Re‐use of Recovered Radiosondes - projecthorus/sondehub-infra GitHub Wiki
In general, SondeHub does not support the re-flight of unmodified meteorological radiosondes.
Instead, we recommend that they be re-flashed with open-source replacement firmware, e.g. RS41ng so they can transmit in either ISM or amateur radio bands, using open source modulations e.g. Horus Binary.
However, there are some limited cases where re-flights of recovered radiosondes using stock firmware may be applicable, e.g. by research institutions or other cases where accurate meteorological data is required. For these cases, we can provide some advice on how best to modify these radiosondes to avoid data problems in the SondeHub database.
Licensing
In most countries, transmissions within the 400-406 MHz radiosonde band requires an appropriate license. It is your responsibility to ensure you understand the licensing requirements for your country and abide by them!
We're still gathering information on what types of license are available in different countries, the ones we do know of are:
- United States - Federal Communications Commission (FCC) "Experimental Radio Station Construction Permit and License"
- The station must be listed as 'Mobile', with a suitable radius from the launch point to cover all planned flight paths.
- Australia - A suitable apparatus license from the Australian Communications and Media Authority (ACMA)
If you know of the licensing approach in your country, please contact us at [email protected] !
Frequency Coordination
Along with a valid license (which may or may not define a specific operating frequency), you need to carefully consider frequency coordination, to avoid interfering with other radiosonde launch sites and other spectrum users near your location. This may occur as part of your licensing process, but we recommend running your own radiosonde receiver and watching SondeHub during launch times to build up a census of what frequencies are in use in your area.
Re-flying a radiosonde on the same frequency as it originally flew on is a very bad idea (even if you have obtained a license), and could lead to interference with the primary user of that frequency!
Serial Numbers
Where possible, we do not recommend re-flying a radiosonde with the same serial number that was used during its initial flight. This can cause confusion with the sonde launch site allocation system used in SondeHub.
Instead we recommend that the serial number be modified to something that is outside of the typical serial number ranges for the particular radiosonde type in use. Unfortunately, it appears that only Vaisala RS41 sondes can be modified in this way, so we can only provide advice for these.
Vaisala RS41
The standard Vaisala RS41 serial number format is of the form YWWDxxxx, where:
- Y is a year code, where S = 2020, Z = 2027, wrapping back to A for 2028.
- WW is the week number (1-52) of manufacture,
- D is the day-of-week of manufacture
- xxxx is a sequential number for that day.
It is possible to modify the serial number via a UART connection to the radiosonde, and a 'service menu', information on which you can find here. This also provides information on how to adjust the transmit frequency (between 400-406 MHz).
Our recommendations for changing the serial number are:
- Leave the year code as-is.
- Replace the week-number and day codes with a number in the range 530-999, ensuring the week number portion is outside the normal range, and hence the overall serial number will not collide with any other stock radiosondes. We may consider assigning numbers to groups that are intending on re-launching radiosondes like this. Please contact us if you are interested in this approach!
- Either leave the sequential number as-is, or use a value that increments for each radiosonde that you re-use.
Launch Sites
If you are intending on performing many radiosonde launches from a particular launch site, we can add your site into our database so that flights are assigned to that site, allowing easier access to telemetry.