[Skimmertalk] New Info on Callsign recognition

[N4ZR]

Following last week's discussion about the Japanese special callsign 
issued in honor of the upcoming G20 summit, I got an e-mail from Alex 
VE3NEA - as you probably know, all CW and RTTY callsign recognition for 
the RBN is done in his Skimmer software.  Alex confirmed my statements 
about the repetition matrix, requiring more reps from less common 
callsign patterns.  He also reminded me that the exact numbers of 
repetitions are determined by the Validation Level (from Normal to 
Aggressive), hence the "matrix."

In his e-mail, Alex said something I'd never heard before, so far as I 
know.  Rather than attempt to paraphrase, he's given me approval to 
quote him, so here goes:

"Valid callsigns whose patterns are not in the file are still spotted 
(except in the paranoid mode), they just require more repetitions. On 
the other hand, *invalid strings are not recognized as calls even if a 
pattern is added to the file [emphasis added]*

A valid callsign, from the Skimmer's point of view, is a string that 
starts with one of "@","@@","#@","#@@", followed by 1 to 4 digits, 
followed by 1 to 6 letters. Everything else is not recognized as a 
callsign. Therefore, "PC6A1A" is not considered a valid call by the 
Skimmer.

Your statement that the wild combinations of letters and digits, such as 
PC6J3E, are ignored by the Skimmer to prevent false decodings is totally 
correct.

Please note that many special callsigns, including 8N324A and AM70L, 
match the rule above, and the Skimmer gladly spots them."

I can't improve on that explanation!

-- 

73, Pete N4ZR
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