Satgen 177      Digisat Organisation by GM4IHJ             15th August 92

In recent months several groups of digital satellite users have given
clear evidence of their preferences for certain satellite modes. From this
it is possible to see a little more clearly, how digital satellite usage
should develope in the near future if it is to meet operator aspirations.
The following is GM4IHJ's personal view . A viewpoint formulated after
talking to many digisat operators.

International Store and Forward Traffic . The 9600 bps satellites are
firmly established as leaders in this field. Almost all Gateway traffic is
now routed through Uosat 5 Oscar 22. Many of the 33+ gateways are using
automatic "hands off" software control. A secondary fall back in the event
of a problem with Uosat 5 , exists in Lusat Oscar 19. The Argentinian
satellite is clearly the best reserve , with hopefully Kitsat coming into
operation soon to reduce the heavy load on Uosat 5. Poor keying and
frequent problems are resulting in Pacsat Oscar 16 being unsuitable for
sustained operation in this role.

Personal Message Traffic via Store and Forward Satellites.  Uosat 5 and
Lusat, and , to a lesser extent Fuji Oscar 20 can provide a useful service
. With Fuji offering a simple route for newcomers to store and forward
techniques.

Digipeater Traffic.  This mode has been grossly neglected for nearly two
years, since Lusat and Pacsat were prematurely switched to binary
downlink. I suggest it would help if Pacsat Oscar 16 were to revert to a
digipeater role. If this happens we may get a chance to examine on Oscar
16 , the type of usage which may transfer to Arsene when that Digipeat
only system flies sometime in the next year. Arsene digital facilities
will be able to provide 3 or 4 station concurrent service over a whole
hemisphere of the earth. This will raise lots of questions.

Is it likely that many terrestrial bulletin boards will seek to use the
digipeater route to "opportunity " transfer of international traffic. Will
BBS's doing this be few and far between ? Will digipeating BBSs be one or
two per country, or more numerous ? Could Arsene be saturated if BBSs
decide to use it not only for long range international transfers , but
also, for short range transfers inside the BBS's national territory ? A
period of experiment using Pacsat Oscar 16 as a digipeater may give some
answers to these questions.

There are several other digital satellites in the pipe line. Most seem to
be 2400 bps or slower. Could these be devoted to digipeating for
individual users. Can we devise a gentle person's agreement , whereby some
digipeaters are open to BBS traffic but others are not. OR, do we try
allocating time slots ? BBS traffic permited on all digipeaters except
Arsene between 0000 local time and 0800 local ground station time ? Can we
try out any of these suggestions on Pacsat Oscar 16 and other low earth
orbit 2400 bps or slower digisat systems?
 
Can any of this be made to work ? Any and all, comments and suggestions
are welcome.  73 de John GM4IHJ @ GB7SAN