ABSTRACT
This chapter provides the station engineer with an understanding of some of the basic concepts of antenna design and an appreciation for the complexities of this specialty. The chief purpose of a broadcast antenna system is to radiate efficiently the power supplied to it by the transmitter. A second purpose of Medium wave broadcast (AM) antenna system is often to concentrate the power in desired directions to cover populated areas and to suppress it in other directions to protect the coverage of other stations sharing the same or closely adjacent channels. The signals radiated from the antenna are propagated through space to each receiving antenna. Most antenna systems that employ tower-mounted sampling loops use isolation coils wound of sampling line across their tower bases. Power lines near AM antennas are more complicated to analyze than simple vertical structures, as their support poles or towers are generally interconnected at their tops by one or more horizontal ground conductors.
