[amsat-bb] PCsat over Europe

[Bob Bruninga <bruninga@xxxxxxxx>]

G4FIP sent in a copy of a recent 3 Jan PCSAT high elevation pass over
Europe.  Here are the statistics on the total 67 packets he copied:

Station: Kenwood D700E with dual band "gain" vertical and 50' Mini-8 coax.

Packets:        5| 2|  | 1| 1| 6|11| 7|12|  | 5|  | 9| 9|
time: 10:xx ...57|58|59|00|01|02|03|04|05|06|07|08|09|10|...
Elevation:   0| 6|10|15|20|30|50|70|80|60|40|25|15|10| 5| 0

He estimates he hears about 50% of all packets with this marginal
setup.  A mobile with 10' of coax would do 2 dB better which is a lot
when you are dealing with satellites. Notice the number of packets
perfectly matches the antenna pattern of a 5/8ths wave gain antenna
with good gain at the horizon and above 45 degrees, but nulls in
the 10 to 40 degree range (half of the pass!  Thats why 5/8 mobile whips
do not do as well as a 19" vertical whip on a car roof).

Here is an analysis of the packets (notice this is weekday working hours)
which does seem to support his <50% reception estimate):

   6 PCSAT telemetry packets (44% success in the 13 minute pass)
   3 PCsat Bulletins         (probably a 33% success rate)
  58 packets originated by 9 different USERS

Of these 58 user packets from 9 users:

  16 were CONNECTS/RETRIES/BUSY'S (all caused by one station)
  22 were dupes of one other stn's posit (xmitted in bursts of 4 to 7)
  15 were reasonable packets from 7 reasonable operators

So most operators seemed reasonable although 2 consumed 65% of the channel
capacity.  Of the 7 resonable stations, all got in with multiple duplicate
positions and some appear to have been transmitting at a 30 sec rate or so
and achieving about a 45% success rate.  This suggests that the lower 1
per minute recommended rate would have worked quite well.

Here is an edited log summarizing the statistis:

10:57:37R PCSAT-1>:T#553,558,559,560,563,566 [6 successes in 13 mins]
11:02:38R PCSAT-1>:BULLETINS [2 LT1's 5 mins apart & One LT4]

10:57:18R I4xxx>CQ     : 4 APRS Posit copies in 8 seconds
11:03:12R I4xxx>CQ     : 7 APRS posit copies in 9 seconds
11:05:16R I4xxx>CQ     : 1 APRS POSIT
11:09:15R I4xxx>CQ     : 6 APRS POSIT copies in 3 seconds
11:10:12R I4xxx>CQ     : 4 APRS POSIT copies in 5 seconds
10:58:47R F4xxx>APRS   : 2 APRS Posits in 4 minutes
11:02:41R SQ5xxx>APU24H: 4 APRS POSITs in 5 mins [30 sec rate?]
11:02:46R PE2xxx>APRS  : 1 QSL... PE5xxx, I6xxx, F6xxx, SQ5xxx
10:58:03R I6xxx>CQ     : 3 separate UI packets
11:03:21R I6xxx>PE2xxx : 4 CONNECTED packets
11:04:20R I6xxx>[X,Y,Z]: 3 CONNECT Req to other stns
11:04:55R xxxxx>I6xxxI : 1 CONNECT ACK
11:04:59R I6xxx>PE2xxx,: 3 CONNECTED PACKETs (posits) in 1 min
11:05:08R I6xxx>PE2xxx,: 1 DISCONNECT
11:05:45R I6xxx>F6xxx, : 3 CONNECTED packets
11:07:21R I6xxx>I6xxx, : 1 CONNECT TO HIMSELF
11:09:05R I6xxx>OM     : 1 CONNECTED PACKET (posit)
11:05:47R xxxxx>I6xxx, : 2 DISCONNECT BUSY
11:05:04R F6xxx>APRSAT,: 1 APRS POSIT
11:05:35R SP6xxx>APRSAT: 4 COMPRESSED posits over 5 mins [30 sec rate?]
11:07:24R OE3xx>APU24M,: 2 APRS posits in 2 mins
11:10:08R DO3xxx>APRS, : 3 UI dupes in 45 seconds

Enjoy the bird!

de WB4APR@amsat.org, Bob

PCsat WEB  page     http://www.ew.usna.edu/~bruninga/pcsat.html
ISS-APRS FAQ:       http://www.ew.usna.edu/~bruninga/iss-faq.html
CUBESAT Designs     http://www.ew.usna.edu/~bruninga/cubesat.html
APRS LIVE pages     http://www.ew.usna.edu/~bruninga/aprs.html
APRS SATELLITES     http://www.ew.usna.edu/~bruninga/astars.html
MIM/Mic-E/Mic-Lite  http://www.toad.net/~wclement/bruninga/mic-lite.html






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