With Codec2 Talkie you can turn your Android phone into real VHF/UHF Walkie-Talkie (requires additional digital radio hardware/software modem). This minimalistic Android application is a Walkie-Talkie style digital voice frontend for your radio modem, which uses open source Codec2 for speech audio frame encoding/decoding.

It is mainly intended for DV experimentation with ultra low cost 3-8 dollar radio modems, such as LoRa and 15-25 dollar ESP32 board flavours with built-in LoRa module: T-Beam,