1) Are the lighting fixtures solidly grounded?
2) Are the lighting fixtures suspended or mounted to structural metal?
3) Are the correct bulbs installed(T8 vs. T12)?
4) Are the radios on the same circuit as the lamp fixtures?
5) Are they listening to AM or FM?
6) Is the signal they are trying to receive strong or weak?
Questions 1,2,& 5 relate to radiated interference.
Question 3 is because I do not know what happens with mismatched bulbs and ballast.
Question 4 relates to conducted interference.
Question 6 is about the relative strength of the interference to the desire signal.
