LoRa on Vaisala RS-41

[IZ5WWB]

Hello everybody,

just a beginner's question: I have two Vaisala RS-41 sondes that I'd like to reprogram for LoRa transmission of GPS data, telemetry, etc.. for HAB applications.

I suppose that some firmware already exist addressing this goal. Could someone from the forum kindly give me some references? Thanks.

73, Daniele IZ5WWB

[Richard Ibbotson]

As far as I know the SiLabs radio chip in the RS-41 does not support the LoRa modulation scheme. You need to look to a different modulation scheme like GFSK.

Or a  LoRa compatible radio.

Richard M0SKP

Sent via Richard's Phone

On 22 Apr 2026, at 19:29, IZ5WWB <radioq...@gmail.com> wrote:

Hello everybody,

just a beginner's question: I have two Vaisala RS-41 sondes that I'd like to reprogram for LoRa transmission of GPS data, telemetry, etc.. for HAB applications.

I suppose that some firmware already exist addressing this goal. Could someone from the forum kindly give me some references? Thanks.

73, Daniele IZ5WWB

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[Radiocose]

Yes Richard, thanks. In the meantime I read something around on this subject and I believe Horus will be the best option.

To view this discussion visit https://groups.google.com/d/msgid/ukhas/A06CAD08-91D3-4361-A6B4-533102E249C6%40gmail.com.

[Ross G6GVI]

From: https://github.com/mikaelnousiainen/RS41ng

The radiosondes can be reprogrammed to transmit different kinds of RF modulations (morse code, APRS and different FSK modulations) on the 70 cm (~433 MHz) amateur radio band. The radiosonde contain Ublox GPS chips, so it can be used as a tracker device, e.g. for high-altitude balloons.

The RS41ng firmware is just one example of what can be achieved with the hardware of these radiosondes!