Hear the short replies, and read the other kind of callsign

Two things, both found by measuring rather than by reading the code.

The voice-activity filter inside the recogniser is off. It was costing
words: across a night of land-mobile captures it dropped 5-15% of what
the same model finds without it -- 491 against 507, 339 against 384,
263 against 310 -- because a single-word over between two
transmissions looks to a VAD exactly like the noise it exists to
remove, and on a scanner those short replies are the ones worth
having.

Turning it off has a cost, and the cost is that Whisper hands back
"You" for five seconds of hiss as confidently as it hands back a
sentence. So the whole capture is now asked once whether anything in
it rises above its own noise. Digital silence measures 0.0 dB of
contrast and hiss at any level 0.7, while the quietest real capture of
that night measures 8.9 and most measure 10-27; the bar sits at 3, an
order of magnitude clear of both. It can veto a capture but never trim
one, which is the whole difference between it and the filter it
replaces.

The second thing: callsigns like WQVF960 were being missed entirely.
The shape being matched was the amateur one -- prefix, district digit,
suffix -- and everything else the FCC licenses is written the other
way round, the letters first and then the digits. On the GMRS and
business channels that is most of what is said: nine callsigns across
five transcripts of one evening went by unrecognised, and now do not.

The shape is written as the three allocations that exist rather than
as "letters then digits", which claims KN95, WD40 and KC135. Its
letters are checked against the word list even when they arrive as a
single token, which the amateur shape does not need -- no English word
has a digit in the middle of it, but "west 120" and "word 100" fit
this one exactly.

Lookups now fall back to hamdb.org when callook has nothing. Not a
spare copy: callook holds United States amateur licences only, so
DL1ABC and VE3ABC are INVALID there and resolve perfectly well from
the other. And a GMRS callsign is not looked up at all -- every
database reachable without an account is an amateur register, so
reporting WQVF960 as "unlisted" would blame the callsign for the
absence of a source.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016PsWPTweCT6pwxKngvVxcg

packaging/make-browse-man.py

@@ -216,27 +216,42 @@ A suffix is not part of the callsign. Nothing is joined across a slash, so
 .I W1AW/B
 is W1AW and not W1AWB, which belongs to nobody.
 .PP
+Two shapes are recognised, not one. An amateur callsign is a prefix, a
+district digit and a suffix \[em] W1AW, KU0W, 2E0ABC. Everything else the FCC
+licenses is called the other way round, the letters first and then the digits:
+WQVF960 is a GMRS licence and WXG204 an older Part 90 one. On the GMRS and
+business channels those are most of what is said.
+.PP
 False positives are the thing to avoid: a browser that invents callsigns is
 worse than one that finds none. So a run of words is only accepted when none
 of its parts is an ordinary English word \[em] "or 3. Can you open 4" fits the
 shape once the punctuation is gone, and is not a callsign \[em] while a single
 token said in one breath is trusted, because W1BOY is a perfectly good
-callsign.
+callsign. The GMRS shape is not given that trust: its letters are a run of
+two to four, which is the length of a short word, so "west 120" fits it
+exactly and a licence prefix never spells anything.
 .PP
-The lookup uses the FCC's own licence data, published at callook.info, which
-needs no account and no key. The callsign is the only thing sent, results are
-cached under
+The lookup uses the FCC's own licence data, published at callook.info, and
+falls back to hamdb.org; neither needs an account or a key. The second is not
+a spare copy of the first \[em] callook holds United States amateur licences
+only, so a German or Canadian callsign is INVALID there and known to the
+other, and a source that is down takes only itself with it. The callsign is
+the only thing sent, results are cached under
 .I ~/.cache/bandsaunter/
 so the same net is looked up once however many nights it is recorded, and a
 lookup never delays the display: the entry says "looking up" and fills itself
 in.
 .PP
+A GMRS or business callsign is not looked up at all, and says so rather than
+saying "unlisted". Every database reachable without an account is an amateur
+register and WQVF960 was never in one, so reporting it as missing would blame
+the callsign for the absence of a source.
+.PP
 .B \-\-no\-lookup
 contacts nothing at all. Callsigns are still found, and still described from
 their own structure \[em] the prefix is allocated by the ITU and the digit is
 the US licensing district, so a callsign says which country and which region
-it belongs to without any database. Outside the United States that is all
-there is; callook.info holds US licences only.
+it belongs to without any database.
 .PP
 .B \-\-callsigns
 prints every callsign in the directory, who it belongs to, and each frequency