Italian inventor and engineer Guglielmo Marconi (1874-1937) developed, demonstrated and marketed the first successful long-distance wireless telegraph and in 1901 broadcast the first transatlantic radio signal...
Marconi began to work on improving his wireless for a transatlantic broadcast. Many physicists argued that radio waves traveled in straight lines, making it impossible for signals to be broadcast beyond the horizon, but Marconi believed they would follow the planet’s curvature. (In fact, the waves do travel in straight lines but bounce off the ionosphere, approximating a curve.) After failed attempts to receive a signal from England on Cape Cod, Massachusetts, Marconi decided to try a shorter distance, from Cornwall to Newfoundland.
The radio signal broadcast from Poldhu, Cornwall, was as powerful as Marconi’s team could make it—at full power, the equipment sent out sparks a foot long. Some 2,100 miles away, atop Signal Hill in St. John’s, Marconi attached an antenna first to a balloon, which blew away, and then to a kite on a 500-foot tether. On December 12, 1901, he picked up a faint three-dot sequence—the Morse Code letter “s.”
