page_title: History of radio
section_title: Guglielmo Marconi
hierarchical_section_title: History of radio / Summary / 19th century / Guglielmo Marconi
caption_attribution_description: English: British Post Office engineers inspect Guglielmo Marconi's wireless telegraphy (radio) equipment, during a demonstration on Flat Holm island, 13 May 1897. This was the world's first demonstration of the transmission of radio signals over open sea, between Lavernock Point and Flat Holm Island, a distance of 3 miles. In the background is the spark-gap transmitter, an induction coil (right) that generates high voltage pulses that create sparks between the balls of the Righi spark gap (left), which excites oscillating currents in a wire antenna suspended aloft by the pole seen in the center, ratiating radio waves. Information is transmitted by switching the transmitter on and off rapidly using a switch called a telegraph key (not visible), spelling out text messages in Morse code. In the foreground is the receiver. When receiving from the Lavernock station, the oscillating voltage from the antenna is applied to a coherer; a primitive radio wave detector consisting of a small tube containing two electrodes with metal filings between them. When a radio wave from a distant transmitter strikes the antenna and is applied to the coherer, the filings clump together and conduct electricity. A second circuit is attached to the coherer consisting of a battery which operates a relay (cylindrical objects at sides), which in turn sends a pulse of current to a Morse paper tape recorder (center). When a radio wave turns on the coherer, it sends a pulse to the recorder, which makes a mark on a paper tape. The Morse code message from the remote transmitter can be read from the tape, as the seated man is doing. The relays are contained within cylindrical metal shields to prevent their sparks from interfering with the sensitive coherer. Information from Retrospective:Radio waves across the water, TheFreeLibrary.com]
context_page_description: The early history of radio is the history of technology that produces and uses radio instruments that use radio waves. Within the timeline of radio, many people contributed theory and inventions in what became radio. Radio development began as "wireless telegraphy". Later radio history increasingly involves matters of broadcasting.
context_section_description: In 1894, the young Italian inventor Guglielmo Marconi began working on the idea of building long distance wireless transmission systems based on the use of Hertzian waves (radio waves), a line of inquiry that he noted other inventors did not seem to be pursuing.  Marconi read through the literature and used the ideas of others who were experimenting with radio waves but did a great deal to develop devices such as portable transmitters and receiver systems that could work over long distances, turning what was essentially a laboratory experiment into a useful communication system. By August 1895, Marconi was field testing his system but even with improvements he was only able to transmit signals up to one-half mile, a distance Oliver Lodge had predicted in 1894 as the maximum transmission distance for radio waves. Marconi raised the height of his antenna and hit upon the idea of grounding his transmitter and receiver. With these improvements the system was capable of transmitting signals up to 2 miles (3.2 km) and over hills. Marconi's experimental apparatus proved to be the first engineering-complete, commercially successful radio transmission system. Marconi's apparatus is also credited with saving the 700 people who survived the tragic Titanic disaster.
  In 1896, Marconi was awarded British patent 12039, Improvements in transmitting electrical impulses and signals and in apparatus there-for, the first patent ever issued for a Hertzian wave (radio wave) base wireless telegraphic system. In 1897, he established a radio station on the Isle of Wight, England. Marconi opened his "wireless" factory in the former silk-works at Hall Street, Chelmsford, England in 1898, employing around 60 people. Shortly after the 1900s, Marconi held the patent rights for radio. Marconi would go on to win the Nobel Prize in Physics in 1909  and be more successful than any other inventor in his ability to commercialize radio and its associated equipment into a global business. In the US some of his subsequent patented refinements (but not his original radio patent) would be overturned in a 1935 court case (upheld by the US Supreme Court in 1943).
caption: British Post Office engineers inspect Guglielmo Marconi's wireless telegraphy (radio) equipment in 1897.
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