Radio or TV interference occurs when a high-frequency signal distorts the incoming signal to the cable or antenna input of televisions and radios. Cordless telephones can also be affected. The causes of these problems can be easy to identify. When a common appliance generates electrical noise that interferes with the TV or radio, it may be easy to match the cause with the problem by watching to see what is coming on when the interference occurs.
Unfortunately, many of the causes of interference cannot be seen or heard. Electromagnetic interference sources may originate inside the home or can result from certain environmental conditions. Finally, interference can be caused by activities in a neighbor's home or elsewhere in the electric utility's system.