Hi Tom, KN6ZA
With only a 3db loss you can use a linear rec. antenna with no polarity switching, and avoid the large fading that would occur if the satellite was transmitting circular RHCP or LHCP........(but not linear as you stated)
On the other side if you receive linear and the satellite transmit linearly with opposite polarity you get more than 20dB of fading.
73" de
i8CVS Domenico
----- Original Message ----- From: "andrew abken" kn6za@hotmail.com To: tomdoyle1948@gmail.com; amsat-bb@amsat.org Sent: Saturday, August 04, 2012 10:45 PM Subject: [amsat-bb] Re: Antenna Polarization Technical Question
Tom,
I don't think any one who designs a system "wants" this to occur, but
as a function of overall system cost it is one of the unavoidable realities.
Its actually a great compromise, because with only a 3db loss you can
use a linear rec. antenna with no polarity switching, and avoid the large fading that would occur if the satellite was transmitting linear.
Now if you have the money to build a satellite that can point itself at
the receiving station at all times ie: geo synchronous:)$$$$ then that would be the cats meow;)
73 Andy
Not sure why anyone would want to maintain the orientation of the satellite in such a way that would cause the direction of circular polarization to change during the path. Perhaps people selling antenna circularity switches would like it but other than that I do not understand why it would be done. I am most likely missing something important.
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