OnAirAmateur: digital · Experimental
Decode FT8 with an SDR
OnAir receives FT8. FT8 weak-signal contacts in 15 s slots, 14.074 MHz.
What FT8 is
FT8 is the most popular weak-signal digital mode among radio amateurs: 15-second slots, 8-FSK, and contacts that work well below the noise floor of voice.
Frequencies and where it is used
WSJT, 14.074 MHz.
In OnAir the tuning shortcut is WSJT, 14.074 MHz; you can enter any frequency your radio reaches.
What OnAir shows for FT8
FT8 weak-signal contacts in 15 s slots, 14.074 MHz.
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 FT8
Can I decode FT8 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 FT8?
Amateur radio signals are meant to be received. Receiving needs no licence in most countries; OnAir does not transmit.
Can I try FT8 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.