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Re: P3D information

Phil Karn wrote:

>  our prime
> concern must be to reduce the size, cost and hassle factor of the
> minimum usable amateur satellite ground antenna. That's *the* key to
> growing AMSAT beyond its present small niche.

Most postings to newsgroups etc. expressing displeasure seem to center
on hassle factor and availability.  Size and cost  aren't serious impediments
today as LEO satellites such as UO-14 can be accessed with a whip and  HT,
but  UO-14 scores low on the availability measure because it is essentially a
single channel system that gets heavily congested.

Certainly size and cost will become more important because path loss will be
greater at P3Ds orbital height, but I believe that availability will continue to be a
major consideration.  If the goal is to attract a large number of users then the
system needs to  have sufficient capacity to support the traffic load.   It will be
interesting to see what the QRM levels will be on P3D given its wide coverage area.

Do you have something in mind yet for link protocols that can be both flexible
and efficient?     Accommodating real time streams such as digitized voice and
multimedia will be a much greater challenge than accommodating relatively low
duty cycle data packets.

Ken  AC1H

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