Tremendous RF problem -- phono stage is a radio

Thank you all for your suggestions -- the "military" one is excellent. It turns out that I have some mu metal (the contents of one's garage are sometimes rather curious), and I can have it cut to fit the walls of a box that will cover the phono stage, not exactly beautiful, but the phono section is hiding in a cabinet anyway, so it won't matter. I suppose I could allso use an old wire cage that once housed a pet rabbit -- another long story. One wonders whether Faraday would be amused.

Changing the loading of the cartridge made a colossal difference. At 500 ohms it essentially went away. Also, I cut up my sheet of mu metal and placed it around the phono preamp (bye bye aesthetics), and that helped too. So the problem is more or less "solved." Thank you all for your suggestions. It turns out that the radio station I was receiving so well recently went from 1 KW to 10 KW (it is less than a mile away), and that certainly did not help matters either. In fact that probably was the major culprit.