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9600 Baud PACSAT NEWBEE Observations



       Newbee Observations on the 9600 Baud Pacsats
 
   First, I am new to the 9600 baud Pacsats and some of these
observations may be just wrong.  WHere I error, please correct me.
Secondly, these observations are not intended to be confrontational, 
but simply to learn where we are in 1999 in the digital applications of
Amateur Satellites and where we are going.
 
   Admittedly, my interest in the amateur satellites is mostly for 
mobile, emergency, in-the-field, on the high seas and/or otherwise
operations *far* from any other terrestrial packet or the internet.
It appears to me that these are about the only applications where amateur
radio offers any true value over the worldwide internet.  With this
background, then, here is what I have learned as a newbee on the Pacsats:
 
1)  The PACSAT protocol is ideal for the bulk delivery of bulletins
and files of general interest.  It was an ideal solution for the
BBS forwarding requirements of the 1992/3 time frame before the
rise of the WEB and the demise of conventional packet.
 
2)  The PACSATS protocol is still an ideal internet replacement in 
those areas where there is no internet, or where it is too expensive
to use it for informal ham radio applications.  See #6 below.
 
3)  The PACSAT protocol only works for stations that are continuously
active on all passes, or at least most daily passes.  Stations that 
attempt to use the satellite less often, use it inefficiently since 
they have to individually request and download directories before 
they can even see if they have mail.
 
4)  There is no LIST-MY nor READ-MY commands on most birds.  Thus
the non-full time station has no way to find any messages.  He
has to request pages of directory listings and manually search for
any traffic for him.  This is inefficient for everyone.  See #2. 
 
5)  There is no real-time user-to-user communications capability.  
The satellites are just file servers.  They do not relay any real-
time  exchanges.  There is no such thing as a "QSO".
 
6)  95% of the users are not from the USA.  I attribute this to 
the low cost unlimited internet access in the USA and conversly
the pay-per-minute expense of the internet in most other countries.
 
7)  Interestingly, MOST of these stations are currently using the PACSAT
as a flying BBS for messaging instead of file transfer.  Most of thse
messages are very short.  Often less than 1K.

8)  The 9600 baud PACSATS CAN be received on an OMNI antenna during
high elevation passes, but not on horizon passes.
 
CONCLUSION #1:  It appears that the most significant factors that affect
the usage of the Pacsats is the internet and uplink congestion.  And that
due to differing internet implementations and amateur density in different
countries, its effects on amateur usage yield completely different results
in different areas.   
 
CONCLUSION #2:  The PACSATS are not usable for infrequent
come-and-go communications due to the half-implemented PACSAT Protocol.
 
CONCLUSION #3:  Conversly to these two conclusions, most of the 
traffic on the PACSATS are personal and very short QSO types of 
messages *in spite* of these obstacles.

CONCLUSION #4:  You CAN receive the Pacsats on an optimized rooftop
ONMI antenna for a few minutes during high elevation passes.  THus, you
COULD use the PACSAT mobile if there was a way to use it during these few
minute windows 10 times a day (5 birds at 2 overheads per day).
 
SUMMARY:  So it seems that the PACSATS serve a very vital function 
for providing worldwide internet type communications where it is not 
otherwise available, but otherwise, HAMS are still trying to use it
for just the fun of communicating even though it is not very efficient
to do it that way.
 
Maybe it is time to look closely at the mission of the PACSATS and 
to explore modifications or improvements for future implementations.
The most important of which is to complete the implementation of the
LIST-MY and READ-MY commands for the non-full time as-needed stations.
 
Again, this is not an attack on those who use the PACSAT daily and for
whom it provides a vital resource.  THis is a good mission and should
continue.  But it would be so easy to add just the simple READ-MY command
to make the satellite so much more valuable for so many more users....
*** In today's amateur radio ***
 
de WB4APR, Bob
 
Actually the PACSAT PROTOCOL has defined a very flexible EQUATION protocol
for "searching" the directories without having to have a copy.  Just
implementing this feature would solve all the problems and even allow
users to also just request directory entries for subjects of interest to
them.  I think it is time to do this or we may see the PACSAT protocol die
the death of conventional packet...




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