Accession Number : ADA017375
Title : Studies on the Phase Spectra of VLF Sferics.
Descriptive Note : Technical rept.,
Corporate Author : TEXAS UNIV AT AUSTIN APPLIED RESEARCH LABS
Personal Author(s) : Trochta,Robert T. ; Horton,Claude W. , Sr
Report Date : 25 AUG 1975
Pagination or Media Count : 61
Abstract : The phase characteristics of long range sferic signals are studied in detail over the frequency range of 9 to 20 kHz. When the experimentally measured phase of a sferic is fitted with a straight line by the method of least squares, the deviation of the phase from this straight line shows a pattern that is characteristic of the nature of the propagation path. The phase deviation for daytime paths of length greater than 4000 km behaves as predicted by the theoretical behavior of the first propagation mode: daytime paths of ranges between 1500 and 3500 km can be explained by two modes. The agreement between experimental and theoretical values suggests that the phase of the sources of these atmospherics is a linear function of frequency. Although absolute values of group velocity cannot be determined, the variation of group velocity with frequency agrees with the theoretical predictions based on one and two modes of the earth-ionosphere cavity.
Descriptors : *Atmospherics, Very low frequency, Electromagnetic wave propagation, Radio transmission, Modes, Phase, Spectra
Subject Categories : Radiofrequency Wave Propagation
Distribution Statement : APPROVED FOR PUBLIC RELEASE