blank blank
blank blank blank
Tesla Timeline of Radio blank
Home Life and Legacy Inside the Lab Tesla for Teachers Discussions Resources
blank blank blank blank
blank — Timeline of Radio —
paper top
paper left


Vert. Divider

Discovery and theory of induction by Michael Faraday and Joseph Henry.


Radio waves detected and measured by Heinrich Hertz.


Edouard Branly (1844-1940) invents a device, a "coherer," that becomes conducting in the presence of natural electric disturbances, such as lightning. (Powdered metal particles that attract one another as a field induces minute currents in them).


William Preece (1834-1913), using loops of wire several hundred feet long, detects current interruptions in one with the other..


Oliver Lodge (1851-1940) is first to employ the Branly coherer to sense "Hertzian waves" (radio waves).


Nikola Tesla is listening around New York to signals produced by high-frequency alternators at his Fifth Avenue laboratory. By tuning several sources at slightly separated frequencies, he is able to monitor the transmission at an audible beat frequency. In 1897, the year of his basic radio patent (U.S. No. 645,576), he is able to pick up a signal at West Point, 30 miles from his transmitter. (Tesla coils are in general use to power everyone's radio transmitters through the early years of the twentieth century.) He demonstrates a radio-controlled boat at Madison Square Garden in 1898.


Aleksandr Popov (1859-1906) transmits radio signals between buildings at the University of St. Petersburg.


Guglielmo Marconi (1874-1937) sends a radio signal nine miles across the Bristol Channel. In 1901, after weeks of effort, he sends a recognizable signal from England to Newfoundland, the first transatlantic wireless communication.


Ferdinand Braun (1850-1918) contributes a "sparkless" antenna to the Marconi system, and shares with Marconi the Nobel Prize for Physics in 1909.


Reginald Fessenden (1866-1932) conceives of "heterodyning" to simplify and improve radio receivers, though the principle wasn't of real use until De Forest's invention of the triode. (Two radio frequencies are beat together to give a single "intermediate" frequency.) He is first to broadcast speech and music, in 1906.


John Fleming (1849-1945) produces the first vacuum-tube "diode detector," then known as the "thermionic valve."


Lee De Forest (1873-1961) invents the three-element vacuum tube, or triode, making better signal processing and amplification possible. He called it an "audion."

Resources Index
paper right
paper top
blank stripes Screensaver Stripes Production Overview Boutique Stripes blank
Promotional support provided by: