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Improving ground for a Vertical dipole worth it ?
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February 25th 05, 12:06 AM
Gene Fuller
Posts: n/a
Mark,
In the article quoted, Cebik was describing a half-wave "L" fed at the
corner; basically a bent half-wave dipole in an odd orientation.
He fully agrees that the more typical base-fed quarter-wave "L" would
benefit from radials.
73,
Gene
W4SZ
wrote:
KC1DI wrote:
Cebik says concerning the Inverted L antenna- which is similar to the
vertical Dipole that : "There is little evidence, despite the
vertical
position of one arm of the antenna, that the inverted-L would benefit
from a ground plane beneath the antenna. The actual low-angle gain of
the inverted-L will, however, vary with the quality of the soil in
the
region of reflection at a distance from the vertical arm. All
patterns
were taken over average soil, and soils that are either poor or
better
than average will tend to show a higher gain and lower take-off
angle,
at least on the fundamental frequency."
You might do well to read his articles at :
http://www.cebik.com/radio.html
He has quite a few dealing with the effects of different radial
systems
for vertical antennas.
I'd have to look at the articles later...But, as it is, I would
have to disagree with that. An inv-L is nothing like a 1/2 wave
vertical. He may be referring to an extended version, but normally,
an inv -L is a single wire loaded, 1/4 wave vertical,
and relies on the ground connection.
Max current is still at the base, and you can lose a lot to ground,
if it's poor. A longer 3/8, etc L would show lesser losses, but
radials would still help some.
MK
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