The RF321 is a 400.5 to 416.5 MHz radio. Campbell Scientific’s RF320-series narrowband UHF/VHF radio transceivers provide a long-distance telemetry option for communicating with remote measurement stations. Each radio includes a configured Ritron DTX-L radio, a mounting bracket, and a cable for connecting the radio to a radio modem. The different models vary by the frequency ranges they support.