"SteveO232" wrote in message
...

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?




--
SteveO232

Hi Steve

I dont have the answer I think you are asking for. I have wondered how
to estimate the amount of signal loss to expect from my antenna when it is
elliptically polarized and receiving a circularly polarized signal.
I decided the math was too difficult for me and thought of it this way --
If my antenna is linearly polarized, it will be 3 dB down in sensitivity
from ideal.
If I am willing to assume that by making my Axial Ratio smaller, the
received signal will increase LINEARLY with the added orthogonal component,
an AR of .5 will be about 1.5 dB down from ideal.

I hope you get a better explanation of the desensititization related to
having an AR less than unity. I'd like to learn too.

Jerry KD6JDJ