bandsaunter/packaging/saunterbrowse.1
The Dust Council 3d7f76118e Read the pictures, the aircraft, the meters and the sensors
Hexadecimal is a true answer to "what did that say" and not a useful one.
This is the work of turning the rest of what a receiver hears into
something a person can read, and most of it is pictures.

PICTURES

Three of the things on the air are images rather than sounds, and all three
arrive as the audio a scan already records:

  SSTV     14.230 and 144.5 MHz   Martin M1/M2, Scottie S1/S2/DX, Robot 36/72
  APT      137-138 MHz            the NOAA weather satellites
  HF fax   2-20 MHz, sideband     the marine weather charts

Each is written from its published specification, and the generators used to
test them are written from the same specification without reference to the
decoders -- so a picture that comes back matching the one that went in is
evidence about the format.  Every SSTV mode reproduces its published line
time exactly, which is worth failing a test over: a line a few milliseconds
long walks the picture off the screen inside ten lines.  Against synthetic
transmissions at 30 dB SNR, SSTV is 96-98% of pixels exact, APT correlates
at 0.97 and fax at 0.998; all three still read at 6-12 dB.

None of the three is guessed at, and that is what makes it safe to try them
on every recording.  SSTV needs its VIS header, APT needs both line syncs at
the right distance from each other, fax needs the phasing signal.  No false
pictures in 295 attempts over noise, tones, speech and swept whistles.

Two things had to be got right beyond the arithmetic.  A band-pass does not
switch between two tones, it slides between them, so every edge is measured
at the midpoint of the slide rather than at the first sample past a
threshold -- the earlier version was reading the coarse search stride back
as the edge and shifting Martin M1 sideways by a whole colour bar.  And a
picture now keeps its capture whatever the content check made of it: a
satellite is a steady tone with a wobble on it and SSTV is a whistle, so
both were being discarded as "no signal content" having already been
recognised.

PNG is written here rather than pulled in from Pillow.  A scanner that
cannot start because an imaging library is missing is worse than one that
cannot draw.

saunterbrowse marks a picture in the list, gives its path in full -- wrapped
rather than cut off, because half a path opens nothing -- and moves or
deletes the PNGs with the recording.  o prints the picture's path, not the
audio's.

GRIB is not a modulation and is not pretended to be one.  It is the format
weather models are published in and it travels by satellite link and by
e-mail; where a decoded byte stream begins with its magic number it is
named, and that is all.

AIRCRAFT

`bandsaunter adsb` parks the receiver on 1090 MHz and reads Mode S extended
squitter: address, callsign, altitude, position, speed.  A command of its
own because a megabit a second will not go through a channel twelve and a
half kilohertz wide.  Every frame carries a 24-bit checksum so there is no
threshold anywhere in it -- with one trap, which is that a frame of all
zeros satisfies that checksum and silence is exactly that.  Positions round
trip exactly through compact position reporting, and a pair straddling a
longitude-zone boundary is refused rather than resolved against two grids.

METERS AND SENSORS

Itron ERT utility meters on 900 MHz and AcuRite weather sensors on 433 MHz
are named rather than reported as hex, and neither is believed without its
own checksum -- BCH(255,239) for the meter, a checksum and four parity bits
for the sensor.  Both are implemented from published descriptions and
checked against frames built from the same descriptions, which proves the
framing and the arithmetic and is not the same as having held a meter.

HEX INTO WORDS

Everything else that decodes to bits now gets its fields named where the
shape is standard, its text read out where there is text, and its bytes laid
out in groups with the printable characters beside them.

The text search is where the care went, because printability is not
evidence.  Forty framings of each packet, and seven-bit values printable
three in four, meant a bar set on printability called 64% of random payloads
text.  Real text is nearly all one case where random letters are half and
half, two fifths vowels where random is a fifth, and mostly alphanumeric
where random draws punctuation one time in four.  Together: under 0.5%,
measured in the suite.

CALLSIGNS

The licensed address is recorded in full -- the street, not merely the town
-- and goes into the KML with everything else.  US amateur records are
public by law and carry it; holding it and not saying so is worse than
either showing it or not asking, and --no-lookup asks for none of it.

Also here: Morse is decoded again from the whole recording where the capture
was made in cw mode.  The first pass works from the classifier's buffer,
which holds a few seconds -- enough to say "this is Morse", not enough to
catch a callsign whole between two word gaps, so a beacon repeating every
eight seconds through an eight-second window was never identified.

And classify._psk_order took the logarithm of zero on a silent block.

