Who sent the first transatlantic radio signal in 1901?

Guglielmo Marconi sent the first reported transatlantic radio signal in 1901.

On 12 December 1901, Marconi said he received the Morse-code letter S at St. John’s, Newfoundland, from a transmitter in Poldhu, Cornwall. The three dots were significant because they suggested that radio communication could cross the Atlantic despite Earth’s curvature.

Marconi’s work built on earlier discoveries by James Clerk Maxwell and Heinrich Hertz. Maxwell predicted electromagnetic waves mathematically, while Hertz generated and detected them experimentally. Marconi developed practical transmitting and receiving equipment and pursued long-distance wireless communication.

The precise details of the 1901 reception have been debated because the signal was weak and the receiving arrangement was basic. Nevertheless, the event is widely remembered as a landmark in radio history. It was not the first radio transmission overall, but the first famous claimed transatlantic reception.