[amsat-bb] Re: Polarity questions

Anthony Monteiro aa2tx at comcast.net
Sat Sep 20 04:56:52 PDT 2008

At 07:29 PM 9/19/2008, Clint Bradford wrote:
>  >>...I have to disagree with Clint...
>I just must be the luckiest S.O.B.(*) working AO-51, then...During
>demonstrations in front of folks, someone in the assemblage almost
>always asks about polarization. I twist the Arrow, and we all "hear"
>no difference in its strong, clean signal.
>Clint, K6LCS

Dear Clint and friends,

There is no luck involved. The UHF downlinks on AO-51 are
circularly polarized. You can twist your Arrow all you want
and you will not hear any difference, nor could you measure
any because there isn't any difference!

The cross-polarization loss from a circular TX antenna to a
linear RX antenna is a constant 3 dB regardless of the
actual linear polarization angle.

If you want to demonstrate polarization mismatch loss, use AO-27
(which is linear) with an Arrow.

Tony AA2TX


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