[aprssig] What sets the max packet length for APRS

Andrew P. andrewemt at hotmail.com
Sun Dec 2 13:55:41 EST 2012

The currently assigned destination codes are maintained by Bob Bruninga in the webpage http://aprs.org/aprs11/tocalls.txt

At the present time, there are several usages of subsets of the APNxxx and APUxxx ranges, so you will need to select an unused sub-range of one of those and request Bob to reserve it for you.

Andrew Pavlin, KA2DDO
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: Bryan Hoyer <bhhoyer at gmail.com>
Date: Sun, 2 Dec 2012 17:09:50 
To: <aprssig at tapr.org>
Cc: <john at hays.org>
Subject: Re: [aprssig] What sets the max packet length for APRS

Thanks for clearing this up.

How do I reserve APNxxx or APUxxx for NW Digital Radios? i looked in APRS101 and see it isn't currently in use.


On Nov 10, 2012, at 4:21 PM, Robert Bruninga <bruninga at usna.edu <mailto:bruninga at usna.edu> > wrote:

The original texting APRS radio, the D7 can only display 45 bytes of Messages.  The D700 displays 64.
The VX8R etc I think displays 80 maybe.
Just remember, limiting to 45 charageceters will ALWAYS work and be seen by everyone.  Anything longer is risking miss-commmunication. 
But yes, they can be longer if you KNOW who you are sending to.  That is why the APxxxx identifies the type of radio in all packets, so we can see what their capabilities are.

From: aprssig-bounces at tapr.org <mailto:aprssig-bounces at tapr.org>  [mailto:aprssig-bounces at tapr.org <mailto:aprssig-bounces at tapr.org> ] On Behalf Of Bryan Hoyer
Sent: Saturday, November 10, 2012 11:22 AM
To: TAPR APRS Mailing List
Subject: [aprssig] What sets the max packet length for APRS
APRS1.01 states 67 characters for a message and up to 43 for a comment, yet I see packets twice that long on APRS.FI <http://APRS.FI> . This ones 109 after the :


KA8OAD-1 <http://aprs.fi/?c=raw&limit=&call=KA8OAD-1> >APU25N,K8YSE-1 <http://aprs.fi/?c=raw&limit=&call=K8YSE-1> ,WIDE1,K8UI-1 <http://aprs.fi/?c=raw&limit=&call=K8UI-1> ,WIDE2*,qAR,K8LI-1 <http://aprs.fi/?c=raw&limit=&call=K8LI-1> :@101613z4108.09N/08136.25W_190/004g005t057r000p020P020b10220h51FWX_http://pages.sssnet.com/kend <http://pages.sssnet.com/kend>  Fairlawn,OH


AX.25 says 256 bytes for the UI payload


A Tweet is 140 characters


An SMS is 160 characters


Is it just the display limit of some radios?


Just exploring the capabilities and limitations of APRS



Bryan Hoyer - K7UDR

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