In this paper, we will limit our discussion to the electrical noise caused by power lines, The most common signature of power-related electrical noise is the fact that it moves slowly through the television picture in bands. Two bands being characteristic of single phase power and six bands indicating three phase. It is at this point that most system technicians make their first mistake -~ they jump to the conclusion that the cause is ''the substation northeast of town", "the factory 15 miles south of town" or some other well-known power landmark. The technician makes his second mistake when he drives to this location, hears noise on his car radio and concludes that this must be the source. These two common errors result in wasted time for the utility company engineers as they try to eliminate all noise at that facility and frustration for the technician when his efforts do not remove his interference problem.