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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.
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]
1920s: Radio was first used to transmit pictures visible as television. 1926: Official Egyptian decree to regulate radio transmission stations and radio receivers. [40] Early 1930s: Single sideband (SSB) and frequency modulation (FM) were invented by amateur radio operators. By 1940, they were established commercial modes.
In the late 1980s or early 1990s, [10] [11] [12] Baylis saw a television programme about the spread of AIDS in Africa and realised that a way to halt the spread of the disease would be to educate and disseminate information by radio. [11] [13] Within 30 minutes, he had assembled the first prototype of his most well-known invention, the wind-up ...
In 1945 on the 50th anniversary of Popov's experiment the old Soviet Union made 7 May a new holiday, Radio Day, the day they claim Popov invented radio. Historians note this holiday may be more due to Cold War era politics than historical evidence. [14] [1] [3] Radio Day is still officially marked in Russia and Bulgaria.
A tuned circuit acts like a resonator, similar to a tuning fork. [31] It has a natural resonant frequency at which it oscillates. The resonant frequency of the receiver's tuned circuit is adjusted by the user to the frequency of the desired radio station; this is called tuning. The oscillating radio signal from the desired station causes the ...
In 1983, KDAY-AM became the first radio station to play wall-to-wall rap music, thanks to an ambitious new music director and some soon-to-be famous DJs. When L.A. invented rap radio: The rise of KDAY
A book published in 1946 by Charles A. Siepmann heralded FM stations as "Radio's Second Chance". [48] In late 1945, Armstrong contracted with John Orr Young, founding member of the public relations firm Young & Rubicam , to conduct a national campaign promoting FM broadcasting, especially by educational institutions.