Hi Steve

Having absolutely nothing to do with your question but thought I'd
mention it...

Be aware that in a reflective/multipath environment you get a
polarization reversal. This makes for loss not unlike linear cross
polarization issues but only for the 1st, 3rd, 5th etc reflection.
Although I have never looked into it this would seem a useful feature
for data comms where out of sync/delayed signals might be a problem.

My first though to your actual question though would be to use a linear
antenna and rotate it whilst recording the signal level. Since however
you want to use a circular RX antenna you may be able to use the
reflection behaviour above to get some information. It appears however
that you want the maths, which I am also not really up to.

Cheers Bob VK2YQA

SteveO232 wrote:
I'm trying to throw together a helix antenna, similar to one shown
he
http://www.antenna-theory.com/antenn...ling/helix.php

I'm trying to get it to have circular polarization, but it deviates
away from that pretty quickly away from the main beam. If my receive
antenna is also circularly polarized, is there a way to estimate the
polarization mismatch loss based on how skewed the polarization is?
Like if its elliptically polarized, how can you figure out how much
power a circularly polarized antenna would receive from this?