On Sat, Jul 26, 2014 at 10:24:15PM -0700, Phil Karn wrote:
On 07/22/2014 07:49 AM, wa4hfn@comcast.net wrote:
SSB/CW birds are the only way to go and if you build it they will come .
Think about what it would be like to tune for Doppler while working SSB through a LEO satellite on microwave.
Before you say "computer control", work out the effect of even a tiny error in your clock or orbital elements on a high elevation pass and remember that SSB has no carrier or pilot tone for closed-loop frequency tracking.
Sure, you could have a second receiver track the satellite's beacon. But if you're going to all that trouble, why not just have it track a single high speed data stream from the satellite, one that's much less affected by Doppler in the first place?
Exactly. It makes much more sense to go digital.
The crucial thing is *not* the complexity of the groundstation it is the lifetime of the satellite.
- 73 Diane VA3DB