Rather obvious EMC problem...

I noticed just now that the Raspberry Pi that runs my ADBS receiver and also has '1-Wire' temperature sensors for the central heating registered a pipe temperature of a theoretically impossible -1700C.

Oh, did I mention that my 20m / 6m dipole is in the loft... and the Pi is in the loft... about 2 feet from one leg of the dipole... Hmmm. I can see a connection here given the timestamp was the same as a JT65 transmission.