OnAirSatellite & navigation · Experimental
Decode Globalstar with an SDR
OnAir receives Globalstar. Globalstar L-band downlink, 1610 - 1626.5 MHz: activity monitor only (receive only, the spread and encrypted content is not decoded): power, occupancy and Doppler of the 13 CDMA channels, an event log, and a pass overlay from the pass planner's TLEs.
What Globalstar is
Globalstar is a satellite phone and IoT network on L band. Its downlink is spread and encrypted, so OnAir only monitors activity, power and Doppler.
Frequencies and where it is used
Globalstar L-band downlink, 1610 - 1626.5 MHz, 13 CDMA channels of 1.23 MHz (receive only).
In OnAir the tuning shortcut is Satellites, 1.6 GHz; you can enter any frequency your radio reaches.
What OnAir shows for Globalstar
Activity monitor only: per-channel power, SNR, occupancy and Doppler (spectral centroid), a Doppler track against time with the pass planner's Globalstar satellites drawn over it, an event log. The downlink is spread and encrypted: nothing is decoded or decryptable.
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 Globalstar
Can I decode Globalstar 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 Globalstar?
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 Globalstar 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.