Invalid message packets

[KC1SRI]

Hi All!

New to APRS, and liking the app a lot so far.  I'm running into an issue, though, where my messages to other callsigns keep generating [Invalid message packet] errors on APRS.fi, and it appears the messages aren't being delivered. This happens when trying to send them via local and internet.  This doesn't seem to be an issue with messages to groups or to EMAIL— those go through and don't generate errors. Beaconing works without error as well.

Here's a few of the raw packets from APRS.fi:

2024-08-19 10:30:21 EDT: KC1SRI>APQTH1,K1FFK-1,WIDE1*,WIDE2-2,qAR,KC1QHG::kr1st    :Good morning friend!{01}
2024-08-19 10:30:22 EDT: KC1SRI>APQTH1,K1FFK-1,EKONCT*,WIDE2-1,qAO,WA1VIN::kr1st    :Good morning friend!<0x00>01} [Invalid message packet]
2024-08-19 10:34:15 EDT: KC1SRI>APQTH1,K1FFK-1,WIDE1*,WIDE2-2,qAR,KC1QHG::kr1st    :Good morning friend!{01}
2024-08-19 10:34:17 EDT: KC1SRI>APQTH1,K1FFK-1,WIDE1,EKONCT*,WIDE2,qAO,WA1VIN::kr1st    :Good morning friend!<0x00>01} [Invalid message packet]
2024-08-19 10:36:35 EDT: KC1SRI>APQTH1,K1FFK-1,WIDE1*,WIDE2-2,qAR,KC1QHG::KR1ST    :Good morning friend!{01}
2024-08-19 10:36:37 EDT: KC1SRI>APQTH1,K1FFK-1,WIDE1,EKONCT*,WIDE2,qAO,WA1VIN::KR1ST    :Good morning friend!<0x00>01} [Invalid message packet]
2024-08-19 10:49:11 EDT: KC1SRI>APQTH1,K1FFK-1,WIDE1*,WIDE2-2,qAR,KC1QHG::KR1ST    :Good morning friend!{01}
2024-08-19 10:49:14 EDT: KC1SRI>APQTH1,K1FFK-1,WIDE1,EKONCT*,WIDE2,qAO,WA1VIN::KR1ST    :Good morning friend!<0x00>01} [Invalid message packet]

2024-08-19 12:54:35 EDT: KC1SRI>APQTH1,K1FFK-1,WIDE1*,WIDE2-2,qAR,W1HS-11::w0rmt    :Trying this out. Maybe this packet won't get rejeceted?{01}
2024-08-19 12:54:36 EDT: KC1SRI>APQTH1,K1FFK-1,EKONCT*,WIDE2-1,qAO,WA1VIN::w0rmt    :Trying this out. Maybe this packet won't get rejeceted?<0x00>01} [Invalid message packet]
2024-08-19 13:10:45 EDT: KC1SRI>APQTH1,K1FFK-1,WIDE1*,WIDE2-2,qAR,KC1QHG::N6XE     :Good morning over there!{01}
2024-08-19 13:10:48 EDT: KC1SRI>APQTH1,K1FFK-1,WIDE1,EKONCT*,WIDE2,qAO,WA1VIN::N6XE     :Good morning over there!<0x00>01} [Invalid message packet]
2024-08-19 13:11:52 EDT: KC1SRI>APQTH1,K1FFK-1,WIDE1*,WIDE2-2,qAR,W1HS-11::N6XE     :Good morning over there!{01}
2024-08-19 13:11:54 EDT: KC1SRI>APQTH1,K1FFK-1,WIDE1,EKONCT*,WIDE2,qAO,WA1VIN::N6XE     :Good morning over there!<0x00>01} [Invalid message packet]

Thanks so much!

Joe KC1SRI

[Weston Bustraan]

So, it appears that the "Invalid message packets" have the byte that should be the last open curly bracket replaced with a null byte. On aprs.fi, the null byte is represented as <0x00>. It is also interesting that it appears that your messages are taking two different digipeater paths and when they do not pass through EKONCT, the messages seem fine. I am wondering if there is possibly something wrong with its software? From aprs.fi, it seems that it may be running a Kentronics KPC-3

I couldn't find any examples from aprs.fi that were sent via APRS-IS that have the <0x00> null byte in them.

The packets that get sent are all stored in "~/Library/Application Support/com.w8wjb.QTH/qth.sqlite3" in a SQLite database. If you would like to email me a copy of that file, I can open it up and see the data that was sent. You're welcome to crack it open too, if you're so inclined. The SQLite browser I recommend is SQLiteStudio. What I'd be looking for is whether those messages actually have a null byte in them or whether that was added by the digipeater. Digipeaters naturally modify packets, generally to add themselves to the path.

You could also try sending via APRS-IS only and see if the errors still appear; it uses the same code to construct the packet payload regardless of which type of connection it goes out over.

- Wes W8WJB