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issues a lifetime commercial
Radiotelegraph Operator License. This requires passing a simple written test on regulations, a more complex written exam on technology, and demonstrating Morse reception at 20 words per minute plain language and 16 wpm code groups. (Credit is given for amateur extra class
814:
in 1932. When the United States entered World War I, private radiotelegraphy stations were prohibited, which put an end to several pioneers' work in this field. By the 1920s, there was a worldwide network of commercial and government radiotelegraphic stations, plus extensive use of radiotelegraphy by
328:
made in 2021. Since 2003, knowledge of Morse code and wireless telegraphy has no longer been required to obtain an amateur radio license in many countries, it is, however, still required in some countries to obtain a licence of a different class. As of 2021, licence Class A in
Belarus and Estonia, or
582:
of constant amplitude. Since all the radio wave's energy was concentrated at a single frequency, CW transmitters could transmit further with a given power, and also caused virtually no interference to transmissions on adjacent frequencies. The first transmitters able to produce continuous wave were
475:
linking distant stations was very expensive, and wires could not reach some locations such as ships at sea. Inventors realized if a way could be found to send electrical impulses of Morse code between separate points without a connecting wire, it could revolutionize communications.
507:
and thus fell under the Post Office monopoly. This did not seem to hold back
Marconi. After Marconi sent wireless telegraphic signals across the Atlantic Ocean in 1901, the system began being used for regular communication including ship-to-shore and ship-to-ship communication.
794:
58:
was also used for other experimental technologies for transmitting telegraph signals without wires. In radiotelegraphy, information is transmitted by pulses of radio waves of two different lengths called "dots" and "dashes", which spell out text messages, usually in
490:
worked on adapting the newly discovered phenomenon of radio waves to communication, turning what was essentially a laboratory experiment up to that point into a useful communication system, building the first radiotelegraphy system using them. Preece and the
754:
range and can be heard in the receiver's earphones. During the "dots" and "dashes" of the signal, the beat tone is produced, while between them there is no carrier so no tone is produced. Thus the Morse code is audible as musical "beeps" in the earphones.
535:, which turned the transmitter on and off, producing short ("dot") and long ("dash") pulses of radio waves, groups of which comprised the letters and other symbols of the Morse code. At the receiver, the signals could be heard as musical "beeps" in the
766:. After this time BFOs were a standard part of radiotelegraphy receivers. Each time the radio was tuned to a different station frequency, the BFO frequency had to be changed also, so the BFO oscillator had to be tunable. In later
567:, meaning that the radio signal was not a single frequency but occupied a wide band of frequencies. Damped wave transmitters had a limited range and interfered with the transmissions of other transmitters on adjacent frequencies.
113:
Radiotelegraphy was used for long-distance person-to-person commercial, diplomatic, and military text communication throughout the first half of the 20th century. It became a strategically important capability during the two
460:, a device that would make a "click" sound when it received each pulse of current. The operator at the receiving station who knew Morse code would translate the clicking sounds to text and write down the message. The
2418:
Wireless
Telegraphy and High Frequency Electricity: A Manual Containing Detailed Information for the Construction of Transformers, Wireless Telegraph and High Frequency Apparatus, with Chapters on Their Theory and
334:
940:
748:
265:
Radiotelegraphy is obsolete in commercial radio communication, and its last civilian use, requiring maritime shipping radio operators to use Morse code for emergency communications, ended in 1999 when the
781:
because they were cheap. CW became the standard method of transmitting radiotelegraphy by the 20s, damped wave spark transmitters were banned by 1930 and CW continues to be used today. Even today most
928:
559:. 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
467:
By the 1860s, the telegraph was the standard way to send most urgent commercial, diplomatic and military messages, and industrial nations had built continent-wide telegraph networks, with
913:
2537:... The A B C of Wireless Telegraphy: A Plain Treatise on Hertzian Wave Signaling; Embracing Theory, Methods of Operation, and how to Build Various Pieces of the Apparatus Employed
2025:
839:, using radio signals, which was developed in the 1930s and was for many years the only reliable form of communication between many distant countries. The most advanced standard,
1492:
539:
by the receiving operator, who would translate the code back into text. By 1910, communication by what had been called "Hertzian waves" was being universally referred to as "
650:
420:
Example of transatlantic radiotelegraph message recorded on paper tape at RCA's New York receiving center in 1920. The translation of the Morse code is given below the tape.
