Influence of Sunspots on Long Distance Broadcasting

Manawatu Times, Volume 68, Issue 85, 10 April 1943, Page 7

Influence of Sunspots on Long Distance Broadcasting

LONDON, April 8. An experiment with an important bearing on long-distance radio broadcasting was described by Sir Edward A. Appleton, lecturing at the Instituto of Electrical Engineering. He said tho work began in 1931 when he in cooperation with Mr. R. Naismith devised a radio method of measuring the concentration of electricity in the atmosphere 60 to 160 miles above the ground. They suspected after two years thai. this election concentration was varying in sympathy with tho appearance of sunspots and realised the need for observation of a Complete sunspot cycle of just over eleven years. Observations were now being made in other parts of the world but the British records are the longest available and are expected to show some of the ultraviolet light emitted from the sun increased as much as 120 per cent as sunspot acivity changed from minimum to maximum conditions. But the light thus changed was absorbed in the upper atmosphere and therefore was not detectable from the ground. Sir Edward Appleton concluded that it was now certain that the range of shortwave lengths available for longdistance radio broadcasting increases very substantially with solar activity, therefore it will certainly be necessary ithat the international allocation of ■such wavelengths after the war should take account of variations during n sunspot cycle indicated by these new results.