Accession Number : AD0479374

Title :   HF COMMUNICATION EFFECTS: FREQUENCY DISPERSION AND DOPPLER SHIFT.

Descriptive Note : Final rept.,

Corporate Author : STANFORD RESEARCH INST MENLO PARK CA

Personal Author(s) : Shepherd, R. A.

Report Date : AUG 1965

Pagination or Media Count : 87

Abstract : This effort was part of a program of research to determine the effects of high-altitude nuclear explosions on HF radio communications, using naturally occurring disturbances to simulate nuclear distrubances. Phase-stable transmissions at 7.366 Mc over a transauroral path from Thule, Greenland and over a mid-latitude path from Fort Monmouth, New Jersey were received at the SRI field site near Palo Alto, California. Both of these paths were paralleled by step-frequency oblique-incidence ionospheric sounders. Power spectra of the received CW signals were computed, enabling the identification of individual ionospheric modes by their separation in Doppler shift. Examples of power spectra of simple and of more complex mode structures, including off-path modes, are given. Statistics of the frequency dispersion and the Doppler shifts of the Thule and Fort Monmouth signals are compiled for selected data in February, March, and June, 1964. Comparisons show that while Doppler shifts for the two paths are similar in magnitude, the frequency dispersion of signals on the transauroral path is about ten times as great as that on the mid-latitude path. (Author)

Descriptors :   *IONOSPHERIC PROPAGATION), (*RADIO SIGNALS, (*RADIO TRANSMISSION, IONOSPHERIC PROPAGATION), (*COMMUNICATION AND RADIO SYSTEMS, IONOSPHERIC PROPAGATION), FREQUENCY SHIFT, IONOSPHERIC DISTURBANCES, SIMULATION, NUCLEAR EXPLOSIONS, HIGH ALTITUDE, RADIOFREQUENCY POWER, RADIO RECEPTION, DOPPLER EFFECT, STATISTICAL DATA, ATTENUATION.

Subject Categories : Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE