Tutorial Digital voice DMR D STAR P25

OnAir shows who talks to whom; hearing the voice needs a codec library.

What you need

A radio that tunes the band of the system (for example 446 MHz for PMR446 DMR / dPMR, 144 or 430 MHz for amateur D-STAR and M17, 800 MHz for P25 in the US) and an antenna for it.

Steps

1. Choose the mode in group Two-way radio (DMR, NXDN, P25, dPMR / PMR446) or Amateur: voice and packet (D-STAR, M17).
2. Enter the frequency (defaults: DMR 446.10625, NXDN 446.10625, P25 851.0125, dPMR 446.103125, D-STAR 145.375, M17 433.475 MHz) and press Start.
3. Watch the screens: Now, Calls and Messages (DMR shows talkgroups, IDs and data); P25 also has Trunking and Talkgroups; NXDN a Site view; D-STAR a Map of D-PRS positions.
4. On the narrowband modes you can decode every signal in the visible span instead of only the tuned one (0.2.5).

Voice and the codecs

• OnAir never ships patented codecs. Voice modes need a library you install yourself: mbelib for the AMBE / IMBE modes (DMR, P25, NXDN, dPMR, D-STAR) and codec2 for FreeDV and M17. codec2 (LGPL) comes with OnAir; nothing to install for M17.
• The ? button next to the sound of each such mode shows whether the library was found, the file names and folders it looks for, an Open codecs folder button and Look again.
• Full instructions: Voice codecs.
• DMR voice through mbelib is unverified on real recordings.

Encryption and the law

Encrypted calls are only reported as encrypted; nothing is ever decrypted. In many countries it is illegal to intercept or disclose private radio communications. Follow the law where you live: see Legal.

Related: DMR, P25, NXDN, D-STAR, M17, TETRA.