I'm quite proud of myself. I've managed to fix something. In the kitchen we have an internet radio which works quite well. We need one because there are no other radio signals that work properly there. But sometimes it stops working, It's taken me a while to figure out the cause of the problem, but finally I have the answer.
It's the microwave.
The confusing thing is that because the radio uses a lot of buffering it doesn't stop as soon as the microwave comes on and blocks out the signal. The radio plays for a minute or so and then drops out. Then, when you turn the microwave off it takes a few seconds for the radio to re-establish connections with the server and start working again.
I've checked on-line and apparently this is not an uncommon problem and the microwave radiation isn't hazardous as such, but it is irritating.
For me the fix was quite easy. I just switched the WiFi channel from 6 to 10 and the problem has gone away. Go me.