Re: [amsat-bb] Has anybody heard AO-10 lately ?

[Franklin Antonio <antonio@xxxxxxxxxxxx>]

At 01:36 PM 8/16/00 -0400, K5OE@aol.com wrote:
>I note AO-10 changes CP very quickly, whereas the LEOs like AO-27, FO-20, 
>and UO-14 change CP more gradually--you can hear the signal decrease over 
>a 10 second-or-so period and then you can change polarity to bring it 
>right back up.  I am not qualified to guess why this is so,

Various sidelobes, backlobe, etc of a CP antenna can have different 
polarization than the main lobe.  Some are right-hand and some are 
left-hand.  So if the spacecraft were rotating so that you move out of the 
main beam into a sidelobe, or from one sidelobe to another, or to the back 
lobe, you could experience the polarization changes you describe.  I think 
this is what is going on.

And yes, I also believe that polarization switching is a good thing.


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