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Old 16-Jan-2012, 1:32 AM   #9
Join Date: May 2011
Location: Central Illinois U.S.
Posts: 72
little update

I know a helical will get a gain boost of 3 Db if it's receiving a circular polarized signal (if both match direction of rotation wise).
Actually the boost is 3 dB only if both ends have an "axial ratio" (the ratio of horizontal to vertical signals) of 1 equal horizontal and vertical signals.

And a helical is equally sensitive to vertical and horizontal polarized signals (and all angles in between)
again the axial ratio affects how much.
But will a helical reject multipath or bounced or out of phase signals?
odd numbered reflections are blocked (attenuated) even numbered are not effected.
So single bounces are blocked and twice bounced are received.

edit: Found this recently

Last edited by ghz24; 22-Apr-2013 at 3:11 AM.
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