OnAirDecode Digital voice (auto) with an SDR
Digital voice, automatic: every system in the span found from the signal itself, with how sure.
- Group
- Two-way radio
- In the mode list
- DMR, P25, NXDN, D-STAR... automatic
What Digital voice (auto) is
Finds out which digital voice system is on the air (DMR, P25 phase 1 / 2, NXDN, D-STAR, dPMR, Yaesu Fusion, TETRA, M17, or analogue FM) from its frame syncs, lists every one in the captured span and switches to the decoder.
Frequencies and settings
OnAir takes any frequency you type; the numbers above are the mode's starting point and the range its table describes. In the app the shortcut label is DMR, P25, NXDN, D-STAR... automatic.
What OnAir shows
Finds out which digital voice system is on the air (DMR, P25 phase 1 / 2, NXDN, D-STAR, dPMR, Yaesu Fusion, TETRA, M17, or analogue FM) from its frame syncs, lists every one in the captured span and switches to the decoder.
Limits and what it was checked with
Checked with generated signals and impairments; recordings of real signals welcome.
Which radio you need
Any radio that tunes this range works. An RTL-SDR covers roughly 24 MHz to 1.7 GHz, and every other radio in the radio guide reaches it too. Antenna height and a clear view of the transmitter matter most.
Receiving and the law
Questions about Digital voice (auto)
Can I decode Digital voice (auto) with an RTL-SDR?
Usually yes for narrowband signals, as an RTL-SDR tunes roughly 24 MHz to 1.7 GHz at up to about 2.4 Msps. Wide signals such as TV channels need a faster radio, and OnAir says next to the source what the selected radio can do.
Is it legal to receive Digital voice (auto)?
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 Digital voice (auto) 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.