Mode Inmarsat C

Inmarsat-C: satellite safety and news broadcasts, needs an L-band antenna.

Group	Satellite & navigation
Default frequency	1537.1 MHz
Default sample rate	2 Msps
In the mode list	EGC, L-band

Step-by-step: Tutorial-Inmarsat-C

What Inmarsat-C is

Inmarsat-C is a maritime satellite messaging system. Its broadcasts carry safety information (SafetyNET) and system messages.

Frequencies and settings

Maritime satellite broadcasts.

Setting	Value
Start frequency	1537.1 MHz
Tuning range of the mode table	1525 to 1559 MHz
Sample rate asked	2 Msps
Lowest working rate	250 ksps
Channel width	5 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 EGC, L-band.

What OnAir shows

Safety messages (SafetyNET) and system information.

The mode's own tab has these screens: Messages, Channel, System. 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: Probably not: an RTL-SDR tunes up to about 1.7 GHz. A HackRF (1 MHz to 6 GHz) or another wideband radio is the usual choice for this frequency range.
• 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 satellite downlinks is generally legal. Encrypted or spread content is not decoded, and voice codecs that are patented are not shipped with OnAir. See Legal.

Related pages

• All modes, Satellite & navigation
• Supported radios, Troubleshooting, FAQ
• More in Satellite & navigation: GNSS, Inmarsat Aero, Iridium, Meteor-M LRPT, GOES HRIT, Elektro-L, Orbcomm, QO-100, CubeSat telemetry, Globalstar