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The first radio receivers invented by Marconi, Oliver Lodge and Alexander Popov in 1894–5 used a primitive radio wave detector called a coherer, invented in 1890 by Edouard Branly and improved by Lodge and Marconi. [1] [6] [9] [12] [16] [17] [18] The coherer was a glass tube with metal electrodes at each end, with loose metal powder between ...
In Popov's lightning detector the coherer (C) was connected to an antenna (A), and to a separate circuit with a relay (R) and battery (V) which operated an electric bell (B). The radio noise generated by a lightning strike turned on the coherer, the current from the battery was applied to the relay, closing its contacts, which applied current ...
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.
Before the discovery of electromagnetic waves and the development of radio communication, there were many wireless telegraph systems proposed and tested. [4] In April 1872 William Henry Ward received U.S. patent 126,356 for a wireless telegraphy system where he theorized that convection currents in the atmosphere could carry signals like a telegraph wire. [5]
John Hays Hammond Jr. and Sr., 1922. John Hays Hammond Jr. (April 13, 1888 – February 12, 1965) was an American inventor known as "The Father of Radio Control".Hammond's pioneering developments in electronic remote control are the foundation for all modern radio remote control devices, including modern missile guidance systems, unmanned aerial vehicles (UAVs), and the unmanned combat aerial ...
Collins became an expert in radio technology, writing many books on the subject, and conducting research on improving radio components. An unusual example were his experiments in using brain tissue to detect radio waves. [6] [7] [8] The first radio receivers prior to 1904 used a primitive device called a coherer to detect the radio waves. The ...
A galena cat's whisker detector from a 1920s crystal radio. Crystal detector (cat's whisker detector) - invented around 1904–1906 by Henry H. C. Dunwoody and Greenleaf Whittier Pickard, based on Karl Ferdinand Braun's 1874 discovery of "asymmetrical conduction" in crystals, these were the most successful and widely used detectors before the ...
(Before that, the most common type of receiver was the crystal set, although some early radios used some type of amplification through electric current or battery.) Inventions of the triode amplifier, generator, and detector enabled audio radio. Westinghouse buys DeForest's and Armstrong's patent.