Distribution of Peaks in Atmospheric Radio Noise

Probability distributions of peaks on atmospheric radio noise were investigated by recording noise bursts over their complete dynamic range of about 75 dB. The investigations were made at a large number of frequencies, with a large number of bandwidths and above different datum levels to enhance the utility of the results. Probability distributions of peaks were found to follow a single log-normal distribution or a combination of two or more log-normals irrespective of the frequency, bandwidth, and the datum level. The standard deviation of distributions was found to range from 2 to 22 dB. Reasons for such a wide range of standard deviations are given.The composite distributions degenerate into a single log-normal distribution when the datum level is raised sufficiently indicating that the higher and lower amplitude peaks arise from separate sources. The results have been compared with the similar published work corresponding to different latitudes, frequency ranges, and bandwidths and possible reasons for the observed differences are offered.