1318 tests, up from 1161.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016PsWPTweCT6pwxKngvVxcg
2026-08-29 19:38:37 -07:00

446 lines
15 KiB
Groff

.\" Generated by packaging/make-browse-man.py -- do not edit by hand.
.TH SAUNTERBROWSE 1 "2026-08-29" "bandsaunter 2026-08-29_03" "User Commands"
.SH NAME
saunterbrowse \- read and listen to what a bandsaunter scan collected
.SH SYNOPSIS
.B saunterbrowse
.RI [ DIRECTORY ]
.RB [ \-\-sort
.IR ORDER ]
.RB [ \-\-filter
.IR TEXT ]
.RB [ \-\-player
.IR CMD ]
.RB [ \-\-list ]
.RB [ \-\-callsigns ]
.RB [ \-\-kml
.RI [ FILE ]]
.RB [ \-\-no\-lookup ]
.SH DESCRIPTION
A scan leaves a directory of recordings. Beside each one is a JSON file
holding what the classifier made of it, and for speech a transcript of what
was said. Reading that by hand means opening files one at a time and guessing
which are worth playing.
.PP
.B saunterbrowse
shows them as a list you move through with the arrow keys. The transcript of
whichever recording is highlighted fills the top of the screen, because that
is the part you actually want to read; underneath it are the identification,
the bands the frequency falls in, and the list itself. Pressing Enter plays
the recording.
.PP
With no
.I DIRECTORY
it opens the one the scanner writes to, taken from your saved settings, so it
normally needs no arguments at all.
.PP
Recordings can also be dealt with as they are read. A key files one into
saved/, investigate/ and noise/, another deletes it outright, and another locks its frequency
out of every later scan. Nothing else is written: without one of those keys
the browser only reads.
.SH KEYS
.TP
.B "Up Down k j"
Move through the recordings.
.TP
.B "PgUp PgDn"
A screenful at a time.
.TP
.B "Home End"
The first and the last.
.TP
.B Enter
Play the highlighted recording. Playing a second one stops the first: two
players talking over each other is worse than either alone.
.TP
.B Space
Stop playing. With nothing playing, it starts, like Enter.
.TP
.B t
Read the whole transcript full screen, scrolling with the arrow keys. Useful
for a long net, where the panel at the top can only show the first few lines
\[em] it says so when there is more.
.TP
.B /
Filter. What you type is matched against the frequency, the filename, the
identification and
.I everything that was said,
so "was the repeater mentioned" is a question you can ask directly. Enter
accepts, Escape clears.
.TP
.B s
Cycle the order: time, frequency, duration.
.TP
.B r
Re-read the directory. A scan running in another window is still writing to
it, and this picks up what has arrived since.
.TP
.B o
Print the highlighted recording's path and quit, for piping into something
else.
.TP
.B "S I N"
File the highlighted recording into saved/, investigate/ and noise/ respectively \[em] the
recording and every sidecar written beside it, together. See
.B MANAGING THE RECORDINGS
below.
.TP
.B u
Put the last recording that was filed back where it came from. One level
only, and a delete cannot be undone this way.
.TP
.B d
Delete the highlighted recording and its sidecars for good. It asks first:
this is the one key here that cannot be taken back.
.TP
.B m
Lock the highlighted recording's frequency out, so that no later scan stops
on it again. The frequency is written into your saved settings, the same list
.BR bandsaunter (1)
maintains, and takes effect on the next scan \[em] a scan already running read
its settings when it started.
.TP
.B "? h"
The list of keys, and which audio player was found.
.TP
.B q
Quit. With a filter in force, Escape clears the filter first.
.SH OPTIONS
.TP
.BI DIRECTORY
Where the recordings are. Defaults to the scanner's output directory, or to
.B $BANDSAUNTER_OUTPUT
when that is set.
.TP
.BI \-\-sort " ORDER"
Start in this order: time, frequency, duration. Time is newest first; duration is longest
first.
.TP
.BI \-\-filter " TEXT"
Start with only the recordings matching this, exactly as if it had been typed
at the
.B /
prompt.
.TP
.BI \-\-player " CMD"
The command used to play a recording. The path is appended as its last
argument. By default the first of these that is installed is used:
pw-play, paplay, aplay, play, ffplay, mpv.
.TP
.B \-\-callsigns
Print every callsign heard in the directory, with the licence it belongs to
and where and when it was heard, then exit.
.TP
.BI \-\-kml " [FILE]"
Write a map of where the stations heard in this directory are licensed, and
exit. Without a filename it writes
.I callsigns.kml
in the recordings directory \[em] the same file a scan writes, so a map built
this way is continued by the next scan rather than duplicated. See
.B THE MAP
below.
.TP
.B \-\-no\-lookup
Do not contact the licence database. Callsigns are still found and still
described from their prefix; only the name and address are missing.
.TP
.B \-\-list
Print one line per recording and exit, without drawing anything. This is what
