Receiving RadioSondes or not in my case

I was inspired by this recent Hackaday (https://hackaday.com/2018/01/05/fallen-radiosonde-reborn-as-active-l-band-antenna/) post to try my hand at receiving RadioSonde messages. A RadioSonde is the box of electronics (Temperature, Pressure monitors etc , GPS receiver, Processor and UHF transmitter) that sits below a weather balloon. Apparently they don’t go and collect them either so they are up for grabs and experimentation.

At the minute though I am failing to decode the messages sent by the UKs Vaisala RS41 RadioSondes. I am using a piece of software called SondeMonitor and the RTL USB dongle with SDRSharp. Last night I received 4 perfect (I think) signals, one shown below not being decoded 🙁

Further testing will commence shortly as they lift of at 11:15 and become audible at 11:30ish. Wish me luck.

Paul
M0ZMB