So an update on the earlier radon gadget. I received the BLE sniffer widget, but, wow, its a bit complex to use. Keeping an eye on the basement Radon, and you can see, it fluctuates quite a bit. We are well under the 'safety' limit (which there is some discussion on, some being of the opinion there is no safe limit, others that if its similar to the outdoor levels you can't do much better).
In Europe, the consensus seems to be 100Bq/m^3 is the threshold to start mediation. Here in Canada the consensus is 200Bq/m^3. My peak is 53Bq/m^3, with an average around 30. So good so far. But its deep-winter here, once spring starts and ground-water flows, maybe I'll have an issue.
So, worried about your basement? A little more bluetooth gadgetry and you can know for sure. And yes, that test you did once years ago is meaningless, you need to test all the time, see my results.