On 8/29/2020 7:16 PM, Richard (Rick) Karlquist wrote:
On 8/29/2020 5:44 PM, Dennis W0JX via TowerTalk wrote:
Dick Weber, K5IU, wrote a very informative article in the late 90's
which was published in Communications Quarterly. He argued that 1/4
wave long radials were the poorest length on could use. He strongly
recommended radial lengths of either 60-70 degrees (shortened) or 120
Now that I have had a chance to read the article, I still have a
couple of problems with it. On page 15, Dick states that the
driving impedance of all radials is purely reactive and goes
to zero at 1/4 wavelength. This doesn't agree with any modeling
I have done; there is always resistance. Secondly, I can't find
anywhere that Dick discusses why it is better to have one inductor
for all radials than individual inductors per radial. Or maybe
one inductor is just as good and is simpler. Did I miss something?
I am also not sure if this technique is mainly to fix verticals that
have to be installed next to existing towers that act as reflectors,
or if it is necessary for more "ideal" installations with no definite
causes of assymmetry. The argument that the inductor impedances
can't all be "zero" seems suspect.
It is also surprising that shortened radials don't have much
of a deleterious effect on bandwidth.
Rick N6RK
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