A set of procedures to be followed to cope with reradiation of AM broadcast signals from power lines and other large metallic structures is provided. Reradiation may be described as electromagnetic waves radiated from a structure that has parasitically picked up a signal from the environment. A simplified prediction technique called a survey is described to determine which structures could possibly cause a problem. Guidelines for measurements and data analysis are included.

This guide provides a set of procedures that can be used to cope with reradiation of AM broadcast signals from power lines. It can also be applied to other large metallic structures. While the procedures listed in this guide may be applicable to reradiation problems from other medium frequency (MF) sources, such as navigation beacons, they are not intended to be applied to reradiation problems from higher frequency sources, such as television broadcast signals. This guide is not designed to be applied as legal evidence of harmful effects of a reradiating structure upon an AM broadcasting station. In some jurisdictions, the government regulatory or licensing ...

An AM broadcast array is carefully constructed to radiate strongly towards listeners and weakly in directions where interference to other stations could result. Reradiation can occur when the broadcasted signals are parasitically picked up by a large metallic structure and then rebroadcasted, or reradiated, from that structure. Many structures may reradiate an AM and other radio signals, e.g., power lines, communications towers, water towers, and buildings. This can result in a decrease in signal towards listening areas and an increase in signal in protected directions. The process of predicting, measuring, analyzing, and mitigating the interference is compl...