tune_gain steps a device through its gain range, measuring the noise floor
and the strongest signal on the main spectrum at each, and applies the gain
where the signal stands furthest above the floor, or, on a quiet band, the
lowest gain at which the antenna's noise rather than the converter's sets
the floor, short of overload. It knows the RTL-SDR, HackRF, Airspy, LimeSDR,
PlutoSDR and USRP, and takes a gain key and values for anything else.
scan steps by the channel spacing usual for the mode unless told otherwise,
refuses modes on fixed frequencies, measures its threshold from the floor
rather than assuming one, and reports every active frequency rather than the
five strongest and where the scanner happened to park. Broadcast FM is
scanned on its 100 kHz raster whatever step is given, with only the local
peaks reported, and listen and scan give it a 512 kS/s baseband with the
channel clear of the DC spike. pager, sonde and dsc modes are added.
listen retunes a demodulator of the right type a previous call added rather
than replacing it, and applies the RTL-SDR receiver profile only to a device
set it created. set_spectrum_settings reads the settings back and says when
a value was rounded or an averaging mode is set with nothing to average over.
get_spectrum_data returns its power array, which the generated serialiser had
been dropping.
describe_settings covers the spectrum display, and list_docs and get_docs
serve the GUI's own pages: the spectrum, its markers, measurements and
calibration, the main spectrum window, audio, configurations, device user
arguments and the transverter dialog.
The receiving guide gains sections on scanning, where each mode's output
appears and how long to wait for it, judging signal levels, gain, the
frequencies asked for by name including the DAB blocks, and the RTL-SDR's
limits on HF.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Jon BenistonandClaude Fable 5.1