677:
563:. In a receiver's earphone, this sounded like a musical tone, rasp or buzz. Thus the Morse code "dots" and "dashes" sounded like beeps. Damped wave had a large frequency
2189:
853:
Today, due to more modern text transmission methods, Morse code radiotelegraphy for commercial use has become obsolete. On shipboard, the computer and satellite-linked
606:
However, the radio receivers used for damped wave could not receive continuous wave. Because the CW signal produced while the key was pressed was just an unmodulated
337:
Class 1 licence in
Ireland, and Class 1 in Russia, both of which require proficiency in wireless telegraphy, offer additional privileges: a shorter and more desirable
2446:
807:
90:
used radiotelegraphy. It continued to be the only type of radio transmission during the first few decades of radio, called the "wireless telegraphy era" up until
1217:
Individual nations enforce this prohibition in their communication laws. In the United States, this is the
Federal Communications Commission (FCC) regulations:
610:, it made no sound in a receiver's earphones. To receive a CW signal, some way had to be found to make the Morse code carrier wave pulses audible in a receiver.
499:
from 1896. Preece had become convinced of the idea through his experiments with wireless induction. However, the backing was withdrawn when
Marconi formed the
254:'s earphone or speaker as a sequence of buzzes or beeps, which is translated back to text by an operator who knows Morse code. With automatic radiotelegraphy
3674:
3646:
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271:
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This problem was solved by
Reginald Fessenden in 1901. In his "heterodyne" receiver, the incoming radiotelegraph signal is mixed in the receiver's
3756:
3668:
500:
3663:
3653:
3633:
3435:
2215:
1958:
1799:
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900:, generally credited as first to develop practical radio-based wireless telegraphy communication, in 1901 with one of his first transmitters
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811:
575:
173:
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1312:
282:, still exists in California, run primarily as a museum by volunteers, and occasional contacts with ships are made. In a minor legacy use,
1678:
1552:
312:, or just CW. A 2021 analysis of over 700 million communications logged by the Club Log blog, and a similar review of data logged by the
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3504:
2022:
1914:
267:
2190:
Title 47 –Telecommunication
Chapter I – Federal Communications Commission Subchapter A – General Part 13 – Commercial Radio Operators
3430:
200:
and tended to interfere with other transmissions. This type of emission was banned by 1934, except for some legacy use on ships. The
1503:
329:
the
General class in Monaco, or Class 1 in Ukraine require Morse proficiency to access the full amateur radio spectrum including the
320:
communication, accounting for nearly 20% of contacts. This makes it more popular than voice communication, but not as popular as the
3524:
1688:
1349:
1322:
1295:
876:
823:. Wireless telegraphy continued to be used for private person-to-person business, governmental, and military communication, such as
690:
24:
2352:
Wireless Telegraphy and Wireless Telephony: An Understandable Presentation of the Science of Wireless Transmission of Intelligence
2136:
278:
operators, and military services require signalmen to be trained in Morse code for emergency communication. A CW coastal station,
118:
since a nation without long-distance radiotelegraph stations could be isolated from the rest of the world by an enemy cutting its
75:
the pulses are audible in the receiver's speaker as beeps, which are translated back to text by an operator who knows Morse code.
3309:
2857:
2659:
798:
In World War I balloons were used as a quick way to raise wire antennas for military field radiotelegraph stations. Balloons at
1366:
1112:
Bondyopadhyay, Prebir K. (1995). "Guglielmo Marconi – The father of long distance radio communication – An engineer's tribute".
