[amsat-bb] AO16/LO19/IO26 APRS QSO Party, Results

[Bob Bruninga <bruninga@xxxxxxxxxxxxx>]

Satellite Buffs, and Digital Mobile operators,

Here is a quick summary of the APRS PACSAT QSO party conducted 4 Dec on
the three 1200 Baud PACSATS (I haven't finished the 3 Dec results yet).
During 5 passes over 400 UI packets were exchanged with at least 13
stations seen (even while 6 stations were logged on and downloading PACSAT
Protocol).  All downlink  packets were also linked into the worldwide
APRServe internet system.

APRS/UI STATIONS:  WB4APR, KB2WQM, KA2UPW, N8DEU, N5ZNL, K5QXJ, W4HFZ
PACSAT USERS:      W4MO, VE3FRH, VE2KAD, N8ULD, TG9IKE, K0RZ

One station, KA2UPW was using only a sound card on his PC to generate the
necessary MANCHESTER uplink.  N8DEU was using the WB4APR suggested $3
modified TAPR-2 TNC.  Others were using PACSAT TNC's and APRSdos, APRSplus
or WinAPRS and some with just terminal software.  The sound card method or
$3 mod makes it possible for anyone with a laptop and a 2m radio to uplink
while mobile.

With 3 satellites, ALL with uplinks on 145.90, (I was running only 20 
watts into a mobile WHIP antenna!) there is great potential
for providing mobile APRS POSITION/STATUS reporting for travelers via
satellite.  For example, the orbits of these birds gives the following
coverage pattern everywhere (local sun time):

DAY:  0930-1230 About 7 or 8 passes lasting 8-15 minutes each
NITE: 1930-0030 About 7 or 8 passes lasting 8-15 minutes each

Now all we need is someone to write the 1200 baud PSK downlink modem in
software for a sound card, and then these 9 year old satellites will be
VERY USABLE again... for amateur mobile digital communications.

NOTES:  The throughput of these 1200 baud satellites can be an order of
magnitude greater than terrestrial systems for several reasons:

   1) Each has 4 simultaneous receivers.  Thus even with only a 25%
      success rate on each uplink, the downlink can be kept full
   2) Since everyone hears the satelite direct, there need be only
      ONE digipeater hop, instead of the 3 or more duplications on
      the ground
   3) Since the satelite is crossband full duplex, the downlink is
      on 100% of the time instead of the maximum 50% for a simplex digi.

Thus, the birds could handle many hundreds of stations per pass per
satellite!  Right now, LO19 and IO26 are 100% dedicated to UI or APRS
digipeating.  AO16 is shared, since its PACSAT BBS is still functional and
usually has a few users on the weekends...

I will post the results on our TRAKNET web page so you can browse the
captured files if you are interested:

    http://web.usna.nadn.mil/~bruninga/traknet.html

P.S.  This test was conducted in conjunction with the annual APRS/GPS
tracking and communications support of the Naval Academy's running of
the Army/Navy game football from Annapolis to Philadelphia.

To those that participated, thanks for all your work!
de WB4APR, Bob


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