[aprssig] Draft Copy of Thesis on APRS

Curt Mills curt.we7u at gmail.com
Tue Dec 9 18:52:13 EST 2014

Section 5.1.2:  It's not clear from your wording that the character
limit for the source address does not include the SSID.  So it's up to
6 chars and then add on the SSID.

The 3-character minimum limit:  Isn't that for APRS, and not for
AX.25?  I don't remember any such limit for AX.25.  Been a while since
I read the spec!  I know the six-character limit is hard-coded in the
headers though.

The APRS "looser standard" for SSID can only be used on non-AX.25
links.  Maybe needs to be clearer in the text?  I know one can get it
from your current wording though.

Identification of digipeaters:  The FCC callsign doesn't have to
appear anywhere in the digipeated packets.  It does have to be sent
out every 10 minutes though (most do it at 9.5), but can be an
entirely separate AX.25 packet, not associated with APRS operation,
and with no digipeaters specified if one wishes, or as one guy on here
said, can be morse code (although that does take up time on the

Curt, WE7U

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