Some measurements of atmospheric noise levels at low and very low frequencies in Canada

Abstract

Atmospheric noise levels at 11, 35, and 135 kc/s have been recorded at Ottawa and Churchill for a period of 1 year beginning September 1958. A statistical analysis of the noise as a function of frequency, time of day, and season of the year has shown the following: (1) The same noise storms determine the noise levels received at both locations (since the beginning of the midday maxima occurs at the same time, whereas local time differs by 1 hour, and the departures of the daily median from the monthly median varies in a regular way and is the same at both locations). (2) The noise level decreases with increase of frequency more rapidly than predicted by CCIR (especially in winter when the noise storm centers are most distant). (3) The morning decrease in noise level varies in a regular way over the year, as expected from the sunrise time, between the receiver and the location of the most active storm centers. (4) The equipment measures both rms and the average noise levels. Only at the highest frequency during the winter season is a regular daily variation obtained.