[aprssig] What is happening ?

Pete Loveall AE5PL Lists hamlists at ametx.com
Thu Jul 31 06:55:33 EDT 2008

Great web page!

The one common component for every dupe is being digipeated through ZL1BQE.  Start looking there for where the delays are introduced.  We have confirmed an issue with all models of the KPC-3/KPC-3+ in KISS mode that can introduce delays on the order of minutes like what is being seen here.  It appears the KPC-3/3+ TNCs have something similar to an "unchecked buffer overflow" on transmit that causes the receive side to get very confused causing these excessive delays.  If the KPC is left with the default of xon/xoff flow control (I know it shouldn't matter, but it does) before switching to KISS mode, the problem is even more apparent.  In every case of this being identified, replacement of the KPC with a different type of TNC caused the problem to be permanently removed.


Pete Loveall AE5PL
pete at ae5pl dot net

> -----Original Message-----
> From: Gerhard
> Sent: Thursday, July 31, 2008 2:29 AM
> To: TAPR APRS Mailing List
> Subject: Re: [aprssig] What is happening ?
> ZL1VFO gates duplicate packet to the APRS-IS with a delay of
> several minutes, so the are not caught by the default dupe time
> of 30 seconds.
> http://f5vag.eu/24h/ZL1BQE-9

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