to use over a pipe, in a script, or anywhere there is no terminal.
.TP
.B \-V ", " \-\-version
Print the version and exit.
.SH SOUND
Playback is handed to whichever player is installed rather than done in the
program: the recordings are ordinary WAV files, every desktop already has
something that plays them, and a browser that cannot start is worse than one
that cannot play. If none is found, everything else still works and the
message says which packages would fix it.
.PP
Over ssh there is usually no sound server at the far end. The browser and its
transcripts work regardless; only Enter has nothing to do.
.SH DETECTED CALLSIGNS
Under the transcript, headed
.BR "DETECTED CALLSIGNS:" ,
is every callsign heard in it, with the name and location on the licence.
.PP
Finding them is not a matter of one regular expression over the text as
written. A speech recogniser is poor at callsigns \[em] they are not words,
they are said one character at a time \[em] so it breaks them wherever the
speaker paused and writes the phonetic alphabet down verbatim. It also joins
the words back up, hyphenates them, spells them the way they sounded, and
writes down the hesitation in the middle. "KU 0W", "K7 RA",
"kilo uniform zero whiskey", "Whiskey\-One\-Alpha\-Whiskey",
"WhiskeyOneAlphaWhiskey", "wiskey one alfa whisky" and
"whiskey one alpha, uh, whiskey" are all one callsign each, and all of them
are read back correctly.
.PP
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
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.
.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
.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
.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.
.PP
.B \-\-callsigns
prints every callsign in the directory, who it belongs to, and each frequency
and time it was heard on, then exits.
.PP
US amateur licence records are public by law, and include the street the
licence was issued to, not merely the town. That is what is shown, and what
is written into the map: holding it and not saying so would be worse than
either showing it or not asking for it.
.B \-\-no\-lookup
asks for none of it.
.SH THE MAP
A licence says where its holder is, so a list of callsigns is also a map. The
scanner writes one as it runs and
.B \-\-kml
builds one from recordings already on disk; both write the same file, so
either can carry on from the other.
.PP
Each station is one placemark, not one per transmission: hearing the same
repeater twenty times in an evening is one station, and twenty pins stacked
on the same rooftop would say less than one. The pin holds the callsign, the
licensee, the town, the grid square, and every frequency and time it was
heard on, so clicking it answers "when did I hear this, and where on the
dial".
.PP
The file is added to rather than replaced. A scan on Tuesday continues the
map Monday made, which over a few weeks turns into a picture of what your
aerial can actually reach.
.PP
Where the licence carries no coordinates the grid square is used instead, and
the placemark says so, because a grid square is kilometres across where a
licensed address is a street. A callsign with no licence on file at all is
still recorded, in a folder named
.IR "no location on file" ,
switched off by default: that a station was heard is worth keeping even when
nothing says where it was.
.PP
KML is the format Google Earth uses.
.BR qgis (1),
.BR marble (1)
and OsmAnd open it too, and it is XML, so a scan interrupted halfway through
leaves a file that still opens.
.SH MANAGING THE RECORDINGS
A night's scan leaves hundreds of files, most of which are worth nothing and
a few of which are the reason you left it running. Deciding which is which is
what this program is for, and the keys that act on a recording are meant to
be pressed once each, going down the list.
.TP
.B S
Into
.IR saved /
\[em] keep this one.
.TP
.B I
Into
.IR investigate /
\[em] come back to this one.
.TP
.B N
Into
.IR noise /
\[em] not a signal worth keeping.
.PP
Each of these moves the whole capture \[em] the
.IR .wav ,
the JSON sidecar, the raw IQ where it was kept, the transcript and the decoded
data \[em] because a recording in one directory and its transcript in another
is a pair nothing will ever put back together. If the move cannot be finished,
whatever has already moved is put back: half a capture in each of two places
is worse than none moved at all.
.PP
The subdirectories are ordinary directories inside the recordings directory,
so a scan writing there never looks into them and never lists what is in
them. To read what is in one, point the browser at it:
.IP
.EX
saunterbrowse ~/bandsaunter/saved
.EE
.PP
.B u
puts the last one filed back. One step, not a history: it exists so that a
mistyped key costs nothing, not so that an evening's sorting can be unwound.
.PP
.B d
deletes instead, and asks first, because nothing puts that back.
.PP
.B m
