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The first commercial AM Audion vacuum tube radio transmitter, built in 1914 by Lee De Forest who invented the Audion in 1906. During the mid-1920s, amplifying vacuum tubes revolutionized radio receivers and transmitters. John Ambrose Fleming developed a vacuum tube diode. Lee de Forest placed a screen, added a "grid" electrode, creating the triode.
There, Wavering and Lear together developed the first commercially successful car radio calling it the Motorola. [4] [5] Wavering and Galvin traveled around the country selling radios and teaching new dealers how to install them. [7] In 1932, Paul Galvin selected Wavering to lead Motorola's car radio and police two-way communications businesses.
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]
The next year the company used the same concept to begin establishing the first radio network. [107] The WEAF and WJZ chains. At the same time in early 1922 that it announced the beginning of advertisement-supported broadcasting, AT&T also introduced its plans for the development of the first radio network. [104]
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.
On October 19, 1985, the first Blockbuster video-rental store opened, in Dallas, Texas. The store was unique at the time because it offered customers 8,000 tapes on shelves and had a computerized ...
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
Reginald Aubrey Fessenden (October 6, 1866 – July 22, 1932) was a Canadian electrical engineer and inventor who received hundreds of patents in fields related to radio and sonar between 1891 and 1936 (seven of them after his death).