Guglielmo Marconi Demonstrates Wireless Telegraph in the U.S.

September 30, 1899
Photo of Marconi inset, and his first transmitter incorporating a monopole antenna. It consisted of an elevated copper sheet (top) connected to a Righi spark gap (left) powered by an induction coil (center) with a telegraph key (right) to switch it on and off to spell out text messages in Morse code. Image credit: Guglielmo Marconi, Looking back over thirty years of radio, Radio Broadcast magazine, Doubleday, Page, and Co., New York, Vol. 10, No. 1, November 1926, p. 31. Public domain.
Photo of Marconi inset, and his first transmitter incorporating a monopole antenna. It consisted of an elevated copper sheet (top) connected to a Righi spark gap (left) powered by an induction coil (center) with a telegraph key (right) to switch it on and off to spell out text messages in Morse code. Image credit: Guglielmo Marconi, Looking back over thirty years of radio, Radio Broadcast magazine, Doubleday, Page, and Co., New York, Vol. 10, No. 1, November 1926, p. 31. Public domain.