[aprssig] Final Web Page for AE0SS-11 and KC0YA-11 Balloon Launch Up -- APRS-IS Problems

Andrew Rich vk4tec at tech-software.net
Sat Mar 12 15:36:20 EST 2011

Could you please tell us

1. GPS
2. Power
3. TX power 
4. TX rate
5. PATH 

- Andrew VK4TEC - 
  ----- Original Message ----- 
  From: Stephen H. Smith 
  To: TAPR APRS Mailing List 
  Sent: Sunday, March 13, 2011 5:41 AM
  Subject: [aprssig] Final Web Page for AE0SS-11 and KC0YA-11 Balloon Launch Up -- APRS-IS Problems

  The dual launch announced earlier is over.   The final summary page is now on my website at:


  Major APRS-IS issues were evident  

  The actual downlink for APRS data from the balloons to the ground was on a private channel, that was then retransmitted on the usual 144.39 frequency to find it's way to igates and the APRS-IS (APRS Internet System).

  Tracking of these launches were marred by severely-delayed packets being injected into the APRS-IS.  This causes more recently reported data to be superseded by older data. The result is tracks that "hyper-jump" forward-backward-forward-backward.    In the case of  aerial vehicles like balloon, they also bounce up and down in  altitude.  (Note the "grass" of vertical jumps on the AE0SS-11 vertical profile graph, and the hiccups on both profiles.)  

  Delays in passing packets from the TNC to the attached computer is a known bug in KPC3+ TNCs operated in KISS mode connected to a computer.  The problem appears randomly after several days or weeks of operation, and can be cleared by issuing the RESET command to the TNC or by cycling it's power  OFF and then back ON.  This problem primarily affects home digi/igate  stations, since they typically use a computer-based setup.   It does not affect KPC3+ TNCs operating in stand-alone mode, as would be the case with most remotely located digipeaters.   

  Further,  these  launches were  marred by one or  more TNCs at digipeater or igate sites operating in PASSALL mode (a.k.a. "junque" mode). Numerous posits with impossible values were passed including elevations hundreds of feet  below sea level,   wild hyper-jumps 100s of miles at right-angles to the track path, and multiple corrupted versions of the two balloons' callsigns.

  The tracks were further confused by the balloon trackers apparently being powered up (for a test??) on the south side of the Denver metro area, before being taken to the launch site. Or were these posits sent before the GPS receivers achieved lock at the launch site?



  Stephen H. Smith    wa8lmf (at) aol.com 
  EchoLink Node:      WA8LMF  or 14400    [Think bottom of the 2M band]
  Skype:        WA8LMF
  Home Page:          http://wa8lmf.net

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