Antennas for Medium‐Frequency Broadcasting

Abstract

Since the 1940s, there has not been significant development in the area of the antenna element itself as selfsupporting and guyed radiating towers continue to be used much as they were at that time. New developments have principally involved auxiliary equipment used to test and monitor the antenna system and the means by which the antenna is theoretically analyzed. Digital antenna monitors are used today to accurately monitor the relative current magnitudes and phase relationships of the towers in a directional array while portable solid‐state field strength meters are used to measure radiation patterns. Advances have also been made with improved RF current meters, sampling transformers, and impedance measuring equipment. The design of medium‐frequency broadcast antennas for optimized performance has also seen tremendous advances with the introduction of numerical solutions to electromagnetic problems and nodal modeling of feeder systems made economically possible with personal computers vastly simplifying both design and implementation.