Perhaps I should have worded my question differently. I understand the concept of circular polarization and the reasons for it. What I should have asked was "Is one direction preferred over the other for working the satellites?". Thanks for all the excellent info and I think what I've learned is that the ability to switch between directions of polarization is best but RHCP is preferred if only one direction is available.
Domenico, thanks for the attachments. Good stuff which I had not seen before!
Tom - K0TW
If I'm building an antenna of circular polarization for use with the birds what determines if it should be LHCP or RHCP? I've read the ARRL Satellite Handbook and "sort of" searched the AMSAT-BB archives but found nothing about this question.
Thanks. Tom - K0TW