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File:Marconi 1897 spark gap transmitter.jpg

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English: Photo of early spark-gap radio transmitter used by Guglielmo Marconi during pioneering wireless telegraphy experiments at La Spezia, Italy in July 1897. It used an induction coil (right) powered by batteries in the box (rear) to apply pulses of high voltage to a Righi type spark gap (left), creating sparks which excited brief oscillating currents in a 75 ft. vertical antenna attached to the spark gap, ending in an 8 foot square sheet of metal. The operator turns the transmitter on and off rapidly with the telegraph key (at right) to spell out messages in Morse code. On July 18, 1897 in tests for the Italian Marine Ministry, it successfully transmitted signals 16.3 km (14 miles) from St. Bartholomew to a ship in the Sea of Spezia (source, p.337-339).
Source Downloaded 5 March 2010 from Domenico Mazzotto (1906) Wireless Telegraphy and Telephony, translated by Selimo R. Bottone, Whittaker & Co., New York, p.338, fig.236 on Google Books
Author Guglielmo Marconi
(Reusing this file)

Public domain - Marconi died in 1920


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current13:53, 5 March 2010Thumbnail for version as of 13:53, 5 March 2010429 × 286 (27 KB)Chetvorno{{Information |Description={{en|Photo of early spark-gap transmitter used by Guglielmo Marconi during pioneering wireless telegraphy experiments at La Spezia in July 1897. It used a Righi type oscillator ''(left)''.}} |Source=Downloaded 2010-03-05 f
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