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It was used from about 1910 in a few "superpower" longwave radiotelegraphy stations to transmit transoceanic message traffic by Morse code to similar stations all over the world. Although superseded in the early 1920s by the development of vacuum-tube transmitters , the Alexanderson alternator continued to be used until World War II .
The Morse code, as specified in the current international standard, International Morse Code Recommendation, ITU-R M.1677-1, [1] was derived from a much-improved proposal by Friedrich Gerke in 1848 that became known as the "Hamburg alphabet", its only real defect being the use of an excessively long code ( and later the equal duration code ...
Morse code abbreviations are not the same as prosigns.Morse abbreviations are composed of (normal) textual alpha-numeric character symbols with normal Morse code inter-character spacing; the character symbols in abbreviations, unlike the delineated character groups representing Morse code prosigns, are not "run together" or concatenated in the way most prosigns are formed.
The contacts could operate an audio oscillator for the study of International Morse Code (used by radio), or a sounder for the study of American Morse Code (used by railroads), or a light bulb (Aldis Lamp - used by Navy ship to ship or by Heliograph). The Instructograph was in production from about 1920 through 1983.
American Morse Code — also known as Railroad Morse—is the latter-day name for the original version of the Morse Code developed in the mid-1840s, by Samuel Morse and Alfred Vail for their electric telegraph.
SOS is a Morse code distress signal ( ), used internationally, originally established for maritime use.In formal notation SOS is written with an overscore line (SOS), to indicate that the Morse code equivalents for the individual letters of "SOS" are transmitted as an unbroken sequence of three dots / three dashes / three dots, with no spaces between the letters. [1]
During the pulses of carrier, the beat frequency is generated, while between the pulses there is no carrier so no tone is produced. Thus the BFO makes the "dots" and "dashes" of the Morse code signal audible, sounding like different length "beeps" in the speaker. A listener who knows Morse code can decode this signal to get the text message.
Telegraph Sounder. A telegraph sounder is an antique electromechanical device used as a receiver on electrical telegraph lines during the 19th century. It was invented by Alfred Vail after 1850 to replace the previous receiving device, the cumbersome Morse register [1] and was the first practical application of the electromagnet.