Angle of Arrival Measurements of 3.2-Centimeter Radio Waves

Author: Enenstein, Norman Harry

Year: 1949

Degree: Dissertation (Ph.D.)

Advisor: Pickering, William Hayward

Committee Member: Unknown, Unknown

Option: Electrical Engineering; Physics

DOI: 10.7907/sm1m-5x15

Abstract

A study was made of the atmospheric and terrestrial phenomena that influence the angle of arrival of microwaves at a receiving station. The primary atmospheric phenomenon studied was the refractive bending due to vertical gradients of the index of refraction. Terrestrial effects of multi-path radio ray transmission were considered.

A theoretical study of the contribution of free water in the atmosphere in the form of water droplets to the atmospheric index of refraction was made. It was found that water droplets do not add appreciably to the refractive index. Also a method of theoretically determining directly the angle of arrival due to refractive bending was derived.

Angle of arrival measurements were made at the California Institute of Technology, Pasadena, California, over a 7.15- mile path from Mt. Wilson, California, to Cal Tech. Measurements were made using 3.2-centimeter radio equipment with a metal lens antenna. Variations in angle of 0.31 degree were measured. These variations were greater than to be expected by refractive bending. Multi-path propagation is believed to have caused these comparatively large variations.

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