The addition of a field strength contour capability to NEC-2 and its application to the field emitted by an AM radio broadcast array

Abstract

This paper presents the development and the use of a FORTRAN program that was added to a NEC-81 version of the well known NEC-2 program for the purpose of computing field strength contours. Whereas a field radiation pattern identifies the field variation for a constant observation distance about the antenna, a field strength contour identifies the distance variation for a constant field strength (|Ez| here). Because field strength contours are meaningful in the near-field as well as the far-field zones, they are useful in providing a picture of the emission process everywhere about the antenna.