Mode TETRA

TETRA: the public broadcast information of TETRA cells.

Group	Two-way radio
Default frequency	392.5 MHz
Default sample rate	2 Msps
In the mode list	Network info, 380 - 470 MHz

Step-by-step: Tutorial-TETRA

What TETRA is

TETRA is the digital trunked radio standard used by emergency services and organisations in many countries. OnAir shows network information only: what the base station broadcasts (network and colour code, location area, carriers, services, neighbours and whether encryption is used). It does not decode voice or messages.

Frequencies and settings

TETRA base station broadcast (ETSI EN 300 392-2: BSCH, BNCH, AACH, MCCH), 25 kHz channels.

Setting	Value
Start frequency	392.5 MHz
Tuning range of the mode table	136 to 960 MHz
Sample rate asked	2 Msps
Lowest working rate	200 ksps
Channel width	1.8 MHz

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 Network info, 380 - 470 MHz.

What OnAir shows

Network code, colour code, location area, carriers and duplex spacing, services, neighbour cells, whether encryption is used; scan over a span; receive only, nothing decrypted.

The mode's own tab has these screens: Cells, Neighbours, Carriers, Log. The other tabs (Overview, Receiver, Scan, History) are described on the Main window page.

Tips and caveats

• Network information only: no voice and no message decoding. Checked with generated signals and impairments; recordings of real signals welcome.
• TETRA traffic can be encrypted; OnAir never decrypts and decodes no voice or messages. It reads only what the base station broadcasts in the clear.
• Which radio: Usually yes for narrowband signals: 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.
• Try it without a radio: most modes include a built-in synthetic test signal, so you can open the screen and try the controls first.
• Receiving and the law: Receiving the public broadcast information of cells and base stations is legal in most countries; OnAir decrypts nothing and decodes no voice or messages. Check the rules where you live. See Legal.

Related pages

• Voice codecs
• All modes, Two-way radio
• Supported radios, Troubleshooting, FAQ
• More in Two-way radio: DMR, NXDN, P25, dPMR / PMR446, TETRAPOL