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Add a manual page, and explain every setting in plain words

Browse source 
Every setting now carries a paragraph saying what it is in everyday terms
and why someone who does not already speak radio would turn it up, down,
on or off: what the squelch knob actually is, why automatic gain is a bad
idea for scanning, why a bias tee can damage equipment, why setting the
transcription language matters on noisy audio. The menus and
`config --describe` show it alongside the existing technical detail.

packaging/make-man.py generates bandsaunter(1) from that same table, so the
manual cannot document a setting the program lacks or miss one it has --
tests check both, that the page renders through groff without a single
warning, and that the guidance survives into the rendered output. Around
it are hand-written sections on the commands, entering frequencies, the
band plan, lock-outs, the keys during a scan, HF, single sideband, files,
environment variables and worked examples.

The .deb regenerates and installs it rather than shipping a copy, so an
installed manual always matches the installed program.

The README picks up what the last few commits added: the plain display as
a saved setting, what the settings tests now guarantee, and where to read
the manual before installing.

Version is the day's build: 2026-08-22_01.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
The Dust Council 2026-08-22 00:01:00 -07:00
parent 44c98b11e3
commit ba6c925351
8 changed files with 1711 additions and 4 deletions
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383
packaging/make-man.py Executable file
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#!/usr/bin/env python3
"""Generate the bandsaunter manual page from the settings table.
The settings are described in exactly one place -- bandsaunter/settings.py --
so the manual cannot drift from the program. Every setting appears here with
its command-line flag, its default, and the plain-language guidance that says
what it is and when someone would change it.
"""
import sys
from datetime import date
from pathlib import Path
sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
import bandsaunter # noqa: E402
from bandsaunter import settings as st # noqa: E402
from bandsaunter.config import ScanConfig # noqa: E402
def esc(text: str) -> str:
"""Escape for troff: a leading dot or apostrophe is a request."""
out = text.replace("\\", "\\e")
return "\n".join(("\\&" + ln if ln[:1] in (".", "'") else ln)
for ln in out.split("\n"))
def settings_section() -> list[str]:
out = []
defaults = ScanConfig()
for group in st.GROUPS:
out.append(f'.SS {esc(group)}')
for s in st.in_group(group):
flags = " ".join(s.flags)
if s.off_flags:
flags += " / " + " ".join(s.off_flags)
shown = st.format_value(s, getattr(defaults, s.key))
unit = f" ({s.unit})" if s.unit and s.kind not in ("bool",) else ""
out.append('.TP')
out.append(f'.B {esc(flags)}')
out.append(f'{esc(s.label)} \\[em] {esc(s.help)}{esc(unit)}.')
out.append('.br')
out.append(f'Setting name \\fB{esc(s.key)}\\fR, '
f'default \\fB{esc(shown)}\\fR.')
accepts = s.describe_range()
if accepts:
out.append('.br')
out.append(f'Accepts: {esc(accepts)}.')
if s.guidance:
# Indented to the entry it belongs to, not back out to the
# left margin, so an entry reads as one block.
out.append('.RS')
out.append('.PP')
out.append(esc(s.guidance))
out.append('.RE')
out.append('.PP')
return out
HEAD = r'''.\" Generated by packaging/make-man.py -- do not edit by hand.
.TH BANDSAUNTER 1 "{date}" "bandsaunter {version}" "User Commands"
.SH NAME
bandsaunter \- scan, record and identify radio signals with an RTL-SDR
.SH SYNOPSIS
.B bandsaunter
.RI [ command ]
.RI [ options ]
.br
.B bandsaunter scan
.BI \-r " RANGE"
.RI [ options ]
.br
.B bandsaunter
.RI "(no arguments: interactive menus)"
.SH DESCRIPTION
.B bandsaunter
sweeps any set of frequency ranges with an RTL-SDR receiver, stops on
signals that rise above the background noise, records them, and works out
what kind of signal each one was. Morse is decoded to text and speech can be
transcribed.
.PP
Ranges are given by hand or chosen from a built-in US band plan. There is no
limit on how many may be scanned at once.
.PP
Captures that turn out to be noise, static or interference are discarded
rather than saved, so what ends up on disk is transmissions rather than hiss.
This is the behaviour of
.B \-\-require\-signal
and it is on by default.
.PP
Every setting can be given as a command-line option, set in the menus, or
saved to a settings file; the three are the same list, described under
