Musical Thunder

Radio Record, Volume IV, Issue 17, 7 November 1930, Page 9

Musical Thunder

USICAL thunder, accompanied by a vivid electrical display, was encountered by radio engineers recent-: ly in experiments with high-powered short-wave broadcasting. The thunder, created artificially, was converted into music corresponding to the input at the radio microphone. In handling powers above fifteen kilowatts on the. short waves, the engineers found that vivid coronas flashed when attempts were made to modulate. Since the power supplying the arc. was modulated with music, the are alternately collapsed and built up according to the modulation, this action setting up air-wave vibrations similar to thunder. Instead of the roar and roll of real thunder, however, it was a musical sound similar to the music being broadcast, and persons 400 feet away thought they were hearing the output of a giant. loudspeaker. The are finally melted the copper and caused the antenna to drop. The trouble was solved when larger antenna wire .was used, and a large corona plate ‘was placed at each end; making it possible to obtain thirtyfive kilowatts, perfectly modulated in the antenna, without coronas.