[hfsig] Is there anyone out there?
m5aka at yahoo.co.uk
Tue Oct 13 03:05:32 CDT 2009
Somethink I've been thinking of is a Digital Mode that could be used for QSOs through the Amateur Radio satellites.
Currently good old CW is the only effective digital mode for random two-way contacts.
The reason for this is Doppler shift.
For a satellite in a Low Earth Orbit the Doppler can between 10-30 Hz per second depending on the bands in use and orbital height.
Now I know you can use a PC to automically tune the Tx and Rx to compensate for Doppler but in practice most people seem to compensate for Doppler by manual tuning. Now this works fine for CW where it doesn't matter if a signal is 200 Hz off tune, you still tell what's being sent but currently none of the available Digital Modes can handle that.
73 Trevor M5AKA
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