On Sun, 5 Apr 2009 15:29:43 EDT, RLVZ@aol.com wrote:
>
>RadioIR (below) states how EZNEC is not always accurate.
It is well known that EZNEC is not good at modeling antenna elements in close
contact with the earth.
>
>A few weeks ago, I posted an e-mail on how in dozens of side by side
>comparisons my single 40-m. 1/4 wave vertical near saltwater worked at least
>as
>well, if not better, than a new Cushcraft XM-240 Shorty-Forty at 90' in all
>directions the vertical looks over saltwater: Europe, Africa, and South
>America.
>Computer modeling indicated that the Shorty Forty should have about a 10dB
>advantage over the vertical with saltwater. (and the vertical has a minimal
>radial system: two 1/4 radials and a single 2" copper strap saltwater)
HANG ON A MINUTE! Salt water is a VERY special case. Verticals are VERY well
known to perform extremely well next to salt water, FAR better than they do
over
the more ordinary earth where most of us live.
>My hope is that more actual side by side antenna comparison information can
>be used to improve modeling accuracy.
My comments comparing verticals and dipoles are on the basis of BOTH NEC
modeling
and on the air comparisons during contests on a LOT of signals. I have yet to
find
any significant disagreement between NEC models and what happens on the air
with
MY antennas.
73,
Jim Brown K9YC
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