Comparative statistics of atmospheric radio noise and man-made radio noise below the HF band

An analysis is presented of atmospheric radio noise data recorded at 60 kHz, 100 kHz and 5 MHz, as well as man-made radio noise at 200 kHz. The atmospheric radio noise typifies that originating from active thunderstorm cells, while the man-made radio noise may be taken as representative of that from electrically powered industrial equipment. The amplitude probability distribution and time probability distribution between positive crossings of the noise envelope are assessed to aid in the design of noise reduction circuitry for HF communications systems.