Which inventor demonstrated the first public radio transmission across the Atlantic in 1901?

Guglielmo Marconi demonstrated the first public radio transmission across the Atlantic in 1901. On 12 December that year, he reported receiving the Morse-code letter S at St John’s, Newfoundland, from a transmitter in Cornwall, England.

Marconi’s system used spark-gap transmitters, tuned circuits, antennas, and earth connections to send wireless signals. The Atlantic experiment was important because many scientists believed radio waves might travel only along line-of-sight paths. The reported signal suggested that long-distance wireless communication was possible.

The demonstration did not transmit speech or music. It sent three simple Morse-code dots, and the weak signal was heard through headphones. Later radio systems became much more reliable and eventually carried voice, broadcasting, and data.

Marconi was not the only person contributing to radio. Nikola Tesla, Oliver Lodge, Alexander Popov, and others developed important electrical and wireless techniques. Disputes over priority continued for decades, but Marconi’s engineering work and commercial organization helped establish practical transatlantic wireless communication.