Radio

Radios are communication devices that transmit or receive sound over a short distance using radio waves.

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)

A few years later, the Nestene attempted to use radio waves to materialise on Earth, but were defeated by Third Doctor and the Master. (DW: Terror of the Autons)