.B SETTINGS
below.
.SH COMMANDS
.TP
.B scan
Run a scan. Without
.B \-r
or
.B \-b
the interactive menus open instead.
.TP
.B bands
Browse the built-in US band plan: amateur, marine, aviation, public service,
business, railroad, GMRS/FRS, CB, ISM, weather, and more.
.TP
.B config
Show or change the saved settings.
.B "config KEY=VALUE"
sets one and saves it,
.B "config \-\-show"
prints them all,
.B "config \-\-describe KEY"
explains one in full, and
.B "config \-\-edit"
opens the menus.
.TP
.B transcribe
Transcribe existing recordings, or list which speech recognisers are
installed with
.BR \-\-engines .
.TP
.B devices
List attached receivers.
.TP
.B profiles
List saved profiles.
.TP
.B analyze
Identify a signal in an already-recorded file, or decode Morse from it.
.SH OPTIONS
.TP
.BI \-r " RANGE\fR, \fP" \-\-range " RANGE"
A frequency range to sweep, such as
.IR 144M\-148M .
Repeatable, and a comma-separated list is accepted. See
.B ENTERING FREQUENCIES
below.
.TP
.BI \-b " KEY\fR, \fP" \-\-band " KEY"
A band-plan preset, such as
.IR gmrs " or " marine\-vhf .
Repeatable.
.B bandsaunter bands
lists them.
.TP
.BI \-\-mode " MODE"
Force one demodulator for every range: nfm, wfm, am, usb, lsb, cw or raw.
Without this each range is demodulated according to what the signal turns out
to be, which is normally what you want.
.TP
.BI \-p " NAME\fR, \fP" \-\-profile " NAME"
Start from a saved profile instead of the saved default settings.
.TP
.BI \-\-save\-profile " NAME"
Save the settings this run would have used, under that name, and exit.
.TP
.B \-\-save
Save the settings this run would have used as the new defaults, and exit.
.TP
.B \-\-no\-config
Ignore the saved settings file and start from the built-in defaults.
.TP
.B \-\-simulate
Use a synthetic receiver instead of real hardware. Everything else behaves
normally, so the program can be tried out with no dongle attached.
.TP
.B \-\-dry\-run
Print the sweep plan \[em] every tuner step and how long a pass will take \[em]
and exit without receiving anything.
.TP
.B \-\-keep\-carriers
Also record steady unmodulated carriers, which are otherwise discarded as
having no content. Useful for beacon hunting or for tracking down a source of
interference.
.SH SETTINGS
Each of these can be given as a command-line option, changed in the menus
under
.BR "bandsaunter config" ,
or written into the settings file. The command line wins for one run; the
settings file is what every run starts from.
'''
TAIL = r'''.SH ENTERING FREQUENCIES
Frequencies may be written with a unit or without:
.IR 146.52M ", " "146.52 MHz" ", " 146520k ", " 146520000 .
A bare number under 10000 is read as megahertz, since that is how people
write frequencies.
.PP
A range is a pair:
.IR 144M\-148M ", " 144\-148M " (the unit carries over), " "144M to 148M" ", "
.IR 144M..148M .
A single frequency on its own is treated as a narrow range around it.
.PP
A step and a demodulator may be attached:
.I 144M\-148M/25k@nfm
sweeps in 25 kHz steps and demodulates narrowband FM.
.PP
Several may be given at once, separated by commas, and
.B \-r
may be repeated. There is no limit on how many ranges a scan may cover.
.SH BAND PLAN
.B bandsaunter bands
lists over a hundred presets from the US band plan, each carrying the right
step size and demodulator for that service, so
.B "\-b gmrs"
is enough to scan GMRS properly.
.PP
Presets that stand for several others expand automatically:
.I all\-cw
sweeps every Morse segment of every amateur band, and
.IR 2m\-complete ", " 70cm\-complete
and their like sweep a whole amateur band end to end rather than one segment
of it.
.SH LOCK-OUTS
Every receiving setup has a few frequencies not worth stopping on: a pager
transmitter down the road, a nearby data link, or a spurious signal the
receiver manufactures itself. Locking one out makes the scan skip it.
.PP
Pressing
.B l
during a scan locks out whatever is being received. Unless
.B \-\-no\-save\-lockouts
is given, it is written back to the settings file the run started from, so it
stays locked out on later runs. Only the lock-out list is written back \[em]
options given on the command line for a single run stay one-off.
.PP
Lock-outs can also be given directly, several at a time, as single
frequencies or as spans:
.PP
.RS
.EX
bandsaunter scan \-r 144M\-148M \-\-lockout "162.55M, 450M\-455M"
.EE
.RE
.PP
A single frequency is widened by
.BR \-\-lockout\-width ;
a span is used exactly as written.
.SH KEYS DURING A SCAN
.TP
.B q
Stop.
.TP
.B p
Pause and resume.
.TP
.B s
Abandon this recording and resume sweeping.
.TP
.B l
Lock out this frequency, now and in future runs.
