First radio transmission sent across the Atlantic Ocean | December 12, 1901 | HISTORY

Italian physicist and radio pioneer Guglielmo Marconi succeeds in sending the first radio transmission across the Atlantic Ocean, disproving detractors who told him that the curvature of the earth would limit transmission to 200 miles or less. The message—simply the Morse-code signal for the letter “s”—traveled more than 2,000 miles from Poldhu in Cornwall, England, to Newfoundland, Canada.

Born in Bologna, Italy, in 1874 to an Italian father and an Irish mother, Marconi studied physics and became interested in the transmission of radio waves after learning of the experiments of the German physicist Heinrich Hertz. He began his own experiments in Bologna beginning in 1894 and soon succeeded in sending a radio signal over a distance of 1.5 miles. Receiving little encouragement for his experiments in Italy, he went to England in 1896. He formed a wireless telegraph company and soon was sending transmissions from distances farther than 10 miles. In 1899, he succeeded in sending a transmission across the English Channel. That year, he also equipped two U.S. ships to report to New York newspapers on the progress of the America’s Cup yacht race. That successful endeavor aroused widespread interest in Marconi and his wireless company.

Marconi’s greatest achievement came on December 12, 1901, when he received a message sent from England at St. John’s, Newfoundland. The transatlantic transmission won him worldwide fame. Ironically, detractors of the project were correct when they declared that radio waves would not follow the curvature of the earth, as Marconi believed. In fact, Marconi’s transatlantic radio signal had been headed into space when it was reflected off the ionosphere and bounced back down toward Canada. Much remained to be learned about the laws of the radio wave and the role of the atmosphere in radio transmissions, and Marconi would continue to play a leading role in radio discoveries and innovations during the next three decades.