determineSignalQuality
fun determineSignalQuality(snr: Float, modemPreset: Config.LoRaConfig.ModemPreset?): Quality(source)
Rates link quality from SNR relative to the active modem preset's demodulation floor (ModemPreset.snrLimit). A given SNR means different things per preset — e.g. -15 dB is excellent on LongSlow (SF12) but unusable on ShortFast (SF7) — so a fixed threshold mis-rates most presets.
RSSI is intentionally not considered: without the noise floor it cannot indicate whether a signal is demodulable, so SNR-versus-preset-limit is the meaningful measure (it is still shown to the user via Rssi). See #5446.
A null/unknown modemPreset falls back to the LongFast default limit.