File:EB1911 Telegraph - Marconi transmitter and receiver.jpg
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DescriptionEB1911 Telegraph - Marconi transmitter and receiver.jpg |
English: Guglielmo Marconi's early wireless telegraphy transmitter (left) and receiver (right) from the 1890s with which he performed the first radio communication experiments.
The spark gap transmitter consisted of an induction coil (I) powered by a battery (B) connected to a spark gap (S) consisting of two metal balls with a gap of a few millimeters between them. One spark ball was connected to a monopole antenna (A1) consisting of a wire that went up to a metal sheet suspended high overhead. The other spark ball was connected to ground (E). High voltage from the induction coil charged up the antenna to a high voltage which was discharged by a spark between the spark balls. The spark excited oscillating standing waves of current in the antenna; the charge flowed back and forth between the ground and the antenna through the spark, charging the antenna alternately positive and negative. The antenna radiated this energy as radio waves. To communicate information with this device the operator tapped on the telegraph key (K) in the primary circuit of the induction coil, turning the transmitter on and off rapidly, transmitting pulses of radio waves which spelled out text messages in Morse code. |
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Date | published 1911 | ||||
Source | Encyclopædia Britannica (11th ed.), v. 26, 1911, “Telegraph,” p. 532, Fig. 38, which came from J. A. Fleming's Electric Wave Telegraphy. | ||||
Author | John Ambrose Fleming (section author) based on work by G. Marconi | ||||
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current | 15:38, 14 March 2016 | 843 × 414 (56 KB) | Library Guy (talk | contribs) | {{Information |Description ={{en|1=G. Marconi, however, made the important discovery that if his sensitive tube or coherer had one terminal attached to a metal plate lying on the earth, or buried in it, and the other to an insulated plate elevated a... |
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