Alexander Graham Bell In 1876 Bell first demonstrated his telephone.
Henrich Hertz In 1887 Hertz, a German physicist, demonstrated how an electromagnetic wave (itself discovered by Scotsman James Clerk Maxwell) could be made to jump in the form of a spark across an air gap.
Guglielmo Marconi In 1894 Marconi, a young Italian inventor, succeeded in ringing a bell at his parents house in Bologna by sending a radio message across the room. By 1901 his signals were crossing the Atlantic.
Reginald Fessenden In 1906 US physicist Fessenden succeeded in modulating music and speech on to radio waves. The amplitude of the radio wave was altered to carry the sound — hence amplitude modulation, or AM.
Lee De Forest In 1907 De Forest, a US ...