All:
Once again, thanks for the informative replies on stacking 20/15/10 meter
monobanders on the same mast. I found Tom's (N6BT) article on Debugging an
Antenna Systems informative.
Tom mentions that when mounting monoband Yagi's on the same mast, anything
within 1/4 wavelength is a potential problem and it can greatly affect
front-to-back.
I think Tom used the word potential problem here because there can be
different configurations of Yagis and mast spacing.
With that said, it would seem the best starting point would be to model the
specific Yagi's to be stacked and mast size and go from there. The question
is, does anyone have the modeling know-how to present the before and after
front-to-back and gain figures for what I have in mind?
My intentions are to mount a four element 20 meter Yagi on 36 foot boom,
four element 15 meter Yagi on 27 foot boom and a four element 10 meter Yagi
on 15 foot boom -- the mast length is 20 feet.
The modeling would answer questions like does it pay to have one Yagi at 90
degrees or would boom length cause the coupling effect to worsen? Is the
"Chirstmas Tree" stacking the best way to go etc.
Thanks again..
73 Tony - KT2Q
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