Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space. It does not require a medium of transport. Information is carried by systematically changing (modulating) some property of the radiated waves, such as their amplitude or their frequency. When radio waves pass an electrical conductor, the oscillating fields induce an alternating current in the conductor. This can be detected and transformed into sound or other signals that carry information.
The word 'radio' is used to describe this phenomenon, and television, radio, and cell phone transmissions are all classed as radio frequency emissions.
Before the advent of television, commercial radio broadcasts included not only news and music, but dramas, comedies, variety shows, and many other forms of entertainment. Radio was unique among dramatic presentation in that it used only sound.
The electromagnetic spectrum, extends from frequencies used in the electric power grid (at the long-wavelength end) to gamma radiation (at the short-wavelength end), covering wavelengths from thousands of kilometres down to fractions of the size of an atom. It is commonly said that EM waves beyond these limits are uncommon, although this is not actually true. The 22-year sunspot cycle, for instance, produces radiation with a period of 22 years, or a frequency of 1.4*10-9 Hz. At the other extreme, photons of arbitrarily high frequency may be produced by colliding electrons with positrons at appropriate energy. 1024 Hz photons can be produced today with man-made accelerators. In our universe the short wavelength limit is likely to be the Planck length, and the long wavelength limit is the size of the universe itself (see physical cosmology), though in principle the spectrum is infinite.
The station started at 7:00am on September 30, 1967, and succeeded the Light Programme, with some of the Light's music shows transferring to the newly-launched Radio 1. The first show however had actually started at 5.30am (on the Light programme) but continued on with Breakfast Special from Paul Hollingdale as Radio 1 split off.
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. The BBC also released albums of his BBC shows, bands like Joy Division, The Fall, Clash. Live and upfront in the BBC studio.
RadioDecember 12, 2006 "...to create, expand, and maintain wikipedia articles related to radio, including radio propagation and reception, radio programming, radio personalities, and the business of radio." (Example: Mutual Broadcasting System)
Amateur RadioAugust 24, 2006 "...to improve Wikipedia's articles related to Amateur radio, maintain the amateur radio category and its sub-categories for clean organization, and to produce and maintain templates for Amateur radio-related topic identification." (Example: Amateur radio)
PodcastingJanuary 21, 2007 "...to make Wikipedia's knowledge of notable Podcast and podcast-related information as complete as possible." (Example: Podcast)
