bazjo: How does Radiosonde Telemetry work?

Discover how radiosondes collect weather data from disposable balloons, including their unique telemetry format, encoding, and decoding, and explore the importance of frequency stability and data collection.

Key takeaways
  • Radiosondes are used to collect data from weather balloons and are disposable because it’s unknown where they will land.
  • They have specific requirements for stations and radiosondes.
  • Radiosondes use FM modulation with a modulation index that is the quotient of high and low frequencies.
  • The transmitter is NRND and uses a grey text indicator.
  • The SANT transmitter uses a heated humidity sensor and non-volatile memory data (NVM) for calibration and configuration.
  • The RS41 model has different variants including non-volatile memory (NVM) and temperature and humidity sensors.
  • The Weizsler RS-41 Radiosonde is used in Germany and has a FSK demodulator.
  • The DFM Radiosonde is used in the US and has a 2FSK demodulator.
  • Radiosondes use Manchester decoding and 2-state phase shift keying.
  • The GRUAN project develops GRUAN data products for each instrument.
  • Radiosondes use X-Data protocol for external data collection.
  • The audio data is decoded and analyzed using Audacity.
  • The telemetry format stays the same since the 90s.
  • The ID is encoded in the first nibble of the sensor field.
  • Non-volatile memory data contains calibration and configuration values.
  • Frequency stability is important for Radiosonde operation.
  • The GM variant has a barometric pressure sensor.
  • The SGP variant has a solar-powered humidistat.
  • The DFM Radiosonde format is used in the US.
  • Frequency shift keying is used for binary data.
  • Radio receivers have problems, but not accounted for in data products.
  • The XOR mask is used for data encoding.
  • Frequency modulation is used for binary data.
  • Manchester symbols are used for data encoding.
  • GRUAN data products are open source.
  • Radio enthusiasts can use the radiosondes to test their equipment.
  • Radiosondes are important for meteorological research.
  • Frequency stability is important for Radiosonde operation.
  • XBEE radio modems are used for data transmission.