snrLimit

The SNR (in dB) at or above which a packet sent with this modem preset can still be demodulated — i.e. the spreading-factor-determined demodulation floor. Signal quality should be judged relative to this limit, since the same SNR means very different things per preset: -15 dB is excellent on LongSlow (SF12) yet unusable on ShortFast (SF7).

Values follow the Semtech SF -> SNR floor (SF7 -7.5 dB, stepping -2.5 dB per spreading factor up to SF12 -20 dB). Unknown/unset presets fall back to ChannelOption.DEFAULT (LongFast).