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Re: FM satellites (was: Re: SUNSAT OVER EUROPE)


Laura Halliday wrote:
> This may sound really off the wall, but if single-channel
> FM satellites work so poorly, why do people launch them?
The idea is that an FM bird is accessible to more users than a linear
transponder using SSB.  Theoretically, a person using an HT should have
access to the birds.  From experience, I can tell you it is possible to
work AO27 with a Yaesu FT50R and a dual band gain "ducky" type antenna. 
I've done it many times, from various locations.

The PROBLEM is that there aren't enough of these types of satellites. 
AO27 is the only bird available to NA users.  We have had 4 passes of
Sunsat since launch, but it looks like it will not be a reliable bird
for European/North American use.

What we need, and what I have proposed is a constellation of easy sats. 
20 or 30 easy birds will facilitate "regular" users, as well as newbies.

There should be a competition between the universities to come up with a
winning design.  A large cash award, and prestige will be the trophy. 
The winning team will blueprint the design for the other schools to
produce.  If we built 20 or 30, and had them located in every country
with launch capabilities, eventually we would be able to hitch enough
rides to have an entire constellation of these birds orbiting the globe.

>From an engineering perspective, the birds would be the size of
toasters, LEO, sun synchronous, and polar orbiting.  Each would carry a
digipeater, all on the same frequency, as well as a "bent pipe" mode J

All of the "bent pipe" repeaters would be on the same frequency pair,
but uniquely toned, so operators would not key multiple birds.  Each
would have a CW identifier after a certain period of receiver silence,
sort of a unique "roger beep" to identify which bird/tone an operator
was accessing.  All would also respond to a universal tone, so
wilderness users, search and rescue, and priority users could "key" ANY
bird overhead at the moment.

The digipeater would allow APRS traffic, as well as facilitate 2 way
packet exchanges between stations in the footprint.

Once the design is formalized, I'm sure the devices could be produced
for less than $4,000 US.  Being such a small hitchhiker, and with the
proper backing, such a project is practical, and will help breathe life
into the amateur satellite program, and amateur radio in general.  With
this "Millennium" project operational, and a fleet of flying toasters
circling the globe, world amateurs will once again claim their rightful
place as innovators, and new hams (as well as old) will be inclined to
become satellite operators.

Are you on the bus?

73, Mike in Fort Myers, FL

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