EXPERIMENTAL RESEARCH INVESTIGATION OF EXTREMELY LOW FREQUENCY PROPAGATION.
SPACE-GENERAL CORP EL MONTE CALIF
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ELF electromagnetic wave propagation was investigated by measuring the characteristics of cw signals transmitted over a 400 cps link established between Bishop, California and Rome, New York a distance of approximately 4000 km. Data which could be reduced to yield signal strength, attenuation rate, transmission path phase variations, and atmospheric noise amplitude probability distributions APD was recorded at the Rome, New York receiver site. Data from the current and previous contract has been compiled to show the range of measured propagation constants. The median measured attenuation constant rate is 3 db1000 km for a nighttime path and 7.8 db1000 km for a daytime path. The median measured diurnal phase shift constant, through the sunrise period, is 0.13. Measurements are compared with path characteristics calculated using existing theoretical treatments of ELF propagation. Samples of atmospheric noise impulse data and the corresponding atmospheric noise amplitude probability distribution are presented. Author