On Thu, 14 Aug 1997 11:57:41 -0500 sears@rell.com writes:
> A ground mounted 1/4wave vertical with the highly conductive
>Gumbo soil of North Texas really helps the far field pattern.
>
> Peter
> W5PS
======
I don't know about the soil conductivity in North Texas, but when I lived
in the Gulf coast area near Houston, I knew that the soil conductivity
there was extremely good. My shunt-fed tower there on 80m (which was
close to an electrical 1/2-wave) was an outstanding DX performer. The
same tower, shunt fed on 160m (close to an electrical 1/4-wave) was no
slouch, either.
When I moved here to the Mojave Desert over 20 years ago, I shunt-fed my
towers expecting the same results. For 160m it's still great, but a real
letdown on 80m, where it just barely holds its own in the pileups. This
is with an extensive ground radial system (96 long ones under each
tower), where in South Texas I had only about 30 short radials buried.
Since everything else was the same except for the soil conductivity, I
came to the conclusion that the far-field soil conductivity (where your
radials don't extend to) is a much more important factor with a 1/2-wave
vertical than it is with a 1/4-wave vertical. I've always assumed this
is because the 1/2-wave vertical radiates at a lower angle and there is
much greater attenuation at low angles due to poor far-field soil
conductivity as opposed to good far-field soil conductivity, regardless
of the radial (near-field) system used.
But, if it works, don't fix it.
73, de Earl, K6SE
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