Re: [amsat-bb] RHCP or LHCP or Linear

[Anthony Monteiro <aa2tx@xxxxxxxxxxxxxxxxxxxxxxxxxxx>]

At 05:10 PM 10/21/98 +0100, you wrote:

>Just how much attenuation and or change in signal strength do you get ? 
>And in particular on AO-27 what are the signal strength/polarization
>changes ?
>
>And, even if the satellite does turn upside down, does as several list
>members suggest, the polarization actually change from RHCP to LHCP, and if
>so why ?
>
>This is bothering me and I would like to know, thanks !
>

Hi Dave,
AO-27's antenna are linearly polarized. It doesn't matter if
the satellite is "upside-down" or "right-side-up" (or anything in-between!)
the polarization will still be linear.

The Faraday rotation through the earth's ionosphere will cause the
exact polarization angle at the ground station to change throughout 
the pass. As I recall, it generally goes through something like 3 
complete 360 degree rotations from horizon to
horizon on an overhead pass on the 70 cm downlink. and 12 times
or so on the 2 m up-link.

73,
Tony aa2tx@amsat.org

Tony AA2TX@amsat.org
Tinton Falls, NJ

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