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Radio | Definition, History, Facts | Britannica From about 1920 to 1945, radio developed into the first electronic mass medium, monopolizing “the airwaves” and defining, along with newspapers, magazines, and motion pictures, an entire generation of mass culture About 1945 the appearance of television began to transform radio’s content and role
Radio technology - Wireless, Broadcasting, Communication | Britannica From 1920 onward radio made phenomenal progress through research activities in Europe, North America, and Asia The invention of the electron tube and later the transistor (1948) made possible remarkable developments
Where was radio invented? | Britannica The first practical wireless radio communication system was developed in Italy by Guglielmo Marconi Marconi built on the mathematics of physicist James Clerk Maxwell and the experiments of both Oliver Lodge and Heinrich Hertz to transmit experimental broadcasts from the lab he built in 1894 at his family’s country villa
Military communication - Electrical Signaling, Radio, Telegraph . . . Near the close of the 19th century, a new means of military signal communication made its appearance—the wireless telegraph, or radio The major powers throughout the world were quick to see the wonderful possibilities for military and naval signaling
Radio technology | History, Principles, Types, Facts | Britannica A radio wave is made up of electric and magnetic fields vibrating mutually at right angles to each other in space When these two fields are operating synchronously in time, they are said to be in time phase; i e , both reach their maxima and minima together and both go through zero together
Military communication - WWI, 1940, Technology | Britannica Despite efforts to protect the wire lines, they were frequently cut at critical times as the result of the intense artillery fire This led all the belligerents to develop and use radio (wireless) as an alternate means of communication
Edwin H. Armstrong | Radio Pioneer, FM Inventor | Britannica Invention of FM broadcasting In 1933 Armstrong secured four patents on advanced circuits that were to solve this last basic problem They revealed an entirely new radio system, from transmitter to receiver
Telegraph | Invention, History, Facts | Britannica Employing the semaphore system invented by French engineer Claude Chappe in 1791, towers spaced 5 to 10 km (3 to 6 miles) apart could relay messages cross-country in minutes
Radar - Detection, Military, Technology | Britannica Maxwell’s work led to the conclusion that radio waves can be reflected from metallic objects and refracted by a dielectric medium, just as light waves can Hertz demonstrated these properties in 1888, using radio waves at a wavelength of 66 cm (which corresponds to a frequency of about 455 MHz)