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Imminent M20 Serial Number Issue #161

Description

@darksidelemm

Sometime in early 2025 newer M20 sondes were seen with a difference in serial number encoding. This resulted in incorrect serial numbers (not matching the sticker) being decoded and uploaded to sondehub.

The typically error is seeing a serial of xxx-2-xxxxxx instead of the correct xxx-1-xxxxxx.

At the time, these newer M20 sondes were fairly rare, so the issue wasn't urgent.

In auto_rx v1.8.1 a change was made to fix M20 serial number decoding. A similar change may have been made in rdz_ttgo_sonde at some point (To be confirmed).

More of these newer M20s are now being seen, and we can expect more to make their way through the supply pipeline over the next year.

Recommendation: Block uploads for M20 sondes for software:

  • radiosonde_auto_rx: <1.8.1
  • SondeMonitor: all (it looks like the latest sondemonitor 6.2.8.9 has the issue
  • rdz_ttgo_sonde: TBD. Unsure if there is a fix in rdz_ttgo_sonde yet.

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