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RE: RE: Geo Opportunity FM vs SSB



> Here is a new approach to the FM single channel versus SSB linear
> transponder tradeoff.  I think many discussions fail to  consider the
> widely different potential "applications".  For example, if 
> one does not
> bog down in weak signal argements and is concerned with passing
> meaningful information via a given channel comfortably, I 
> think FM wins.

It seems the question comes down to "What do you want to do with this
thing"?  If it's weak signal DX, transponders are the go.  However, if it's
nets/traffic handling, FM would seem to have a definite advantage.

There are other FM based systems which have similar contention issues as a
satellite would, namely the VoIP linked systems that span the globe these
days.  Once you hook up to a conference/reflector, you're part of a single
channel with global coverage (or at least accessible by a large number of
hams).  However, large nets can and _do_ succeed, as do even casual
ragchews.

A wide coverage FM satellite is a poor choice of channel for coverage of
high density areas such as cities.  However, it could be extremely useful
for covering sparsely populated parts of the globe.  You can always use
linking techniques to bring a big city or two online if you need that kind
of coverage.  FM is much easier to interface to terrestrial networks, which
will allow users in populated areas which are outside the footprint to
converse with remote users who are inside the footprint.

> So, it seems to me that for a given DC power available, that 
> it boils down
> to supporting multiple weak-sginal DX or supporting one 
> stronger, clearer
> FM quality signal.  The two have totally different 
> applications.   Chasing

Very true.  It's a choice between the two applications, and to me, chasing
DX on a bird that's in the sky pretty much all the time is akin to "chasing
DX" on IRLP or Echolink.  The only difference being the technical barrier
being a little higher, because the transponder is up so high.

> DX (ala UO-14) is a perfectly wrong way to use an FM transponder.

Agreed.  Over here, UO-14 gets a bit of a ragchew happening (often only 3 or
4 on the transponder), and that opens up remote areas for brief periods.
> 
> Operating a NET with a NET control like any useful traffic 
> handling net is
> an example of a RIGHT way to use a clear FM channel.

Even a self regulated ragchew is a much better use of the channel than the
DX chasing, because in a ragchew, everyone tends to be responsible for
managing contention.

> So there are lots of trades in this comparison...  the answer 
> is not as
> clear cut in my mind as some people seem to argue... 
> Remember, my design
> would have a private separate FM uplink channel for the NET 
> control which
> has priority over the "net" channel, so that he can maintain complete
> control.

Excellent idea.

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