[aprssig] Invalid DMR / MMDVM items

Nick VA3NNW tapr at noseynick.com
Tue Mar 30 23:06:09 EDT 2021


I'm seeing rather notable numbers of these invalid Items - type ")" - in 
the last month, possibly began much earlier:

:)EB5BYP-DP!3825.78N/000-23.72rRNG0034 IPSC2-EA-RPTR MMDVM 439.1000 at -7.6 MHz
:)G4XTZ-DP!5131.62N/000-37.61rRNG0034 IPSC2-DVScotland MMDVM 433.4000 MHz
:)KD6WYK-DP!372449.20N/1220621rRNG0034 IPSC2-USA-MN2 MMDVM 438.5000 MHz
:)ZL4WPS-DP!17111.08N/04228.99rRNG0034 IPSC2-NewZealand MMDVM 144.5500 MHz
:)SV6NOB-DP!60000.00N/600000.0rRNG0034 IPSC2-Romania MMDVM 434.0510 at -0.0 MHz
:)G8SEZ-DP!5206.25N/000-22.50rRNG0034 IPSC2-DVScotland MMDVM 432.6625 MHz

Pattern seems to be:

CALL>APZDMR,QTH*,TCPIP*,qAU,T2BLAH  ... experimental DMR TOCALL, direct 
by TCPIP?
:)CALL-DP!  ... an item ")" called [CALL]-DP, always the same call as above
ddmm.mmN  ... a perfectly fair looking LATITUDE (BUT see below)
/  ... symbol table, but then instead of:
dddmm.mmE  ... we get a very broken LONGITUDE, and often no E or W
r  ... symbol "/r" is usually a repeater
RNGnnnn  ... probably perfectly good range?
IPSC2-SOMETHING MMDVM  ... a comment
433.3000 MHz  ... a semi-valid frequency

10% of all ">APZDMR ... MMDVM" packets have invalid longitudes, often 
000-nn.nn or sometimes other crazy stuff like 600000.0 - is that... 600 
degrees? or 6000? E or W?   :-D

Another 2% instead have bad latitude, EG 17111.08N (too many digits, 
and/or HOW FAR north anyway?!?) or 37-0.00S or 4272043200.00N 
(waaaaat?), 60000.00N, 99900.00N

According to most of the docs, the frequency is supposed to be at the 
BEGINNING of the comment, have no spaces, and have 3 decimal places, 
like .../123.4567WrFFF.FFFMHz but hey, fine for human-readable comment 
if you're not trying to follow aprs.org/localinfo.html or 
aprs.org/info/freqspec.txt or aprs.org/info/echo-irlp-win.txt I guess?

The "DMR" and "MMDVM" might implicate something like 
https://wires-x.uk/the-mmdvm-tutorial/ as being responsible?

Something we can / should get fixed? Or ignore it, treat it as just more 
QRM?

Cheers
Nick VA3NNW

-- 
"Nosey" Nick Waterman, VA3NNW/G7RZQ, K2 #5209.
use Std::Disclaimer;    sig at noseynick.net
It said "requires Windows 95 or better", so why won't it work on my Amiga?





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