At 04:56 PM 9/20/2008, Nate Duehr wrote:
Tony's right: Of course polarity makes a difference. It's well proven physical science at this point in our RF history.
Indeed. :)
If the satellite is moving, rotating, and generally "messing up" the test, it's hard to always see the results of polarity changes -- mix in trying to do it by hand, and different people's tolerance for listening through noise, different receiver sensitivities, higher and lower gain antennas, and pretty soon -- the whole test is pretty non- objective.
Well, I had a pretty good way of determining polarisation. I used to hand rotate the antenna through 180+ degrees, and there WAS a definite peak and null, as you'd expect. This required frequent adjustments, as the polarisation would shift significantly during a pass.
Some people may say "not switching polarity works fine" and on a particular day, with a particular rig, antenna, satellite orientation or motion, and a different set of between the ears DSP filters (ears)
I can copy just about anything this side of white noise, but if I can improve the signal, I will. :)
73 de VK3JED http://vkradio.com