (snakes, squirrels) for your
"birdhouses". A top hat could be disguised as bird perches and
would raise the efficiency of your antenna elements.

On another note, peak performance from a vertical array requires
phasing/matching at the feedpoints. Roy, W7EL, has a computer
program that will calculate the lengths of the phasing sections
for you - available at www.eznec.com.
--
73, Cecil http://www.qsl.net/w5dxp



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