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Old July 20th 10, 02:10 PM posted to rec.radio.amateur.antenna
John Ferrell[_2_] John Ferrell[_2_] is offline
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First recorded activity by RadioBanter: May 2009
Posts: 101
Default Vertical antenna site tradeoff

On Mon, 19 Jul 2010 11:58:02 -0700 (PDT), Gsat
wrote:

On the yard around my house I have two possible spots where to erect a
multiband vertical, an HF6V.
On the first spot it is possible to lay down a symmetrical net of
radials as long as the antenna is tall, but the antenna will be close
to buildings on tree sides, at a distance about two to four times the
antenna height. Buildings in Italy are built by rinforced concrete
with a lot of steel inside, so I expect there will be some effect to
the antenna efficiency and radiation pattern.
On the second spot, the antenna can be more clear of buildings, but
the radials pattern is not symmetrical because il is limited to a
strip of land wide half the antenna height.
So now is my question: if a tradeoff must be made, what is more
important, to have an antenna on the clear or to have the best ground
radials system ?
A second question: is it possible to estimate the effect of ground
symmetry and of buildings presence on the antenna radiation pattern
using antenna simulation software like eznec ?

Thanks to all
Giovanni
IZ0SQZ


As usual, I cannot recall the source, but I read somewhere that the
symmetry and general layout of the radial field (buried radials) has
little effect on the radiation pattern. I do recall that I considered
the source credible.

I think there is a release of the NEC engine that supports ground
models but I don't know if that will answer this question.
Unfortunately it is priced beyond this hobbyist's budget.

There may be more than two choices. Don't overlook placing the antenna
between these two extremes.

John Ferrell W8CCW