Ken, To add to what others have said, real CP antennas are not really circular. They are elliptical, due to slight differences in the lengths of the phasing harnesses, lack of isolation between the two sets of elements, etc. That means, even for a perfect linear antenna, directly on the axis, that if you rotate it there will be preferred directions. As you get further from the axis, the ellipticity becomes more pronounced. Throw in the fact that the spacecraft antennas may not, due to interactions, be perfectly linear, and it is not unexpected to see what you are reporting. A helix antenna, while not switchable, will be more nearly CP but will normally have a slight variation.
73s, Alan WA4SCA _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