3420:
1020:
3415:
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2236:
1219:
1052:
1022:
Hawkins' Electrical Dictionary: A cyclopedia of words, terms, phrases and data used in the electric arts, trades and sciences
777:
Continuous-wave vacuum tube transmitters replaced the other types of transmitter with the availability of power tubes after
2137:"Requirements for Telex and Gentex operation to be met by synchronous multiplex equipment described in recommendation R.44"
1096:
3440:
564:
197:
126:. It is also taught by the military for use in emergency communications. However, commercial radiotelegraphy is obsolete.
106:) to be transmitted by radio. Beginning about 1908, powerful transoceanic radiotelegraphy stations transmitted commercial
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2636:
3715:
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2683:
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After 1905 new types of radiotelegraph transmitters were invented which transmitted code using a new modulation method:
354:
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networks (RTTY). Morse code radiotelegraphy was gradually replaced by radioteletype in most high volume applications by
3705:
3212:
2652:
313:
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The BFO was rare until the invention in 1913 of the first practical electronic oscillator, the vacuum tube feedback
3564:
3486:
3425:
3132:
398:
Typical commercial radiotelegraphy receiver from the first decade of the 20th century. The "dots" and "dashes" of
456:
to the telegraph line, sending current down the wire. At the receiving office, the current pulses would operate a
3336:
3297:
3142:
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2904:
2731:
1577:"History of the Atlantic Cable & Submarine Telegraphy - Frank Leslie's Illustrated Newspaper 1858 Cable News"
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was used as the return path for current in the telegraph circuit, to avoid having to use a second overhead wire.
283:
216:
119:
1478:
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2711:
2429:
Poincaré, Lucien (28 February 2005) . "Chapter VII: A Chapter in the History of Science: Wireless telegraphy".
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177:
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771:
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220:
2593:
A History of Wireless Telegraphy, 1838–1899: including some bare-wire proposals for subaqueous telegraphs
2550:
A History of Wireless Telegraphy, 1838-1899: Including Some Bare-wire Proposals for Subaqueous Telegraphs
543:", and the term wireless telegraphy has been largely replaced by the more modern term "radiotelegraphy".
3358:
3162:
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3047:
3027:
2949:
2837:
2758:
2283:
2204:
Sarkar, T. K.; Mailloux, Robert; Oliner, Arthur A.; Salazar-Palma, M.; Sengupta, Dipak L. (2006-01-30).
2172:
2091:
1753:
earlyradiohistory.us, United States Early Radio History, Thomas H. White, section 22, Word Origins-Radio
759:
618:
552:
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453:
189:
47:
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as emission type A1A). As long as the telegraph key was pressed, the transmitter produced a continuous
215:(CW), which is still used today. To receive CW transmissions, the receiver requires a circuit called a
392:
3272:
3232:
3202:
2959:
2894:
2785:
1654:
Ingenious Ireland: A County-by-County Exploration of the Mysteries and Marvels of the Ingenious Irish
967:
750:. If the BFO frequency is near enough to the radio station's frequency, the beat frequency is in the
495:(GPO) in Britain at first supported and gave financial backing to Marconi's experiments conducted on
461:
95:
1601:
628:
483:
in 1887, and the development of practical radiotelegraphy transmitters and receivers by about 1899.
145:
Illustration from 1912 of a radiotelegraph operator on a ship sending an emergency SOS call for help
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1939:
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774:(IF) produced by the superheterodyne's detector. Therefore, the BFO could be a fixed frequency.
2249:
1652:
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819:) began to displace radiotelegraphy by the 1920s for many applications, making possible radio
799:
520:
487:
457:
204:(valve) transmitters which came into use after 1920 transmitted code by pulses of unmodulated
151:
87:
1922:
1789:
424:
Efforts to find a way to transmit telegraph signals without wires grew out of the success of
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networks, the first instant telecommunication systems. Developed beginning in the 1830s, a
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1999:
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2067:"Broadcasting | Definition, History, Types, Systems, Examples, & Facts | Britannica"
1431:
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German officers and troops manning a wireless field telegraph station during World War I
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816:
680:
603:. These slowly replaced the spark transmitters in high power radiotelegraphy stations.
