Marconi's first tuned transmitter, 1897.

Marconi's first tuned transmitter, 1897.

Marconi's first tuned transmitter, 1897.

'How to build a two valve set', No 13, Godfrey Philips cigarette card, 1925.

Detector used in Marconi's original transatlantic radio tests, 1901.

Detector used in Marconi's original transatlantic radio tests, 1901.

Receiver used by Marconi to detect the first transatlantic radio signals, 1901.

Four tuning forks invented by Gardiner Brown, c 1841-1930.

Radio aerials sited on the roof of the Science Museum, London, 1980s.

Radio aerials sited on the roof of the Science Museum, London, 1980s.

Radio aerials sited on the roof of the Science Museum, London, 1980s.

Western Electric 7-valve 'superhet' heterodyne radio receiver, 1924.