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Geo Opportunity



Satellite designer alert...

The free ride to GEO I heard whispers of is real!
It would be as an attached payload.
THe main payload  has no attitude control.

THe time frame is 6 months.
ANy application must close the link to GEO assuming OMNI antennas.

I propose a PCSAT style packet transponder for TT&C.
and a linear transponder with 2m downlink and 10m and 70cm uplinks.

I will put together a propsal for a PCSAT type transponder for TT&C,
but I need someone else to look at the LINK budgets for the LINEAR
transponder.  Assume we would use one of the ultra-linear
AMPS used in the Cable TV industry for the 2m Linear downlink.

1) How much power is available from these amps??? (5w? 10w?)
2) Given that power, what will be the ground RX station required?
3) From that we determine how much solar panels we need.

Assume a 10m SSB uplink from an OMNI user with 25W transmit
ALso a UHF SSB uplink from what ever it takes.  Define it.

The CATV AMP would be grossly inefficient, but we can turn it off
most of the time and only turn it on for PRIME-TIME use in the
given hemisphere over which the satellite may be for any particular
time period.

Again, this ride to GEO is real, the ability to put something
together and get our foot in the door with only 6 mos to go
is the very hard part.  But I need numbers quickly!  No time
to develop the "ideal transponder", just something that works.

Remember the path loss to GEO is 20 dB worse than LEO, and the lack
of any gain antennas on the spacecraft lose another 10 dB or so.
We may have to put gain antennas on one side and then only plan
on using it SOME of the time.  It all depends on the details.

Serious responses please.  I dont have time to wade through a lot
of speculation...

I still have many more questions and this may all evaporate as I
learn more, but any effort someone puts into these questions will
serve us well the next time a drifter in the GEO graveyard
comes up...

de WB4APR, Bob


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