Mike Waters W0BTU wrote:
>> From: dick-bingham <dick-bingham@hughes.net>
>> Subject: Re: 100 Watts
>> To: "Mike Waters W0BTU" <mrscience65704@yahoo.com>
>> Date: Thursday, February 18, 2010, 8:34 PM
>> Nope !! A half-wave
>> end-fed antenna feedpoint is a very high impedance
>> (it's an open circuit at both ends and therefore virtually
>> a zero-current point) which is easily fed using a parallel-L-C network.
>
> I mostly agree. Years ago, I had a half-wave vertical for 20 meters,
with 4 elevated radials, and that's how I fed it. I used to work VK's
and ZL's nightly with it from my old QTH in NW Ohio.
>
> [snip]
>
> It's true that the radial current _at the feedpoint_ is lower than
a 1/4 wave (or shorter) vertical. But I think I read in ON4UN's book
"Low Band DXing", that the radial requirements for a half-wave vertical
were substantial. That is, you need a better radial system for a 1/2 wave
vertical than you do for a 1/4 wave (or shorter) vertical
>
> 73,
> Mike Waters
> W0BTU
This often repeated idea about half wave verticals needing many radials
has a grain (a very small grain) of truth in it. If you want to get
the theoretical 2 dB of gain that a half wave vertical has vs
a quarter wave vertical, you may indeed need a big ground screen.
But in actual tests, I have found that a half wave vertical with
essentially zero radials is as good as a quarter wave vertical
with a bunch of radials. See: http://www.n6rk.com/ground.pdf
I have been using 1/2 wave verticals w/o radials for years in
many locations and they have always worked fine for me despite
their seeming "impossibility".
Rick N6RK
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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