Accession Number : AD0629226

Title :   EFFECTS OF TOPOGRAPHY AND REFRACTIVE INDEX ON LOW-ANGLE 3 CM RADIO WAVES.

Descriptive Note : Technical rept.,

Corporate Author : DEFENSE RESEARCH LAB UNIV OF TEXAS AUSTIN

Personal Author(s) : Tomlinson,Hugh T.

Report Date : AUG 1958

Pagination or Media Count : 117

Abstract : This report describes a series of radio propagation tests and the analysis of the data obtained. The purpose of the tests was to study the effects of meteorological and terrain conditions on horizontally-radiated 3 CM radio waves. Terrain effects were measured by recording field intensity patterns as a function of height, using the elevator of a 275 foot tower to carry the receiver. Several transmission paths were used to determine the effect of different types of terrain. The magnitude of the field intensity changes indicated effective coefficients of reflection of 0.1 to 0.4 for both horizontal and vertical polarizations. One transmission path provided an excellent example of knife-edge diffraction. Diurnal movements of height-gain patterns were effectively related to changes in the index of refraction of the transmission atmosphere. By using the differential change in average index of refraction for the direct and reflection paths, an agreement between calculated and measured direction of null movement was obtained in 29 out of 34 cases. (Author)

Descriptors :   (*RADIO WAVES, PROPAGATION), TERRAIN, METEOROLOGICAL PHENOMENA, ATMOSPHERIC REFRACTION, REFRACTIVE INDEX, MICROWAVES, X BAND, RADIOFREQUENCY

Subject Categories : Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE