OnAirTwo-way radio · Experimental
Decode DMR with an SDR
OnAir receives DMR. DMR two-slot digital voice and data, 12.5 kHz channel.
What DMR is
DMR is a digital two-way radio standard (TDMA, 12.5 kHz) used by businesses, public services and amateurs.
Frequencies and where it is used
Digital two-way radio.
In OnAir the tuning shortcut is Digital voice; you can enter any frequency your radio reaches.
What OnAir shows for DMR
Talkgroups, IDs and data (no voice).
This receiver is built from the published specification and checked end to end on simulated signals. It has had little or no testing on real transmissions yet, so reports and recordings on Discord are welcome.
Which radio you need
This is a shortwave mode, so the radio has to tune HF. An SDRplay, Airspy HF+ or an RTL-SDR in direct-sampling mode do that directly; with a HackRF an HF upconverter or a direct-sampling receiver is the usual route. A long wire or loop antenna matters more than the radio.
Questions about DMR
Can I decode DMR with an RTL-SDR?
An RTL-SDR can receive HF only in direct-sampling mode, which OnAir offers in its radio settings; results depend on the antenna. SDRplay and Airspy HF+ radios are better suited.
Is it legal to receive DMR?
In many countries it is illegal to intercept or disclose private radio communications. OnAir is a receiver: encrypted calls show up only as encrypted and are never decrypted, and voice needs a library you install yourself. Follow the law where you live.
Can I try DMR in OnAir without a radio?
Yes. Most modes include a built-in synthetic test signal, so you can open the screen and try the controls before you own a radio.
Try it without a radio
OnAir includes built-in synthetic test signals for most modes, so you can open this screen, see the layout and try the controls before you own a radio. The Tour button walks you through the app.