OnAirWeather & science · Experimental
Decode Radiosonde with an SDR
OnAir receives Radiosonde. Weather balloon radiosondes, 400 to 406 MHz (RS41, DFM, M10 and others).
What Radiosonde is
Radiosondes are small weather instruments carried by balloons, transmitting position and weather data near 400 to 406 MHz.
Frequencies and where it is used
Weather balloons, 400 – 406 MHz.
In OnAir the tuning shortcut is Balloons, 403 MHz; you can enter any frequency your radio reaches.
What OnAir shows for Radiosonde
Balloon tracks, altitude and weather data.
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
Any radio that tunes this range works. An RTL-SDR covers roughly 24 MHz to 1.7 GHz, and every other radio in the radio guide reaches it too. Antenna height and a clear view of the transmitter matter most.
Questions about Radiosonde
Can I decode Radiosonde with an RTL-SDR?
Usually yes for narrowband signals, as 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.
Is it legal to receive Radiosonde?
Receiving these signals is legal in most countries. OnAir is a receiver.
Can I try Radiosonde 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.