9GRadio is an open-source Android app for RTL-SDR dongles, released by Richard (9G5AR), focused on spectrum monitoring and multi-mode radio decoding. It supports AM, FM, NFM, WFM (including stereo), USB, LSB, CW, CWR, DSB, and raw IQ demodulation. On the digital side it covers APRS plus digital voice protocols (DMR, D-Star, YSF, DPMR, NXDN) and aircraft/marine/datalink modes (ADS-B, AIS, ACARS, RDS, multilateration). A standout feature is its built-in multilateration stack for transmitter geolocation — only two networked 9GRadio receivers are required, and the stack is advertised as protocol-agnostic, so any mode carrying a digital identity (AIS, ACARS, RDS, digital voice, etc.) can be localised. The APK and source are available on GitHub Releases; the app is not on Google Play.