.TP
.B "+ \fRand\fB \-"
Raise or lower the squelch threshold by 1 dB.
.SH OUTPUT
Recordings are named
.IR frequency \-\- date _ time \- modulation .wav ,
with the frequency padded to four digits so that an ordinary directory
listing sorts by frequency. Beside them are the run log, as JSON lines and as
CSV, and optionally a transcript per recording and the raw samples.
.PP
With
.B \-\-combine
every transmission on one frequency is appended to a single growing file for
that frequency, with a spoken date and time before each one, so a scan can be
played back as a recording of that channel rather than clicked through as
hundreds of fragments.
.SH HF RECEPTION
These receivers cannot normally tune below about 24 MHz. Below that they can
sample the antenna directly instead, which opens up shortwave: broadcast,
amateur HF, marine, aviation. It is switched on automatically when a scan
goes below 24 MHz. A direct connection to a suitable antenna is needed; the
whip supplied with most dongles will hear very little.
.SH SINGLE SIDEBAND
Single sideband is the one mode where tuning must be exact: its demodulator
is a filter that opens at the suppressed carrier, so tuning to the middle of
the voice discards its lower half and shifts the rest. bandsaunter measures
where the carrier is rather than assuming, and identifies upper from lower
sideband by which way the signal's energy leans, so
.B \-\-mode usb
is not needed. The frequency in the filename is the carrier \[em] the
frequency to dial into a radio.
.SH FILES
.TP
.I ~/.config/bandsaunter/config.yaml
The settings every run starts from.
.TP
.I ~/.config/bandsaunter/*.yaml
Named profiles.
.TP
.I ~/bandsaunter/
Where recordings, transcripts and logs are written, unless
.B \-\-output
says otherwise. Chosen on first run.
.TP
.I /etc/modprobe.d/blacklist-rtlsdr.conf
Written by the package to keep the DVB-T television driver from claiming the
receiver.
.SH ENVIRONMENT
.TP
.B BANDSAUNTER_CONFIG_DIR
Where settings and profiles live, instead of
.IR ~/.config/bandsaunter .
.TP
.B BANDSAUNTER_LIBRTLSDR
Path to a particular librtlsdr shared library, when the system one is not the
one wanted.
.TP
.B BANDSAUNTER_DRIVER_MESSAGES
Set to 1 to let the receiver driver print its own chatter, which is
suppressed by default because it draws over the live display.
.TP
.B BANDSAUNTER_VENDOR_DIR
Where a packaged speech recogniser is installed. Default
.IR /usr/lib/bandsaunter/vendor .
.TP
.B BANDSAUNTER_MODEL_DIR
Where packaged recognition models are installed. Default
.IR /usr/share/bandsaunter/models .
.TP
.B BANDSAUNTER_ENGINE_OUTPUT
Set to 1 to let the speech recogniser print its own progress.
.SH EXAMPLES
.TP
.B bandsaunter
Interactive menus: pick bands, change settings, start scanning.
.TP
.B bandsaunter scan \-b 2m \-b 70cm \-\-record 0 \-\-hang 6
Scan two amateur bands, following each conversation to its end and allowing
six seconds of silence between overs.
.TP
.B bandsaunter scan \-b marine\-vhf \-\-combine \-\-transcribe
Scan marine VHF, keeping one growing file per channel with spoken timestamps,
and write out what was said.
.TP
.B bandsaunter scan \-r 14.0M\-14.35M
Scan the 20 metre amateur band. Direct sampling switches on by itself.
.TP
.B bandsaunter scan \-b all\-cw \-\-decode\-morse
Sweep every Morse segment of every amateur band and decode what is heard.
.TP
.B bandsaunter scan \-b gmrs \-\-plain \-\-duration 3600
Scan GMRS for an hour with line-per-hit output, suitable for a log file or a
remote session.
.TP
.B bandsaunter config threshold_db=12
Raise the squelch threshold and save it as the new default.
.SH EXIT STATUS
0 on success, 1 for a bad option or an unusable configuration, 2 when the
receiver could not be opened.
.SH SEE ALSO
.BR rtl_test (1),
.BR rtl_sdr (1),
.BR espeak-ng (1)
.PP
The README shipped with the package covers the same ground at greater length,
including why the detection thresholds are what they are.
.SH BUGS
The DVB-T television driver claims these dongles on sight. If the receiver
cannot be opened, that is almost always why: the package blacklists the
driver on install, but the module must be unloaded once with
.B "rmmod dvb_usb_rtl28xxu"
or the dongle replugged.
'''
def main() -> int:
out = [HEAD.format(date=date.today().isoformat(),
version=bandsaunter.__version__)]
out += settings_section()
out.append(TAIL)
text = "\n".join(out)
text = text.replace("\n\n", "\n") # troff dislikes blank lines
target = Path(sys.argv[1] if len(sys.argv) > 1
else Path(__file__).parent / "bandsaunter.1")
target.write_text(text)
print(target)
return 0
if __name__ == "__main__":
raise SystemExit(main())