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Re: FO-20 Haven't heard ?



Gene Harlan asked:
> I'm confused. On FO-20 and FO-29 are the frequencies reversed when
> they come down?

Yes.  All of the VHF/UHF linear transponder satellites are inverting
transponders (the RS birds are not).  That means a signal uplinked at the
lowest frequency in the uplink passband will come back down at the highest
frequency in the downlink passband.  It also means that on a SSB signal,
the sideband is flipped over.  In other words, if you uplink on LSB, it
will come down as USB (and that's the normal sidebands used).  The reason
for inverting the transponder is that the dopplers somewhat cancel. Since
doppler is proportional to frequency, it's far less of an issue at HF and
may well be why the RS birds don't invert.  Most of the activity is near
the midpoint of the transponder.

73
-----------------------
Jim Walls - K6CCC
k6ccc@amsat.org
Mobile Radio Operations
Southern California Edison Co.
Ofc:   626-302-8515   -   PAX   28-515
FAX:   626-302-7501   -   PAX   27-501


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