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Re: Echo PL tone

> > Hi Drew and the list,
> >
> > I was just thinking about the QRM problem on the birds..
> >
> > Using mode U/v (the old mode B) instead of the V/u (mode J) might be a
> > solution to the QRM problem, but coordination with other birds may be
> > tricky?
> >
> > I've read that AO-10 used mode U/v with a 150 KHz passband! I'd imagine
> that
> > one FM bird downlink might be able to squeeze in with AO-10 gone...
> >
> > I would also imagine that the doppler effect would be less noticeable at
> 2m,
> > so the bird would be easier for beginners to receive?
> >
> Absolutely. The downlink is trivial to receive on Mode B FM from LEO, and
> interfering stations get dopplered out of the uplink quickly.  SO-35
> (Sunsat) was the absolute loudest thing I've ever heard from space. I
> it horizon to horizon on a 1/4 wave whip, with s9++ signals, and can't
> recall ever hearing a pirate or out of segment ham working terrestrial.
> Don't recall guys not hearing the downlink calling CQ either.
> There may be other issues involving coordination and ops in other
> all of which I'd be interested in hearing.
> I was told ECHO is mode J because Spacequest doesn't build VHF
> I guess thats as good a reason as any... Let's hope ECHO can run the
> downlink at a high enough power that some of the problems we've had with
> Mode J FM sats don't carry over to Echo.
> 73, Drew KO4MA

Mode B was killer!  The best part was everyone heard the bird so you didn't
have people calling and calling and not hearing their downlink.


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