SondeClosed beta
Join the SondeFox beta
SondeFox is in active development, and we're inviting a small group of radiosonde chasers to help us validate it in the field. The beta is closed and invite-based — request a slot by email, and we'll send you a build when one opens.
What the beta is
The main job of this beta is field validation: taking a decoder chain that already works on real hardware and proving it across many phones, cables, antennas, launch sites, and weather. That means the most valuable testers are people who can actually put an SDR in the air path of a sonde.
RF testers
To contribute reception reports you'll need an OTG-capable phone or tablet on Android 10+, an Airspy Mini or R2 (no RTL-SDR support), a 400–406 MHz antenna, and a USB-OTG cable — a powered hub is recommended. No root required.
Everyone else
No Airspy? Feedback on the UI, the docs, and this website is welcome from anyone. The browser demo runs the full five-screen interface with dummy telemetry — no install, no hardware.
What works today, what needs validation
We keep the status tiers honest — here is the short version. The full per-type breakdown lives in decoder support.
| Decoder | Status | Notes |
|---|---|---|
| RS41 (Vaisala) | Working | Validated end-to-end; live Airspy reception confirmed on real hardware. Wider field validation across sites and conditions is what this beta is for. |
| DFM06/09/17, M10/M20 | In validation | Implemented and tested on synthetic signals; awaiting over-the-air confirmation from testers. |
| iMet, LMS6, Meisei, MRZ, MTS01 | Roadmap | Planned. Not decodable yet — please don't expect them in beta builds. |
| Chirp monitor | Experimental | Off by default, PHY-only — no decryption of encrypted network traffic — and authorized signals only. See the chirp monitor page. |
Known beta gap: the Spectrum screen's tap-to-tune is designed but not wired up yet — tapping a peak doesn't retune the radio.
What we ask of testers
After each chase (or attempted chase), a short "fly report" by email is gold. The things we most want to hear:
Decode results
Which sonde types you decoded — and which you saw on the spectrum but couldn't lock. Serial, frequency, and rough distance to the sonde all help.
Signal conditions
Reported SNR, the antenna you used, gain preset, and anything odd — dropouts, drift, interference from local noise sources.
USB quirks
OTG cable and hub combinations, permission prompts, unplug/re-plug behavior, and any "dead spectrum" moments — with your exact phone model.
Battery & thermals
How long a chase your phone survives with the Airspy attached, whether a powered hub was needed, and any thermal throttling you noticed.
Telemetry upload is opt-in and needs a real callsign; the app only uploads CRC-valid frames. Uploaded data joins the public SondeHub stream, so mark recoveries accurately and keep chase-car sharing (a separate toggle, off by default) deliberate. And the usual chaser rule applies: never trespass to recover a sonde.
How to join
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Email [email protected]
Include your device model, Android version, which SDR you own (Airspy Mini or R2), and your country/region plus a rough distance to your nearest launch site — it helps us match testers to active sites.
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Receive an APK and changelog
When a slot opens we reply with a signed beta APK and release notes. Sideload it — Android will ask you to allow installs from your mail or files app.
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Update as new builds ship
For now, updates arrive as fresh APKs by email: install over the previous build, settings carry over. No store, no auto-update — the changelog tells you what to re-test.
Privacy in the beta
Crash logs are shared only if you choose to send them — nothing is collected automatically. There are no analytics in the app; it phones home to nobody. Network traffic is limited to map tiles and the SondeHub API: fetching public sonde data is passive, telemetry upload is opt-in, and your own position is only ever sent if you enable the separate chase-car toggle (off by default). Details in SondeHub & privacy.
SondeFox isn't on Google Play, and there's no public download. A public release will follow once RS41 field validation completes — that's exactly the work this beta exists to finish.
Meanwhile, kick the tires
The live demo runs the whole UI in your browser with dummy telemetry — no invite needed.