N6TR wrote:
> ... The two element quad is a great antenna, but as you add more
> elements, it becomes less clear that you are really getting much
> advantage. Maybe someone ... can explain why.
Yes, and that's why the "quagi" became so popular.
The two-element quad may be thought of as a stacked pair of two element
yagis with the element ends bent toward each other until they touch. The
stacking distance (1/4 wavelength) is much less than would be optimal, but
even so there is significant stacking gain around 1 or 1.5 dB. As you add
directors and lengthen the boom, the stacking distance of the equivalent
"pair of yagis" becomes much more seriously less than optimal. Long yagis
need much wider spacing than 2-element yagis in order to yield significant
gain over a single one. Hence, as you say, you don't really get much
advantage from using full-wave loop elements instead of half-wave linear
elements.
On the other hand, you certainly don't lose anything by using full-wave
loop elements. If they are mechanically convenient, it can be a good way
to go -- hence the popular UHF/microwave "loopers".
-- 73, Joe, K1JT
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