[amsat-bb] Re: D STAR

Gordon JC Pearce gordonjcp at gjcp.net
Tue Nov 12 01:54:43 PST 2013

On Tue, Nov 12, 2013 at 05:09:56PM +1100, Tony Langdon wrote:
> On 12/11/13 12:17 AM, Paul Stoetzer wrote:
> >An interesting idea would be trying a FreeDV QSO via satellite. I've made a
> >few QSOs with it on HF and it's an interesting mode.
> >
> >Obviously it's full duty-cycle, so any attempts should be limited to just a
> >few tests, but I'm sure it would work.
> I suspect you'd need computer Doppler correction with the FDMDV
> modem.  The high PAPR would limit the stress on a linear
> transponder.  The (yet to be finalised) VHF GMSK variant might be
> easier to handle from a Doppler point of view, though at a higher
> average power (since it's constant envelope like FM).

You could simulate doppler by injecting a suitable voltage ramp into your RIT control, making your HF rig "drift" in a known way.

Gordonjcp MM0YEQ

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