Dan - While I appreciate the simplicity of the Quad antenna and even referred
to N6NB's manifestation of a 144/222/432 in my post, I don't think that simply
stacking the antennas concentrically will work very well.
There will be a lot of interaction between the 144 and 432 elements, distorting
the pattern on 432 MHz. The N6NB triband Quad deals with this by moving the 432
elements forward so that the reflector of the 432 MHz quad is at the same
position as the 144 MHz director. I suspect that similar problems, although
perhaps not as bad will happen between the 6M and 2M loops.
Quads with lots of directors traditionally have never lived up to the
performance of a Yagi on the same boom length. I think it would be hard to
optimize the performance of a 12 element 432 MHz quad, particularly nested in a
144 MHz quad.
I am not sayign it can't be done, but I bet by the time you get done modeling
it, optimizing it, building it, and optimizing it again, it will look a lot
different than what you have proposed. But that is the fun of designing and
optimizing antennas. - Duffey
--
KK6MC
James Duffey
Cedar Crest NM
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