Topband: High Z vs Low Z shunt feed tower

Maurizio Panicara
Mon, 6 Nov 2000 22:31:04 +0100

In any case, a tower needs to be shorter than electrical quarter wavelength,
or anyway Z=R-Jx , to be suitable for canonical gamma or omega matching.
Concerning tap point impedance, calculations are slightly more complicated
with a gamma match because some series parallel transformations have to be
performed before having it in the series form.
The statement that "more capacity is better" in a gamma match is not a dogma
and has to be properly applied knowing why something is done and what's the
limit beyond the process is producing no enhancements and possibly
delivering problems.
Playing on tap and diameter ratios between antenna and gamma wire it's
virtually possible to design a gamma that requires a huge capacitance, but
this is not reccomendable and practically becomes useless.

Mauri I4JMY

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