The reception of atmospherics at high frequencies

Abstract

Observation of the amplitudes of atmospherics received in the high frequency band offers a possible method of assessing the distances of their sources. In a preliminary investigation of the potentialities of the technique, atmospherics have been recorded simultaneously at two frequencies in the upper part of the h.f. band. Reception would be expected at both frequencies from sources within ground-wave range (about 100 km). At rather greater distances, such that the receiving point is in the skip zone for both frequencies, no reception should be possible. There should then be a zone from which there should be reception on the lower frequency only, and at greater distances energy should again be received at both frequencies. The preliminary results conform generally with this pattern, and the boundaries of the various zones are in agreement with the ionospheric data derived from vertical incidence soundings. The sources of the atmospherics observed were located by use of the network of direction finders operated by the Meteorological Office. It is concluded that the technique forms a basis for routine estimation of the distances of storms and merits further examination to determine more precisely the accuracy which can be achieved and to overcome certain practical difficulties in the observations.