I have six of eight foot T8s, 24 bulbs total. They don't interfere with my FM radio. I also have a four foot workbench light, which wasn't a problem until I had to replace its ballast. Now it interferes with the radio, so my conclusion is that not all ballasts are the same.
I should note that the workbench light is on the same circuit as the radio, while the main lights are on the opposite leg. You might try switching your circuits around so the lights and radios aren't on the same leg.