Mode Orbcomm

Orbcomm satellite downlinks: satellite IDs, positions, channel assignments, messages.

Group	Satellite & navigation
Default frequency	137.25 MHz
Default sample rate	1 Msps
In the mode list	Satellites, 137 MHz

Step-by-step: Tutorial-Orbcomm

What Orbcomm is

Orbcomm is a satellite data network with downlinks near 137 MHz, used for tracking and telemetry of assets.

Frequencies and settings

Satellite data downlinks, 137.2 to 137.8 MHz (4800 bit/s SDPSK).

Setting	Value
Start frequency	137.25 MHz
Tuning range of the mode table	136 to 139 MHz
Sample rate asked	1 Msps
Lowest working rate	100 ksps
Channel width	0.6 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 Satellites, 137 MHz.

What OnAir shows

Two downlinks at once with Doppler tracking, satellites on the map from their ephemeris, packet log by type.

The mode's own tab has these screens: Map, Packets, Satellites, Signal. 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: 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 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-C, Inmarsat Aero, Iridium, Meteor-M LRPT, GOES HRIT, Elektro-L, QO-100, CubeSat telemetry, Globalstar