is the other half of the same job. A birdie, a pager transmitter or a data
link that fills the recordings directory night after night is not a recording
problem, it is a scanning problem, and this writes the frequency into the
lock-out list in your settings file. The width comes from the
.B lockout_width
setting, so a lock-out is a channel rather than a single point. Locking out a
frequency does not delete what has already been recorded on it \[em] the two
keys are separate on purpose, and pressing both is the usual thing to do.
.SH PICTURES
Some recordings are not sounds. Slow-scan television, the NOAA weather
satellites and the shortwave weather fax stations all send images as audio,
and
.BR bandsaunter (1)
writes what it decodes as a PNG beside the recording.
.PP
Those are marked in the list by what they are \[em] "SSTV Martin M1 320x256" \[em]
and the panel at the top of the screen gives the path of the file in full,
wrapped rather than cut off, because a terminal cannot draw a PNG and saying
exactly what to open is the most useful thing left. A weather satellite pass
has three files: the whole frame, and each of the satellite's two sensors on
its own.
.PP
.B o
prints the picture's path rather than the recording's, for piping into an
image viewer:
.IP
.EX
saunterbrowse \-\-filter sstv \-\-list
xdg\-open "$(saunterbrowse)"
.EE
.PP
Filing a recording moves its pictures with it, and deleting one deletes them.
.SH CALLSIGNS IN MORSE
Most stations on the air never say a word. A repeater, a beacon or an
unattended transmitter sends its callsign in Morse and stops, and what it
sent takes the place of the transcript at the top of the screen, with the
licence it belongs to underneath exactly as for speech. It is searchable with
.B /
like anything else.
.PP
Only the part of it that was not cut in half is looked at for a callsign. A
capture opens when the squelch does, which is partway through a word as often
as not, and what is left of that word can read as a whole one:
.I K1AA
caught halfway through is
.IR K1A ,
which belongs to somebody else.
.BR bandsaunter (1)
describes how that is decided. The full text is shown either way.
.SH DECODED DATA
Where a capture carried data rather than speech, what was decoded takes the
place of the transcript at the top of the screen: the kind of packet, and then
the message. A pager's text, an APRS position report, or the bits and hex of a
remote control. It is searchable with
.B /
like anything else, so "which page mentioned engine 4" is a question that can
be asked here.
.PP
The text comes from the
.I _data.txt
beside the recording, or from the sidecar where there is none.
.BR bandsaunter (1)
describes how it is decoded and what has to be true before a decode is
believed.
.SH TRANSCRIPTS
A transcript appears only where a recogniser produced one, which means the
capture was judged to be speech and
.B bandsaunter\-transcribe
was installed at the time. Where there is none, the panel says which of the
several reasons applies \[em] Morse, data, a bare carrier, or speech that was
never offered to a recogniser \[em] because those want different things done
about them.
.PP
Two places can hold the text: the JSON sidecar records what was recognised
during the scan, and the
.I _transcription.txt
beside the recording is what a later re\-run wrote. The file wins, being the
more recent of the two.
.SH FILES
.TP
.I ~/bandsaunter/
Where recordings are written, unless the saved settings say otherwise.
.TP
.IR frequency \-\- date _ time \- modulation .wav
A recording.
.TP
.IR ... .json
Its measurements and identification.
.TP
.IR ... _transcription.txt
What was said, where a recogniser heard speech.
.TP
.IR ... _data.txt
What was decoded, where the capture carried data.
.TP
.IR saved /, investigate /, noise /
Where the filing keys move recordings to. Created on first use; a scan never
looks in them.
.TP
.I ~/.config/bandsaunter/config.yaml
The settings the
.B m
key writes a locked-out frequency into.
.SH ENVIRONMENT
.TP
.B BANDSAUNTER_OUTPUT
The directory to open, overriding the saved settings.
.SH EXAMPLES
.PP
.RS
.EX
saunterbrowse
.EE
.RE
.PP
Open the scanner's output directory.
.PP
.RS
.EX
saunterbrowse /mnt/recordings \-\-sort frequency
.EE
.RE
.PP
Browse somewhere else, grouped by channel rather than by time.
.PP
.RS
.EX
saunterbrowse \-\-list | grep \-i "mile marker"
.EE
.RE
.PP
Search the transcripts from a script.
.PP
.RS
.EX
saunterbrowse \-\-callsigns
.EE
.RE
.PP
Everyone who identified themselves, and where they were heard.
.PP
.RS
.EX
saunterbrowse \-\-kml ~/heard.kml
.EE
.RE
.PP
The same thing as a map, to open in Google Earth.
.SH EXIT STATUS
0 on a clean exit, 1 when the directory holds no recordings, 2 when it does
not exist or there is no terminal to draw on.
.SH SEE ALSO
.BR bandsaunter (1)
.SH BUGS
The list is read when the browser opens. Press
.B r
to pick up recordings a running scan has written since.