Accession Number : AD0904715

Title :   An Investigation of Directional Propagation Effects in High-Frequency Radio Source Location.

Descriptive Note : Technical rept. no. 32,

Corporate Author : ILLINOIS UNIV AT URBANA RADIO RESEARCH LAB

Personal Author(s) : Beckwith, Roy Ian ; Bailey, Albert D. ; Rao, N. Narayana

Report Date : SEP 1972

Pagination or Media Count : 246

Abstract : The prediction of horizontal ray-path deviation effects in high-frequency ionospheric propagation arising from large-scale temporal and geographical variations in the ionospheric structure is investigated. A technique for the rapid calculation of these predicted path deviation effects involving the use of the Institute for Telecommunications Sciences ionospheric prediction model is presented. Examples are presented illustrating the use of this technique in high-frequency radio source location applications and the influences of effective ionospheric tilts on a typical mid-latitude path. The representation of the effective ionospheric tilt in terms of a magnitude-azimuth pair is shown to be particularly convenient. Predicted high-frequency propagation path characteristics are compared with experimental data collected during 1967 and 1968 over a 1330 km path between Houston, Texas and Urbana, Illinois. It is shown that the occurence of serious wave-interference effects is strongly correlated with the occurrence of predicted multiple-mode propagation on this path and that predicted instances of propagation failure and propagation support are in agreement with experimental observations. The use of predicted total path loss information for purpose of dominant mode identification is found to provide results consistent with the experimental observations at all times. Predicted diurnal variations in the dominant-mode azimuthal angle of arrival are found to be reasonably consistent with the long-term median variations observed experimentally. (Author)

Descriptors :   *RADIO TRANSMISSION), (*DIRECTION FINDING, POSITION FINDING, HIGH FREQUENCY, IONOSPHERIC PROPAGATION, SOURCES, TIME, AZIMUTH, ANGLE OF ARRIVAL, PREDICTIONS, TEXAS, ILLINOIS, ERRORS, EQUATIONS, RADIO EQUIPMENT, DIURNAL VARIATIONS, INTERFERENCE, IONOSPHERIC DISTURBANCES, BACKSCATTERING, RADIO WAVES, MATHEMATICAL MODELS, ELECTRON DENSITY, MATRICES(MATHEMATICS).

Subject Categories : Direction Finding
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE