OnAirSatellite & navigation · Experimental
Decode Iridium with an SDR
OnAir receives Iridium. Iridium satellite bursts around 1622 MHz.
What Iridium is
Iridium is a constellation of 66 low-orbit satellites for satellite phones and data. Its L-band downlink near 1626 MHz carries pager messages, ring alerts and signalling.
Frequencies and where it is used
Satellite phone network.
In OnAir the tuning shortcut is Satellites, 1622 MHz; you can enter any frequency your radio reaches.
What OnAir shows for Iridium
Satellites on a map, pager messages, ring alerts.
This receiver is built from the published specification and checked end to end on simulated signals. It has had little or no testing on real transmissions yet, so reports and recordings on Discord are welcome.
Which radio you need
This mode sits at a high frequency, so check that your radio tunes it: a HackRF covers 1 MHz to 6 GHz, and RTL-SDR stops near 1.7 GHz. Some modes at these frequencies also need a fast radio (10 to 20 Msps) or a dish and an LNB.
Questions about Iridium
Can I decode Iridium with an RTL-SDR?
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.
Is it legal to receive Iridium?
Receiving satellite downlinks is generally legal. Encrypted or spread content is not decoded, and voice codecs that are patented are not shipped with OnAir.
Can I try Iridium in OnAir without a radio?
Yes. Most modes include a built-in synthetic test signal, so you can open the screen and try the controls before you own a radio.
Try it without a radio
OnAir includes built-in synthetic test signals for most modes, so you can open this screen, see the layout and try the controls before you own a radio. The Tour button walks you through the app.