472:
437:
429:
330:
305:
251:
99:
83:
72:
815:
ships for both commercial purposes and passenger messages. The transmission of sound (
364:
78:
Radiotelegraphy was the first means of radio communication. The first practical radio
3740:
3529:
3302:
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3207:
3097:
3092:
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2889:
2748:
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1220:"Section 2.201: Emission, modulation, and transmission characteristics, footnote (f)"
977:
832:
584:
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504:
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317:
290:
275:
239:
224:
169:
123:
64:
1074:
American Telegraphy and Encyclopedia of the Telegraph: Systems, Apparatus, Operation
246:
of different lengths called "dots" and "dashes", which encode characters of text in
3407:
3247:
3192:
3122:
3087:
3022:
2921:
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2430:
2390:
2231:. Science, culture and society. New York London Sydney Toronto: J. Wiley and sons.
1129:
820:
607:
528:
471:
allowing telegraph messages to bridge oceans. However installing and maintaining a
243:
228:
208:
103:
503:. GPO lawyers determined that the system was a telegraph under the meaning of the
2575:
2535:
2462:. University of California. London, New York and Bombay, Longmans, Green, and Co.
2416:
2363:
2350:
2311:
2205:
1224:
Code of Federal Regulations, Title 47, Chapter I, Subchapter A, Part 2, Subpart C
1144:
999:
3607:
3257:
3167:
3152:
3112:
3072:
2931:
1975:"Superheterodyne reception | Radio waves, Frequency, Amplification | Britannica"
920:
836:
778:
556:
259:
255:
242:, which turns the radio transmitter on and off, producing pulses of unmodulated
201:
193:
91:
79:
68:
3612:
3319:
3017:
2926:
2882:
2852:
2830:
2820:
2795:
2265:
1680:
Icons of the invention: the makers of the modern world from Gutenberg to Gates
847:
684:
516:
480:
449:
399:
247:
205:
185:
60:
43:
28:
2273:
1287:
Electrical, Electronics and Computer Engineering for Scientists and Engineers
1121:
3597:
3062:
2877:
1846:
579:
536:
383:
338:
298:
115:
806:
The International Radiotelegraph Union was unofficially established at the
341:
in both countries, and the right to use a higher transmit power in Russia.
2042:
1752:
1719:
1627:
Icons of Invention: The Makers of the Modern World from Gutenberg to Gates
3592:
3582:
3499:
3324:
3147:
824:
107:
2524:
Wireless Telegraphy: Its Origins, Development, Inventions, and Apparatus
2408:. University of Wisconsin - Madison. New York, D. Van Nostrand company;
2329:. University of California Libraries. New York, D. Van Nostrand company.
1732:
770:
receivers from the 1930s on, the BFO signal was mixed with the constant
3587:
3572:
2475:. University of Michigan. London ; New York : Cassell and Co.
1876:
Transactions of the International Electrical Congress, St. Louis, 1904
3617:
3577:
2899:
2691:
2644:
2326:
Radiodynamics, the wireless control of torpedoes and other mechanisms
2004:
Circuit Board Fabrication and PCB Assembly Turnkey Services - WellPCB
1528:"1830s – 1860s: Telegraph | Imagining the Internet | Elon University"
1398:
448:, creating pulses of electric current which spelled out a message in
441:
316:, both show that wireless telegraphy is the 2nd most popular mode of
235:
63:. In a manual system, the sending operator taps on a switch called a
2250:"A technological survey of broadcasting's "pre-history," 1876–1920"
3602:
3539:
2847:
1733:"Marconi at Mizen Head Visitor Centre Ireland Visitor Attractions"
854:
840:
793:
560:
540:
432:
was a person-to-person text message system consisting of multiple
415:
139:
19:
18:
2622:
919:
German troops erecting a wireless field telegraph station during
835:
networks. The ultimate implementation of wireless telegraphy was
617:
crystal or vacuum tube with a constant sine wave generated by an
3544:
2580:. American Institute of Electrical Engineers. 1919. p. 306.
1432:"ARRL Letter, FT8 Accounts for Nearly Two-Thirds of HF Activity"
857:
system have largely replaced Morse as a means of communication.
