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A practical spark gap transmitter consists of these parts: [11] [13] [14] [15] A high-voltage transformer, to transform the low-voltage electricity from the power source, a battery or electric outlet, to a high enough voltage (from a few kilovolts to 75-100 kilovolts in powerful transmitters) to jump across the spark gap. The transformer ...
Spark gap tube. A spark radiates energy throughout the electromagnetic spectrum. Nowadays, this is usually regarded as illegal radio frequency interference and is suppressed, but in the early days of radio communications (1880–1920), this was the means by which radio signals were transmitted, in the unmodulated spark-gap transmitter.
A damped wave was an early method of radio transmission produced by the first radio transmitters (spark gap transmitters) which consisted of a series of damped radio waves. Information was carried on this signal by telegraphy, turning the transmitter on and off (on-off keying) to send messages in Morse code.
Continuous or ‘undamped’ waves (CW) were an important feature, since the use of damped waves from spark-gap transmitters resulted in lower transmitter efficiency and communications effectiveness, while polluting the RF spectrum with interference. Circuit of basic arc converter, from Poulsen's 1904 paper (labels added).
English: Monopole spark gap radio transmitter which Guglielmo Marconi developed in 1896. It consists of a long wire monopole antenna (A) with a spark gap (S) to ground, with an induction coil (T) powered by a battery (B) through a telegraph key (K). When the key is pressed down, the induction coil applies a string of pulses of high voltage to ...
The primitive spark-gap transmitters used until 1920 transmitted by a modulation method called damped wave. As long as the telegraph key was pressed, the transmitter would produce a string of transient pulses of radio waves which repeated at an audio rate, usually between 50 and several thousand hertz. [33]
A Marconi station built in 1902 at South Wellfleet, Cape Cod, Massachusetts (initial callsign CC, MCC 1908 to 1911, finally WCC from 1911,) transmitted its first telegraphic message via spark gap transmitter in 1903 from what is now known as the National Park Service "Marconi Area," about a mile north of the entrance to Marconi Beach.
The circuit of a coherer receiver, that recorded the received code on a Morse paper tape recorder. Unlike modern AM radio stations that transmit a continuous radio frequency, whose amplitude (power) is modulated by an audio signal, the first radio transmitters transmitted information by wireless telegraphy (radiotelegraphy), the transmitter was turned on and off (on-off keying) to produce ...