Put the APRS channel on the front page, and find it for you

The region was in the menu, in the receiver group, between the sample rate and
the invented channel.  That is the wrong place for it.  It is the setting that
decides whether anything is heard at all, and being on the wrong one sounds
exactly like having no aerial, so it does not belong a level down among the
things that make a working receiver work slightly better.

It is now on the front page of the APRS menu, named as well as numbered, and
so is the Listen line: "north-america 144.39 MHz" rather than "144.39 MHz",
because the number alone does not say whether it is the right one and the name
alone does not say what will be tuned.  A channel that is no region's says so
rather than claiming one.

The region and the frequency are separate settings -- somebody may want a
local packet network on neither -- which means they can be made to disagree.
Every place that chooses a region now goes through one function, so they
cannot.

And there is a search.  `bandsaunter aprs --find-channel`, or f in the menu,
listens on each region's channel in turn and prints what was on each, then
offers to use the busiest.  This answers the one question about APRS that
cannot be answered on any single frequency, because the answer *is* a
frequency: somebody who has just plugged a dongle in cannot tell a wrong
channel from a dead aerial, and that is worth a minute of listening rather
than an evening of doubt.

What it does not do is claim more than it found.  A quiet channel is not proof
of an empty one -- a fixed station beacons every half hour -- so what it finds
is traffic, and when every channel comes back silent it says that this is not
the same as an empty band and points at the aerial instead.

The invented channel now honours tuning, and only carries its stations on its
own frequency.  Without that the search would pass on a simulated band having
never searched anything, which is the kind of test that is worse than none.

Sixteen new tests against six deliberately broken builds.  The three that
searched a whole simulated band were doing the same expensive thing three
times over and now build their results directly, leaving one real end-to-end
search; that file went from nine and a half minutes to two.  Full suite 2612
passed.  Built as 2026-09-20_03.

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

packaging/bandsaunter.1

@@ -1,5 +1,5 @@
 .\" Generated by packaging/make-man.py -- do not edit by hand.
-.TH BANDSAUNTER 1 "2026-09-20" "bandsaunter 2026-09-20_02" "User Commands"
+.TH BANDSAUNTER 1 "2026-09-20" "bandsaunter 2026-09-20_03" "User Commands"
 .SH NAME
 bandsaunter \- scan, record and identify radio signals with an RTL-SDR
 .SH SYNOPSIS
@@ -2596,12 +2596,31 @@ already the name.
 .SS Which channel
 The frequency is agreed between amateurs rather than allocated, so it differs
 by region and there is no way to discover it from the air: on the wrong one
-there is silence, not a bad signal.
+there is silence, not a bad signal. That is the one fault that looks exactly
+like a dead aerial and is not, so it is the first thing to settle.
 .B \-\-region
 covers north-america (144.390), europe (144.800), australia (145.175), japan,
 brazil and thailand, and
 .B \-\-frequency
 takes a number for anything else.
+.PP
+.BI \-\-find\-channel " [SECONDS]"
+listens on each region's channel in turn \[em] twenty seconds each unless told
+otherwise \[em] and prints what was on each, then says which to use. It
+answers the one question about APRS that cannot be answered on any single
+frequency, because the answer is a frequency. A quiet channel is not proof of
+an empty one, a fixed station beaconing every half hour, so what it finds is
+traffic and what it misses is only the absence of traffic while it listened;
+it says as much when every channel comes back silent.
+.PP
+In the menus the channel is on the front page rather than a level down among
+the gain and the sample rate, being the setting that decides whether anything
+is heard at all.
+.B c
+lists the regions with their frequencies and also takes a number in megahertz
+for a channel that is no region's;
+.B f
+runs the search and offers to adopt whichever channel had the most on it.
 .SS What it reads
 Positions, uncompressed and compressed into thirteen characters of base-91;
 Mic-E, which every Kenwood and Yaesu mobile sends; weather, attached to a