I have an antenna question for the reflector. On the
local repeater here, the general consensus is "Get a
horizontal loop for VHF, they will outperform yagis".
(I know better, but hey, I just report what I hear).
So here is my question-I have heard gain figures
attributed to loops, or to stacked loops, but I don't
understand how. If an antenna is truely
omnidirectional, where does the gain come from?
As I understand it, a beam gets its gain from focusing
its RF in the forward direction. It takes the
radiation that would go to the front and sides, and
compresses it into the forward direction instead-or
something like that. The gain comes because you lose
radiation in other directions. But if an antenna is
onmidirectional, it is not compressing the signal into
one direction more than the others. So how does it
get gain? The only idea that I can come up with is
that it must cut down on the vertical lobes, taking
the energy from several of the vertical lobes and
focusing it into one or two vertical lobes. It can't
do it in the horizontal plane, or then it wouldn't be
omnidirectional.
So am I even on the right track with this question or
thinking? As you can tell, the local club really
needs a good course in antenna fundamentals!
73s John NE0P
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