[amsat-bb] Re: Polarity questions

Tony Langdon vk3jed at gmail.com
Sat Sep 20 02:54:42 PDT 2008

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-

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

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