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THE INFLUENCE OF FINITE GROUND CONDUCTIVITY ON THE DIRECTIVITY PATTERNS OF VERTICAL ANTENNAS,
FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO
Pagination or Media Count:
The author shows that the amplitude of a radio wave propagating at a finite angle to the surface of the earth, taking into account the earths conductivity and the directivity of the antenna, can be calculated in terms of the components of the Hertz vector and of the electromagnetic field of a vertical antenna over an ideal earth, by introducing the concept of surface impedance and the attenuation factor. He then presents directivity patterns for a dipole placed on the surface, as functions of the parameters of the earth that are encountered in practice. An analysis of the numerical data shows that the influence of the earths finite conductivity can cause an appreciable attenuation of a wave reflected from the ionosphere, especially in the case of poorly conducting ground.
APPROVED FOR PUBLIC RELEASE