Hi, All:
Steve asked the following:
Suppose you had a typical 5L 20M beam and the reflector fell off. What
is the real story as far as gain goes? Is it a drastic drop or what? Any
other
implications? I obviously don't do antenna modeling or I would have an
answer already. TIA.
--------------------
I ran a quick model using EZNEC. Here's what I found (assuming the Yagi at
70 feet above ground):
Model Gain (dBi) Z
Intact 14.94 22.2-j14.17
Broken 14.35 29.75-j22.1
I attached a PDF of the two patterns. There is not much difference in
forward gain. The interesting thing, however, is the degradation of the
F/B. Without the reflector, the F/B drops drastically. This mirrors the
experience I had when the reflector on a 4-element came off.
I think it was Dave Leeson who wrote something to the effect that "Yagis
just want to work." :-)
73, Bill, N5TU
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