Mode NAVTEX

NAVTEX: safety messages for ships on 518 and 490 kHz.

Group	Maritime
Default frequency	0.518 MHz
Default sample rate	2 Msps
In the mode list	Ship warnings, 518 kHz

Step-by-step: Tutorial-NAVTEX

What NAVTEX is

NAVTEX is the maritime safety information service: navigational warnings and weather broadcast as text, mainly on 518 kHz.

Frequencies and settings

NAVTEX, DSC, weather fax.

Setting	Value
Start frequency	0.518 MHz
Tuning range of the mode table	0.1 to 174 MHz
Sample rate asked	2 Msps
Lowest working rate	250 ksps
Channel width	10 kHz

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 Ship warnings, 518 kHz.

What OnAir shows

Safety messages, distress and calling, fax pictures.

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

Tips and caveats

• Checked with generated signals and impairments; recordings of real signals welcome.
• Which radio: Only in direct-sampling mode, which OnAir offers in the radio settings, and the signal may be weak or absent. SDRplay and Airspy HF+ radios reach low frequencies directly.
• 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 ship and coast-station broadcasts is legal in many countries, with limits on using or passing on private traffic. OnAir is a receiver. Check the rules where you live. See Legal.

Related pages

• All modes, Maritime
• Supported radios, Troubleshooting, FAQ
• More in Maritime: AIS, VDES, DSC, Weather fax