[aprssig] APRS/Winlink puzzles

[Alex Carver]

> From: Greg D. 
> Subject: Re: [aprssig] APRS/Winlink puzzles
> To: <aprssig at tapr.org>
> Message-ID: <BLU133-W257529E2643850FC2E4F4BA9F90 at phx.gbl>
> Content-Type: text/plain; charset="windows-1252"
> 
> 
> Hi Lynn, et al,
> 
> Ok, so this is making more sense now, and also maybe a
> little less...
> 
> I looked again at the various bits of the puzzle, and I'm
> thinking now about the time problem.  It appears that
> my TH-D7 tried several widely separate times to send the
> message, as there are position reports that roughly
> correspond to the messages, at the times reported on
> aprs-is.  The rig was probably turned off in between,
> hence the large time gaps.
> 
> I'm thinking now that that my home station reacted to the
> first "ping" message sent out at 15:28z (8:28 local) by
> trying 4 times to send it to me here in California.  It
> wasn't seeing 4 separate messages on aprs-is after all, but
> rather doing several retries on just the first one because
> it never heard an ack.  (There is supposed to be an
> ack, isn't there?)  Note the messages are spaced 1
> minute, 2 minutes, and then 4 minutes apart.  Sounds
> like Bob's retry algorithm, no?

Your home station has no involvement in the sending or receiving of the data unless you have it configured as a bidirectional IGate.  It was only displaying things that it heard via APRS-IS.  Your D7 sent out four pings, Winlink tried to reply to each one.  The Xastir station simply noticed the messages pop back up on the APRS-IS and put them on the screen but did not do anything to send them to you.  The whole problem rests on the IGate that was close to you.  It did not, for whatever reason, send the responses back from APRS-IS onto RF so your D7 never heard them.  The D7 has a decay algorithm in it as well so it wasn't Xastir there either.



 
> So, then the next part of the puzzle....  Why weren't
> the other messages at 18:52z and 23:39z seen by my home
> station and copied to RF?  Did Xastir "learn" from the
> lack of Acks on the first message that I wasn't home? 
> (I'm running version 1.8.4, if that matters.  Yes, it's
> ancient, but the system just keeps running, so I leave it
> alone.)
> 
> And, a TH-D7 question...  Is there any way to "cancel"
> the re-try of a message from the D7?  It seems to have
> an annoying memory for incomplete things sometimes.

Yes, you go to the message list, highlight the message with the arrow and then press the Delete key.  I don't remember off the top of my head and I don't have my D7 handy but the letters "DEL" are silkscreened next to the button and the button is one of the few near the 4-way joypad.