[aprssig] APRS Message Callsign SPEC- Ambiguity

Robert Bruninga bruninga at usna.edu
Mon Apr 25 16:07:46 CDT 2016

There is an unintended ambiguity in the APRS SPEC regarding the addressee
in the APRS MESSAGE format.

It was intended that the TOCALL of any transmitted message could be sent to
ANY 9 character callsign field and this included mixed-case.  Although
TNC’s have historically forced callsigns to UPEPRCASE only, this is only a
limitation of TNC’s and was not intended to be a limitation of APRS.

STATION names, OBJECT names, ITEM names were intended to be a general 9
character mixed case field in APRS padded to 9 with spaces.

We just noticed that some radios do not allow sending an APRS message to a
mixed case address.

Unfortunately, the QIKCOM-2 satellite which does DTMF-to-Voice and
APRS-to-voice has a special message address of “QIKCOMsay” for all messages
it is expected to speak.  So some people will not be able to exercise this
text-to-voice messaging capability.

I wont make this mistake in any future satellite, but we are stuck with

SO, we might ought-to-identify all APRS radios and APRS clients that have
this uppercase-only restriction on MESSAGE Callsigns.

I can say the Kenwoods have it.  Others?

See http://aprs.org/aprs11.html and specifically, see:

See http://aprs.org/aprs11/aprs-names-and-spaces.txt

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