Equipment is described for studying atmospheric radio noise by means of continuous-film photography and by measuring the amplitude probability distributions by a pulse-counting technique. Results are given for observations in England during the summer and autumn of 1956. The observations were made in a bandwidth of 400 c/s.No simple mathematical representation of the amplitude probability distribution has been found which will fit all conditions, and a graphical presentation is suggested as a means of providing communication engineers with the required data.The high-frequency radiation consists of a burst of quasi-continuous noise throughout the duration of the flash. This suggests that a burst-duration distribution may be a useful additional measurement in defining the interference effect of the noise.