Radio
Radios are communication devices that transmit or receive sound over a short distance using radio waves. They are mainly used by Humans on Earth.
Radios are usually used to play music that people can dance, sing and "fall in love" to. To Daleks, however, a radio is just noise. (DW: Evolution of the Daleks)
In 1938, Orson Welles broadcast a radio play adaptation of The War of the Worlds. (BFA: Invaders from Mars)
Circa 1969, radios manufactured by International Electromatics played a part in the Cybermen's plans to invade Earth. (DW: The Invasion)
Research stations use radio waves for tests and often transmit them out into space to search for signs of intellegent life. In the 1970s, the Nestenes attempted to materialise on Earth through radio waves at one station, but they were stopped by the Doctor and the Master. (DW: Terror of the Autons)
