I used operate a CB with a bit more power than the fcc would like to see a CB signal having so I am quite familiar with RF bleed problems. First step is running a ground wire from the frame of your tower to the ground for your house (pretty simple) If that doesn't work it gets a little more complicated. The rf signal can be coming in through most anything you have directly connected to your computer. Internet setups that use coaxial cable are notorious for collecting shortwave RF. This can be alleviated by getting those little screw on caps they sell at radio shack to isolate open outlets, in addition make sure that any cable splitters are grounded. If all else fails try contacting the FCC if they are bleeding over that much dirty signal they are most likely running a high wattage amplifier which is illegal on CB radio bands because of the problem you are having. I hate to advise ratting them out but since I can run pirate wattage any more why should they get to 