Radio

The Radio Portal

Radio is the wireless transmission of signals, by modulation of electromagnetic waves with frequencies below those of light.

Radio waves are a form of electromagnetic radiation, created whenever a charged object (in normal radio transmission, an electron) accelerates with a frequency that lies in the radio frequency (RF) portion of the electromagnetic spectrum. In radio, this acceleration is caused by an alternating current in an antenna. Radio frequencies occupy the range from a few tens of hertz to a few hundred gigahertz.

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The crystal radio receiver was (also known as a crystal set) was first built circa 1900 by Greenleaf Whittier Pickard, who used crystalline minerals to detect radio signals. People first built and used simple and inexpensive crystal radio sets without batteries or electrical power. Even though vacuum tube radios were common following World War I, crystal radios remained popular, especially among beginning amateur radio enthusiasts, Boy Scouts and school children, who built crystal radios to learn basic electronics and communication.

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This diagram shows both the position of radio waves in the electromagnetic spectrum as well as how radio waves are used for communication.

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BBC 7 is a digital radio station broadcasting comedy, drama, and children's programming 24 hours a day. It is the principal broadcasting outlet for the BBC's vast archive of spoken-word entertainment. Programmes qualify for broadcast on BBC7 if they are either three years old or more, or if they have previously been broadcast twice on their original stations. Even if a programme fulfils these criteria there may be copyright issues that prevent it from appearing on BBC7.

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Radio news

• 18 March 2006
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Selected biography

John Peel, OBE (30 August 1939 – 25 October 2004), was a British disc jockey, radio presenter, and journalist.

He was one of the original DJs of Radio 1 in 1967 and the only one remaining on Radio 1 at the time of his death. Known for the extraordinary range of his taste in music and the occasional mistakes (such as playing records at the wrong speed) that marked his shows, John Peel was one of the most popular and respected DJs and broadcasters in the world. He was one of the first to play reggae and punk on British radio. His profound influence on alternative rock, pop, and dance music is widely acknowledged.

Quotes

I, madam, I made radio! So I dared! Am I mad, am I?

A palindrome by Spider Robinson.

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