The current variations in a short-wave square frame aerial revolving in its own plane
L.S. Palmer, Roy Witty · Proceedings of the Physical Society · 1935
From a theory of the action of short-wave frame aerials outlined in previous communications it was concluded that the current at any point in a rectangular frame aerial should vary with time as the frame revolved in its own plane. If the current-measuring instrument moves round with the frame, complications arise because the instrument records not only the current-variations due to changes in what was called the degree of formatization of the frame, but also those due to the fact that the instrument passes in succession through the current nodes and antinodes which have been shown to be fixed in space and not to revolve with the frame. Hence current-measurements have been made, firstly with the frame fixed and the instrument moving round the frame, and secondly with the instrument fixed in space as the frame revolved. The apparatus and methods employed are briefly described. The current-variations observed in the two sets of experiments conform approximately to those predicted from the theory. The results lead in general to the conclusion that when a square frame aerial is used with short waves and revolves in its own plane then, in addition to spatial current-variations round the perimeter of the frame due to the formation of fixed current nodes and antinodes, there may also be temporal current variations at any fixed point due to the fact that the frame may become alternately formatized and deformatized as it revolves.