Radios were communication device that transmitted or received sound over a distance using radio waves. They were mainly used by humans on Earth.

Radios were often used to play music that people could dance, sing and "fall in love" to. To Daleks, however, a radio was just noise. (TV: Evolution of the Daleks)

In 1938, Orson Welles broadcast a radio play adaptation of The War of the Worlds. (AUDIO: Invaders from Mars)

Circa 1969, radios manufactured by International Electromatics played a part in the Cybermen's plans to invade Earth. (TV: The Invasion)

Research stations used radio waves for tests and often transmitted them into space to search for signs of intelligent life. In the 1970s, the Nestenes tried to materialise on Earth through radio waves at one station, but they were stopped by the Third Doctor and the Master. (TV: Terror of the Autons)

Radio transmitters were a means of communication. (TV: The Sea Devils)

While in Daniel Eldred's rocket, the Second Doctor, Zoe Heriot and Jamie McCrimmon used radios to contact Earth, the Moon and one another. (TV: The Seeds of Death)

During the 22nd century Dalek invasion, the rebels received broadcasts from the Daleks via radio. (TV: The Dalek Invasion of Earth)

In the 1960s, there were a number of pirate radio ships, such as Radio Bravo, surrounding Britain. (AUDIO: Dead Air)