786:
produced for use in shortwave communication stations have BFOs.
2648:
1169:"Zimmermann Telegram | Facts, Text, & Outcome | Britannica"
1101:. Washington D.C.: U.S. Bureau of the Census. pp. 118–119.
110:
traffic between countries at rates up to 200 words per minute.
2790:
2577:
Transactions of the American Institute of Electrical Engineers
2514:. University of Michigan. New York, McGraw publishing company.
2362:
Massie, Walter Wentworth; Underhill, Charles Reginald (1908).
1000:
Transactions of the American Institute of Electrical Engineers
743:{\displaystyle f_{\text{BEAT}}=|f_{\text{IN}}-f_{\text{BFO}}|}
440:. To send a message, an operator at one office would tap on a
321:
2488:. University of Michigan. New York, D. Van Nostrand company;
1367:"Why the Navy Sees Morse Code as the Future of Communication"
687:) at the difference between the two frequencies is produced:
479:
The successful solution to this problem was the discovery of
234:
In manual radiotelegraphy the sending operator manipulates a
1270:
The History of Communications - Electronics in the U.S. Navy
164:
Wireless telegraphy or radiotelegraphy, commonly called CW (
1915:"Carrier wave with no modulation transports no information"
996:
Wireless Telephony – By R. A. Fessenden (Illustrated.)
1253:
Contact at Sea: A History of Maritime Radio Communications
555:
used until 1920 transmitted by a modulation method called
531:). Instead, the operator would send the text message on a
486:
Over several years starting in 1894, the Italian inventor
250:. At the receiving location, Morse code is audible in the
2349:
Ashley, Charles Grinnell; Hayward, Charles Brian (1912).
1226:. US Government Publishing Office website. 1 October 2007
1953:. The Antique Wireless Association, Inc.: 287–289 2009.
1145:"Technology You Didn't Know Still Existed: The Telegram"
511:
With this development, wireless telegraphy came to mean
71:
on and off, producing the pulses of radio waves. At the
2000:"Beat Frequency Oscillator- Principle and Applications"
1872:"System for producing continuous electric oscillations"
1412:"Club Log activity report – 2021 update | G7VJR's Blog"
1002:. New York: American Institute of Electrical Engineers.
679:. In the detector the two frequencies subtract, and a
587:(Poulsen arc) transmitter, invented by Danish engineer
168:), ICW (interrupted continuous wave) transmission, or
2511:
Wireless telegraphy; its history, theory and practice
2365:
Wireless Telegraphy and Telephony Popularly Explained
1712:
The Electric Telegraph: A Social and Economic History
1462:"CEPT Radio Amateur Licence Recommendation T/R 61-01"
994:
American Institute of Electrical Engineers. (1908). "
846:, automated both routing and encoding of messages by
693:
658:
631:
157:
Modern amateur radio operator transmitting Morse code
2342:. University of Michigan. New York : Macmillan.
2300:
The Encyclopædia Britannica: Submarine Mines-Tom-tom
1493:"Условия использования выделенных полос радиочастот"
3626:
3563:
3485:
3449:
3406:
3347:
3281:
2990:
2682:
1878:. Vol. 2. J.B. Lyon Company. pp. 963–971.
1606:
American Association for the Advancement of Science
964:
originally American Telephone and Telegraph Company
880:licenses earned under the old 20 wpm requirement.)
2469:Simmons, Harold H. (1909). "Wireless telegraphy".
2336:Thompson, Silvanus P. (Silvanus Phillips) (1915).
2023:ICAO and the International Telecommunication Union
1036:
742:
671:
644:
527:used until World War I, could not transmit voice (
2561:"Telegraphing across space, Electric wave method"
2508:Collins, A. Frederick (Archie Frederick) (1905).
652:is offset from the radio transmitter's frequency
297:service still transmit their one to three letter
1890:"Milestones:Alexanderson Radio Alternator, 1904"
1788:Siwiak, Kazimierz; McKeown, Debra (2004-06-07).
