[aprssig] APRS Message Callsign SPEC- Ambiguity

Pete Loveall AE5PL Lists hamlists at ametx.com
Tue Apr 26 15:57:49 EDT 2016

Andrew, if the mixed-case service is a satellite (Bob's example), it can only ack via RF and it can't because AX.25 won't let it.  That is why I stated what I did.  Also, you get into a lot more obstacles when you try to use mixed-case for the packet origin callsign-SSID even on APRS-IS because most software will convert it to upper case thereby negating its usability with numbered messages.  In other words, stay away from lower case letters in numbered message addressees because the vast majority of software and radios won't process it correctly.

If what is being talked about is unnumbered messages, then acks and rejs are not an issue. Only the ability of the transmitting station to generate an unnumbered message with a mixed case "callsign" and the receiving software's ability to recognize such a message is required for Bob's request to succeed.  As discussed, however, even if the station (radio or software) has the ability to generate an unnumbered message (most radios do not, to my knowledge), most stations do not have the ability to generate a message addressee in mixed case.  While currently maintained software could be upgraded to support sending unnumbered messages with mixed case addressees, it must be assumed the majority of stations are not capable of such a transmission.

Hope this helps clarify both what is being asked for and where the obstacles exist.


Pete Loveall AE5PL
pete at ae5pl dot net

> -----Original Message-----
> From: spam8mybrain
> Sent: Tuesday, April 26, 2016 1:36 PM
> Subject: Re: [aprssig] APRS Message Callsign SPEC- Ambiguity
> One interesting point here is that RF stations wouldn't have to ack messages
> from this mixed-case service; the mixed-case service will have to ack messages
> from the RF ground station. So that's not an issue.
> The issue here is whether any given ground client can send to a mixed-case
> addressee.
> Andrew, KA2DDO
> author of YAAC

More information about the aprssig mailing list