In the past, I've talked about the RS92-SGP radiosonde launched from Madrid-Barajas. Recently, Barajas has replaced the RS92-SGP with the newer Vaisala RS41-SGP (except for ozone sounding, which is is still done with the RS92). The new radiosondes transmit at 401MHz and are released daily at 11:15 and 23:15 UTC.
In that post, I described about how to receive the position data from the RS92 and plot it in Viking in real time. Since then, a few features such as FEC decoding have been added to the RS decoder software, so I have decided to give this a go again with the newer RS41. This will be a complete walk through, since some people are interested in setting up unattended decoders, perhaps running on a Raspberry Pi.