LXXXVII. A study of individual radio atmospherics received simultaneously at two places

Summary A previous paper (Bowe 1951) described a method of studying the propagation of radio waves of frequency 2 kc/s to 10 kc/s over the surface of the earth, by observing the responses of narrow-band receivers to individual radio atmospherics. The present paper describes an extension of these observations in which the same method was used simultaneously at two places, Cambridge and Aberdeen, 550 km apart. The narrow band receivers at both places were tuned to frequencies 7·5, 5·0, 3·5 and 0·6 kc/s. By comparing the responses at the two places, the attenuation factors for each frequency could be found. The sources of the atmospherics were located by the ‘Sferic’ direction finding system of the Meteorological Office, supplemented by a direction finder at Cambridge. Most of the observations were made at about noon. The results are presented as tables giving the propagation factor for 1000 km path, for the four frequencies studied. It was found that waves of frequency 0·6 ke/s are less attenuated than waves of frequency 3·5 kc/s. The results for 7·5 and 5·0 kc/s appear to indicate that the attenuation is less in winter than in summer.