Auroral noise at HF

Auroral noise has been the subject of extensive private discussion. Very little has been published, however, because it has proved exceedingly difficult to identify positively the observed (effects as pure noise and not as anomalously propagated signals distorted beyond intelligibility by the aurora. The initial reference to possible auroral noise appears to have been made by Covington [1947] in reporting 3000 Mc/s observations during periods of strong magnetic activity. Additional reports of microwave noise were made a few years later [Forsyth, Petrie, and Currie, 1949; Covington, 1950; Chapman and Currie, 1953], although the possible connection between microwave noise and the high-frequency noise described here is not obvious.