ABSTRACT
Moment method modeling has several big advantages over the traditional ways of directional antenna analysis. Moment method modeling is based on the premise that an antenna is characterized by a collection of arbitrary thin, straight wires in free space or over a ground plane. In the amplitude modulated (AM) broadcast antenna world, all our work is over a ground plane. Modeling predicts tower currents and voltages that are directly related to directional antenna parameters. In moment method modeling of an antenna, the radiator is divided up into segments. The Federal Communications Commission (FCC) rules permit moment method modeling as a means of performance verification of AM directional arrays in certain cases. The FCC rules for modeling of AM broadcast antennas have some further limitations on segmentation and radius. The FCC's AM modeling rules require that "reference field strength measurement locations shall be established in directions of pattern minima and maxima".
