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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.
Roosevelt used radio broadcasts to bypass the newspapers and speak directly to American citizens, conducting a series of thirty evening broadcasts to promote his views in an informal setting, in what became known as "fireside chats". Roosevelt's radio audiences averaged 18 percent during peacetime, and 58 percent during the war.
In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave ...
AM broadcasting is radio broadcasting using amplitude modulation (AM) transmissions. It was the first method developed for making audio radio transmissions, and is still used worldwide, primarily for medium wave (also known as "AM band") transmissions, but also on the longwave and shortwave radio bands.
The timeline of radio lists within the history of radio, the technology and events that produced instruments that use radio waves and activities that people undertook. Later, the history is dominated by programming and contents, which is closer to general history .
This type of radio was used exclusively for person-to-person text communication for commercial, diplomatic and military purposes and hobbyists; broadcasting did not exist. The broadcasts of live drama, comedy, music and news that characterize the Golden Age of Radio had a precedent in the Théâtrophone , commercially introduced in Paris in ...
It was at this time that Marconi began to understand that radio waves could be used for wireless communications. Marconi's early apparatus was a development of Hertz's laboratory apparatus into a system designed for communications purposes. At first Marconi used a transmitter to ring a bell in a receiver in his attic laboratory.
The first radio receivers used a coherer and sounding board, and were only able to receive continuous wave (CW) transmissions, encoded with Morse code (wireless telegraphy). Later transmission and reception of speech became possible, although Morse code transmission continued in use until the 1990s.