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Monday, 19 June 2017

Radio receiver

Early developments in radio were called 'wireless telegraphy', which is why the radio used to be called the wireless.

Family listening to the first broadcasts around 1920 with a crystal receiver. The mom and dad share an earphone

President Warren Harding had the first radio installed in the White House on February 8 1922.

The UK government introduced a radio licence costing 10 shillings (50p) in 1922. Until 1971 British citizens could not officially listen to the radio in the UK without having a licence.

In 1923 a great improvement in radio receivers was advertised. The new models had a concealed speaker and eliminated the need for headphones, which were considered a nuisance because they were so heavy to wear.

By the mid-1920s, home radio receivers were becoming ubiquitous. Every home had one. Dance Bands broadcasting from Hotels and Dance Halls became a prominent feature of radio station programming.

In 1925 E. S. Ted Rogers Sr of Toronto, Canada. invented the alternating-current tube, making possible electric radios with no batteries. "All-electric" receiving sets started appearing the following year.

In 1929, American Paul Galvin, the head of Galvin Manufacturing Corporation, invented the first car radio. Consumers had to purchase the radios separately as they were not available from automobile manufacturers. Galvin coined the name Motorola for the company's new products, combining the idea of motion and radio.

The first transistor radio, the Regency TR-1, was announced on October 18, 1954. Two companies working together, Texas Instruments of Dallas, Texas and Industrial Development Engineering Associates (I.D.E.A.) of Indianapolis, Indiana, were behind its unveiling. The Regency TR-1 was put on sale in November 1954, and was the first practical transistor radio made in any significant numbers.

Regency TR-1 transistor radio

In 1991, the British inventor Trevor Baylis saw a television program about AIDS in Africa. He was horrified by reports from the dark continent that safe-sex education wasn't getting through, but intrigued that one way to stop the spread of AIDS was for people to hear educational information on the radio. So Baylis devised a contraption that didn't need batteries and ran off an internal generator powered by a mainspring wound by a hand crank. After Baylis demonstrated his wind-up radio to Nelson Mandela, it was distributed all over Africa.

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