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RE: Digipeaters in space



Bob, (et al)

I was one of the earlier people in the packet community in the Midwest US,
starting back in 1983.  I ran a packet BBS using MSYS on VHF and HF for
about 7 years (when my call was NT0P).  Although I haven't had the packet
station on in a while, I still have my equipment and intend to get it put
back together this summer.  This preface having been made, here's the point.

I'm scared to try packet/APRS on the satellites.  

I look at all the info on the digibirds and it seems all of them are going
to require yet more equipment or expertise that I don't have, don't know
where to get, or is/could be expensive.  There's Manchester, BPSK, AX.25,
Vancouver, TAPRS, 1200, 2400, 9600, etc. (or so it seems).  There's running
one baudrate and modulation up with another baudrate and modulation as the
downlink.  I thought most of these battles were waged and completed back in
the early 80's.  It seems to this one-time packet enthusiast that there
still is no standard and if I'm to make any sort of effort to operate on the
birds, it's going to take additional gear, study, and time to get it all
configured and running right.  Frankly, knowing all the time I spent running
the BBS for 7 years or more, it just plain, out and out, scares me away from
even attempting to try.  

Maybe I've gotten the wrong impression.  Maybe I'm just making excuses.
Maybe I just want a turn-key system.  Maybe the digi-satellite developers
need to (or possibly already have) re-think where they are going with the
systems they put into orbit.  

Please add your CONSTRUCTIVE comments to the thread.  Flames will be ignored
(been there, done that).

73 de N8AU, Jim in Raymore, MO



-----Original Message-----
From: Bob Bruninga [mailto:bruninga@usna.edu] 
Sent: Wednesday, April 30, 2003 10:08 AM
To: amsat-bb@AMSAT.Org
Cc: TAPR APRS SIG
Subject: [amsat-bb] Digipeaters in space


AX.25 UI Digipeating in the Amateur Satelite Service:

Since I began experimenting with HT digital messaging and status reporting
via satellite in the 1998 time frame, we have gone from 9 potentially
capable satellites down to none.

 SUNSAT (SO35) died
 KO-23 and KO-25 (both could be programmed to digipeat) are dead  UO-22 is
very iffy.  The ISS digipeater is off the air for months  SAPPHIRE has died.
OPAL was never very viable for this application.  SAFIR-M died  This weekend
PCsat has finally become un reliable

As of this week there are no reliable AX.25 digipeaters in space.  Over this
5 year period and seeing thousands of users on PCsat and via ISS, I still
have never gotten the impression that general UI digipeating is considered a
priority within the powers-that-be within the Amateur Satellite Service.
Yes, neat.  Fundamental.... no.

In fact, some even think that BBS style operations is the #1 priority for
packet in space.  Many still consider UI digipeating or APRS via satellite
as a small niche in the big scheme of things in the Amateur Satellite
Service and inconsequential.

I'm not sure where I am going with this email, because there are so
many-many diverse interests in HAM radio and Satellites, and everyone has
their own favorite interests, that a public debate accomplishes nothing
because there are always strong supporters of just about any mode and it
doesnt help one get the overall feel of the entire population.  Just the
loudest voices.

Maybe we don't hear from the AX.25-only-users who do not participate in
"satellite meetings and discussions" but who use the AX.25 satellite
digipeaters anyway as just a simple alternative to their terrestrial ones,
thus they are "under" represented in discussions?

Most surveys have focused on FM versus Analog, broadband verses narrowband,
New digital modes versus voice, etc.  And I fully support all these ideas,
but I also think we need a basic no-frills reliable generic underlying
bent-pipe digital communications mode in the Amateur Satellite Service that
is just always there.

Bottom line: I guess I'd like to see other Amateur satellites support the
secondary mission area of generic AX.25 digipeating on 145.825 just to give
us a lowest common denominator of generic digital communications that we can
count on.

One frequency (145.825), worldwide that HAM radio operators can always konw
that every few hours they can always communicate via satellite at 1200 baud
AX.25 using only a digital HT or portable anywhere on the globe. And they
dont need to know which satellite or to re-configure.  It just works and it
IS HAM radio...

Just thinking... no real mission here..  I'm glad to see UI digipeating
listed on the OSCAR-E list of secondary missions.

Bob, WB4APR

My web page on this subject has been:

  http://www.ew.usna.edu/~bruninga/astars.html

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