Talking on his CB radio on my AM/FM radio. Isnt that wierd?

 

Harmonics issue. It's complicated, but a tweaked CB will cause this. Guy's running something he really shouldn't, according to FCC rules, but they do it. Over wattage amps, 'missing' limiters...

Not a terrible lot you can do about it except report any and all identifying informaton to the cops and/or the FCC, and perhaps they'll catch the guy.

You can have an over wattage amp just play on a bare speaker with just a little bit of wire on it if the conditions are right. Just key on, talk, and the speaker will repeat it. You probably would need a tweaked 1000 watt system or something though... gotta have power to do it. Which is why I say the guy's probably not doing something 'normal' with his setup.