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Re: FM Satellites (Millennium Project)



Hi John,

John Magliacane wrote:
> Why wait?  How about designing/building handheld equipment to work the
> existing analog LEO birds?  If FM is somewhat practical, just imagine how
> much better SSB would be.  Or how about giving ACSSB a whirl (using the
> pilot carrier and an AFC circuit to compensate for Doppler shift)?
That sounds like an excellent mode.  I think Motorola tried something
similar a number of years ago.  They superimposed a tone on the signal
so there was no clarification needed on the receive side; the
microprocessor tracked the tone and zero beat the signal.  SSB for
idiots, one field engineer called it.

> > Almost every ham I know has a 2 meter HT.  Very few I know delve into
> > microwave technology on a DIY basis.
> 
> And the HT is "FM only" because hams, as consumers, are given little
> or no choice by equipment manufacturers.  :-(
Spread spectrum would probably be the most efficient technology
currently in use. With the right algorithm in place, many operators
could share the same slice of spectrum.  I know the VLSI chips are
available, since they produce so many cordless phones using this
technology.

Is anybody experimenting with spread spectrum on the current stable of
birds?

Didn't one of the military academies send up a bird using spread
spectrum?  What ever came of that project?  Sure would be nice to read a
follow up in your weekly Space News.  If I remember correctly, they were
going to release the specs for the mode some time this year, and maybe
even a circuit diagram for a receiver.  Do you have any information
John?

> 
> > My easy sat proposal (or reasonable facsimile) will bring sat use to the
> > masses, not just to the technically advanced.
> 
> The "EZ" in "EZSAT" has to do with ground station equipment, not
> necessarily with the satellites themselves.  If portable, low-cost,
> "EZ" operations are truly desired, then maybe we should concentrate
> our efforts on ground station equipment that makes this dream a reality
> regardless of the types of satellites in orbit.
I sure do wish one of the rig manufacturers would make a SSB transceiver
in a small HT form factor.  I've been looking for a 2 meter SSB rig to
set up a mode J portable station, and not only are they too expensive,
but too big also.  I can listen to the mode J SSB birds with my AR-8000
scanner, but want to transmit.

I thank you for taking the time to respond, and brainstorm.  Your note
and others are exactly what I had hoped to stimulate.  I KNOW I don't
have all the answers, but know for sure collectively WE do!

I really look forward to reading Space News weekly John, keep up the
good work.

73, Mike in Fort Myers, FL




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