I think you will find the whip, loading coil and capacity hat make a
series resonant circuit on 80 meters. Much like a base loaded mobile
whip and coil. That is will make most any short length (much less than a
quarter wave) support under it work near its series resonant frequency
and that the resonant frequency is pretty much independent of the
support, but highly dependent on the whip and capacity hat above the coil.
And that on the higher bands the inductance of the coil will act mostly
like an RF choke and keep RF from appearing on the whip and capacity
hat, kind of like a trap, but without being single band.
On 2/18/2011 1:06 AM, Malcolm McLeman wrote:
I have a hygain 18AVT antenna of which I want to use the top section
ie whip, loading coil and capacitance hat for a home-brew vertical
without traps. Anyone out there give me some idea of the theoretical
paramaters of this top section? 73 Malcolm/F5VBU
73, Jerry, K0CQ
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