Accession Number : AD0657949

Title :   MEASUREMENT AND PREDICTION OF GROUP VELOCITY AT VERY LOW RADIO FREQUENCIES.

Descriptive Note : Technical rept.,

Corporate Author : HARVARD UNIV CAMBRIDGE MASS DIV OF ENGINEERING AND APPLIED PHYSICS

Personal Author(s) : Pierce,J. A.

Report Date : JUL 1967

Pagination or Media Count : 123

Abstract : Sample measurements of times of arrival of Omega signals in the VLF frequency band are reduced to approximate times of propagation and then to the reciprocal of the relative velocity of propagation. A function of the altitude of the sun is then found which, when integrated along the transmission path, yields a synthesis of the transmission time. Two of these functions for two frequencies yield the group transmission time for a difference frequency. It is suggested that this function will make a convenient means for intercomparing data for different paths and different frequencies, in the expectation that corrections can then be made for various factors that have a minor effect upon the speed of propagation. Identification of the importance of these factors should lead to better prediction of the absolute velocity for any path at any time. (Author)

Descriptors :   (*RADIO TRANSMISSION, VERY LOW FREQUENCY), VELOCITY, PROPAGATION, RADIO NAVIGATION, PHASE, TIME

Subject Categories : Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE