OnAirAviation · Experimental
Decode Airband with an SDR
OnAir receives Airband. Airband AM voice, 118 to 137 MHz: several 25 and 8.33 kHz channels at once.
What Airband is
The civil airband is AM voice between 118 and 137 MHz, with 25 kHz and 8.33 kHz channel spacing, used for air traffic control and airline operations.
Frequencies and where it is used
AM voice, 118 - 137 MHz.
In OnAir the tuning shortcut is AM voice, 118-137 MHz; you can enter any frequency your radio reaches.
What OnAir shows for Airband
Several 25 and 8.33 kHz channels at once: squelch, scan, priority, activity log.
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 is a shortwave mode, so the radio has to tune HF. An SDRplay, Airspy HF+ or an RTL-SDR in direct-sampling mode do that directly; with a HackRF an HF upconverter or a direct-sampling receiver is the usual route. A long wire or loop antenna matters more than the radio.
Questions about Airband
Can I decode Airband with an RTL-SDR?
An RTL-SDR can receive HF only in direct-sampling mode, which OnAir offers in its radio settings; results depend on the antenna. SDRplay and Airspy HF+ radios are better suited.
Is it legal to receive Airband?
Receiving aircraft broadcasts is legal in many countries, but some restrict listening to or using what you hear. OnAir is a receiver. Check the rules where you live.
Can I try Airband 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.