[aprssig] PC2 PSK31 multiuser transponder
bruninga at usna.edu
Thu Aug 11 17:48:33 CDT 2005
I will generally not bother the APRSSIG list with
PCSAT2 announcements unless they directly
affect packet operation. I will assume everyone
that is interested in it will be on the amsat-bb.
But here is one I think everyone should know
about, since everyone has an FM rig and can
>>> Robert Bruninga 08/11/05 6:45 PM >>>
There is another big advantage of the multi-user
sharing PC2-PSK-31 transponder (with the FM
downlink) compared to any previous linear trans-
ponder. I was reminded of this by Peter Martinez,
the father of PSK-31.
Power hogging was always the problem with linear
transponders, but it will much less with this trans-
ponder because the entire downlink band is visible
to all users. Everyone sees exactly the same thing.
If your downlink signal is stronger than everyone
else's, everyone else including you will see who is
hogging the downlink AND you will see exactly your
impact on everyone else's signal. There will be no
excuse for excessive power.
On a free-floater satelilte (RAFT is our next one),
this mode could be almost completely self leveling.
But with all the blockage on ISS due to the huge
structures, each station will see large variations in
their signal and so it will take careful reaction to
keep one's signal reasonably constant.
de Wb4APR, Bob
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