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1920: The first regularly operating radio station KDKA goes on air on 2 November 1920 in Philadelphia, USA. It is the first time electronics are used to transmit information and entertainment to the public at large. The same year in Germany an instrumental concert was broadcast on the radio from a long-wave transmitter in Wusterhausen.
Voltages used for electric power transmission increased throughout the 20th century. [50] The first "high voltage" AC power station, rated 4-MW 10-kV 85-Hz, was put into service in 1889 by Sebastian Ziani de Ferranti at Deptford, London. [33] The first electric power transmission line in North America operated at 4000 V.
A family listening to a crystal radio in the 1920s Greenleaf Whittier Pickard's US Patent 836,531 "Means for receiving intelligence communicated by electric waves" diagram US Bureau of Standards 1922 Circular 120 "A simple homemade radio receiving outfit" taught Americans how to build a crystal radio.
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.
Although radio was well established with United States consumers by the mid-1920s, regulation of the broadcast medium presented its own challenges. Until 1926, broadcast radio power and frequency use was regulated by the U.S. Department of Commerce, until a legal challenge rendered the agency powerless to do so. [10]
1920s: The Spanish Flu. In the fall of 1918, a mutated version of the virus that claimed its first victims in the spring made its way around the world, causing the death rate to escalate quickly ...
However, in the 1920s vacuum tube oscillators replaced it in all these applications. [89] The triode vacuum tube was a much better radio frequency current generator than the noisy, hot, ozone-producing spark, and could produce continuous waves. After this, industrial use of the Tesla coil was mainly limited to a few specialized applications ...
When someone mentions the 1920s, you might picture one of two extremes. One is the classic "Roaring 20s" image, with flappers in bucket hats and the decadence of F. Scott Fitzgerald's "The Great ...