ABSTRACT
This chapter demonstrates the assets and liabilities of Numerical Electromagnetics Code (NEC)-2 in practical applications to amplitude modulation broadcast directional arrays. In addition to comparing some calculated and measured data, the chapter provides a few general opinions and suggestions that are useful to increase the utility of NEC-2 for broadcast work. NEC-2 runs were made to determine the passive self-impedance of each tower both with the companion towers open at the base and with the companion towers shorted at the base. In time, the self-impedance of each tower was measured under conditions similar to those used in the NEC-2 analysis. Notwithstanding the lack of agreement between calculated and measured self-impedance, the calculated and measured array drive point impedances are in relatively good agreement. It is reasonable to recognize that the drive point impedances are controlled more by the mutual coupling between radiators than they are by the modeling details of the individual radiators.
