English: The Marconi Valve Tuner, an early unamplified
radio receiver manufactured by the
Marconi Company for use on ships to receive
wireless telegraphy signals. It used the
Fleming valve, the first vacuum tube, invented by
John Ambrose Fleming as a
detector to rectify the radio wave carrier and extract the Morse code "dots" and "dashes", The set had two valves (visible at top); one was a spare in case the other burned out.
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