Accession Number : AD0820109

Title :   HF AND LF PROPAGATION MODELS FOR INTERFERENCE PREDICTION.

Descriptive Note : Final rept. Mar 66-Jun 67,

Corporate Author : BELL AEROSYSTEMS CO TUCSON AZ ARIZONA OPERATIONS

Personal Author(s) : Spogen, Leo R., Jr. ; Lloyd, John L. ; Moore, Elliot P.

Report Date : AUG 1967

Pagination or Media Count : 236

Abstract : This report describes accomplishments in devising propagation models for the HF, LF, and VLF frequency ranges. An HF computer model using parabolic layer theory is described. Analysis parameters for a parabolic layer over a spherical earth are obtained from (1) predicted F2-layer ionospheric characteristics, (2) available E-layer characteristics, and (3) a recently developed quasi-empirical determination of layer semithickness. Ray-tracing equations are used to obtain an output directly applicable to interference analysis. Techniques employed in this model, unlike most models, identify possible stable and unstable modes. In addition, the propagation prediction analysis is performed before antenna characteristics are considered in the overall technique. These factors and statistical considerations give a usable HF skywave propagation model for interference analysis. The LF and VLF frequency ranges require considerably different types of analyses, because only the very lowest extremity of the ionosphere is used. A model has been devised and is described which uses an ionospheric reflection coefficient program and a wave hop integral program. Proper use of these two factors allows an estimate of the propagation loss that occurs over an LF or VLF circuit.

Descriptors :   *MATHEMATICAL PREDICTION), *PROPAGATION), (*RADIOFREQUENCY INTERFERENCE, (*COMPUTER PROGRAMS, RADIOFREQUENCY INTERFERENCE), (*MATHEMATICAL MODELS, INFORMATION THEORY, IONOSPHERIC PROPAGATION, EQUATIONS, HIGH FREQUENCY, LOW FREQUENCY, VERY LOW FREQUENCY, ATTENUATION, INTEGRAL EQUATIONS.

Subject Categories : Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE