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

Radio waves


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.
ELF - SLF - ULF/VF - VLF - LF/LW - MW - HF/SW - VHF - UHF - SHF - EHF
Electromagnetic radio spectrum
Other types of electromagnetic radiation, with frequencies above the RF range, are infrared, visible light, ultraviolet, X-rays and gamma rays. Since the energy of an individual photon of radio frequency is too low to remove an electron from an atom, radio waves are classified as non-ionizing radiation.
Electromagnetic spectrum and diagram of radio transmission of an audio signal.

Electromagnetic radiation travels (propagates) by means of oscillating electromagnetic fields that pass through the air and the vacuum of space equally well, and does not require a medium of transport (such as the aether). When radio waves pass an electrical conductor, the oscillating electric or magnetic field (depending on the shape of the conductor) induces an alternating current and voltage in the conductor. This can be transformed into audio or other signals that carry information. The word 'radio' is used to describe this phenomenon, and television, radio, radar, and cell phone transmissions are all classed as radio frequency emissions.

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United States :: North America
Radio :: Recreation

 
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@OMGitsJessieLee question for you. Do you ever do radio shows appearances?
hatespeechradio (David Harris) Wed, 23 Dec 2009 11:41:47 -0000
@OMGitsJessieLee question for you. Do you ever do radio shows appearances?
Rob Brydan on Radio 1 is soo funny!
angiej7 (Angie Jones) Wed, 23 Dec 2009 11:41:43 -0000
Rob Brydan on Radio 1 is soo funny!
Virgin Radio Viral part 1 http://www.youtube.com/watch?v=Q3rkfS6RlKk
The4ThFloor (Bogdan Albulescu) Wed, 23 Dec 2009 11:41:34 -0000
Virgin Radio Viral part 1 http://www.youtube.com/watch?v=Q3rkfS6RlKk
Radio t sendet weiter: Radio t sendet auch im kommenden Jahr weiter. Allerdings erfolgt die Ausstrahlung des Fr.. http://bit.ly/6WdYFe
sachsenfernsehe (SACHSEN FERNSEHEN) Wed, 23 Dec 2009 11:41:26 -0000
Radio t sendet weiter: Radio t sendet auch im kommenden Jahr weiter. Allerdings erfolgt die Ausstrahlung des Fr.. http://bit.ly/6WdYFe
fajne to radio http://tinyurl.com/on6mg9 , tylko nudni ci prezenterzy, całkowita lipa
JerzyLe (Jerzy Lennert) Wed, 23 Dec 2009 11:41:25 -0000
fajne to radio http://tinyurl.com/on6mg9 , tylko nudni ci prezenterzy, całkowita lipa
RT @csinvestments: http://bit.ly/UbZQg Facing foreclosure? Gr8 NPR radio report on saving a home from foreclosure - http://ping.fm/n0a.. ...
thatrecoach (ChristopherNewell) Wed, 23 Dec 2009 11:41:18 -0000
RT @csinvestments: http://bit.ly/UbZQg Facing foreclosure? Gr8 NPR radio report on saving a home from foreclosure - http://ping.fm/n0a.. ...

 
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Stay Alert, Stay Safe, Drowsy Drivers - wilderside.ca
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