Sun-Spot Cycle

Radio Record, Volume I, Issue 51, 6 July 1928, Page 2

Sun-Spot Cycle

EFFECTS ON RADIO ae SCIENTIFIC OBSERVATIONS Wits the eleyen-year sun-spots eyele reaching its maximum this American summer, operators at long wave radio stations (says a United States Associated Press message) are looking. forward to the best hot weather communication in years. Observations by scientists show that long wave daylight signals are stronger during periods of great solar activity. Dr, L, W, Austin, of the United States Government Bureau of Standards, an authority on radio wave propagation, says that studies made by him revealed that the signals, both from distant stations and those only 200 miles away, were much stronger in 1927, when the sun-spot eyele was near its maximum, than in 1923, when it was at its minimun. These signals should be even stronger this year, when solar activity reaches its peak. Old Sol, however, is the nemesis of night-time reception on the broadcast hands. Observations by G. W. Pickard, vadio expert of Boston, have shown that night signals in the broadcast range grow weaker when the nuniber of sun spots inereases, Dr. Austin says. "This reversal of the effect of solar activity corresponds with the conclusions of the engineers of the Bell Telephone Inboratories that magnetic storms, which are known to be connected with sunspots, weaken medium and long wave signals at night and stvengrhen them in the daytime," Dr. Austin adds, "The evidence regarding the influence of magnetic storms and solar activity on ultra short waves is somewhat, conflicting. There are many authentic reports of pdor reception at the time of intense magnetic storms while at the same time the long continued observations of Dr. A, H. Taylor, of the United States Naval Research Laboratory, as averaged by Mr. Pickard, indicate an increase of night signals with inereusing sun spots or the reverse of the effect on longer wares."