Bandwidth & Span

Demodulation Mode

Choose AM, NFM, or WFM on any radio. USB, LSB, and CW only appear for HF-capable hardware — SDRplay, AirspyHF, Fobos, or an RTL-SDR in direct-sampling mode. A standard Airspy (R2/Mini) is VHF/UHF-only and won’t show these modes; you’ll see a note explaining why if that’s the case.

Bandwidth

An editable box with mode-appropriate presets — you can pick one or type your own value. WFM and CW use a fixed filter width and can’t be adjusted. Switching demod modes resets bandwidth to a sensible default for that mode.

Span

Span sets how wide a slice of spectrum you’re viewing (and, on some hardware, actually capturing) — narrower spans give a tighter view with a lower noise floor (more sensitivity), wider spans give you more of a panoramic view at the cost of some sensitivity. The maximum span available depends on your specific radio.