I have had two over the range Microwave ovens, a Quasar and recently a GE Profile. When running either they create noise on the AM of my old 1972 Panasonic tabletop radio on the top of the fridge.
The current crop of dept store AM/FM radios are known to have crummy AM reception. It is just built in so they can say it is an AM/FM model. The designs are not very good at rejecting noise.
My easy solution is to turn off the radio when the microwave is on.
If you have to listen to it with the microwave on you can try the following..
------------------
Low Noise Antenna Connection From: snipped-for-privacy@space.mit.edu (John Doty) Newsgroups: rec.radio.shortwave Subject: Low Noise Antenna Connection Date: 26 Nov 1993 16:55:24 GMT
----------------------------------------------------------------------------