1039:Merriam-Webster's Collegiate Dictionary: 11th Ed
184:method. It was transmitted by several different
2527:. University of California. D. Van Nostrand Co.
2339:Elementary lessons in electricity and magnetism
1284:Krishnamurthy, K. A.; Raghuveer, M. R. (2007).
1098:Special Reports: Telephones and Telegraphs 1902
452:. When the key was pressed, it would connect a
2553:. University of Michigan. Dodd, Mead & co.
1602:"Heinrich Hertz and electromagnetic radiation"
950:, using a hydrogen balloon to lift the antenna
2660:
2501:. University of Michigan. Whittaker & Co.
808:first International Radiotelegraph Convention
8:
2382:. Simmons-Boardman Publishing Company. 1911.
2043:"13. Radio During World War One (1914-1919)"
1245:
1243:
1241:
3675:Global telecommunications regulation bodies
1095:Steuart, William Mott; et al. (1906).
3711:
2667:
2653:
2645:
2459:The principles of electric wave telegraphy
2445:: CS1 maint: location missing publisher (
1551:Laboratory, National High Magnetic Field.
188:methods during its history. The primitive
2113:"BT Museum Memorial Pages - Telegraphy 2"
1553:"Morse Telegraph – 1844 - Magnet Academy"
1344:. Technical Publications. p. 12.55.
1077:. New York: Maver Publishing Co. p.
868:(CW) radiotelegraphy is regulated by the
735:
729:
716:
707:
698:
692:
663:
657:
636:
630:
324:digital mode, which accounted for 60% of
1502:(in Russian). 2015-10-16. Archived from
1114:25th European Microwave Conference, 1995
625:(BFO). The frequency of the oscillator
436:linked by an overhead wire supported on
402:were recorded in ink on paper tape by a
308:world-wide, who commonly refer to it as
2395:. London, New York, Whittaker & co.
2229:Syntony and spark: the origins of radio
1191:
1189:
1011:
887:
501:Wireless Telegraph & Signal Company
2438:
2392:Wireless telegraphy and Hertzian waves
2248:Sivowitch, Elliot N. (December 1970).
2092:"Typing in Airplane Received by Radio"
1338:Godse, Atul P.; Bakshi, U. A. (2009).
1314:Basic Radio: Principles and Technology
1290:. New Age International. p. 375.
519:transmitted by radio waves. The first
370:British Post Office engineers inspect
260:International Telegraph Alphabet No. 2
219:(BFO). The third type of modulation,
2376:"Developments in wireless telegraphy"
2141:International Telecommunication Union
1934:
1932:
1840:
1838:
1813:
1811:
1456:
1454:
1452:
1025:. Theodore Audel and Co. p. 498.
870:International Telecommunication Union
812:International Telecommunication Union
576:International Telecommunication Union
274:system. However it is still used by
174:International Telecommunication Union
122:. Radiotelegraphy remains popular in
7:
3721:
2355:. American School of Correspondence.
2323:Miessner, Benjamin Franklin (1916).
1479:"Amateur Station Licence Guidelines"
1388:Morse code training in the Air Force
1043:. Merriam-Webster Co. 2004. p.
258:at both ends use a code such as the
42:is transmission of text messages by
2177:International Maritime Organization
2159:International Maritime Organization
1657:. Simon and Schuster. p. 313.
304:Radiotelegraphy is popular amongst
268:International Maritime Organization
2485:A handbook of wireless telegraphy;
2472:Outlines of electrical engineering
2405:A handbook of wireless telegraphy;
2288:The New International Encyclopædia
1256:. The Gregg Press. pp. 26–30.
14:
2498:Wireless Telegraphy and Telephony
2432:The New Physics and Its Evolution
1600:Edwards, Steven A. (2012-10-12).
877:Federal Communications Commission
810:in 1906, and was merged into the
3720:
3710:
3701:
3700:
3689:
3310:Free-space optical communication
2616:The Story of Wireless Telegraphy
2415:Twining, Harry La Verne (1909).
2380:International Marine Engineering
2313:Textebook on wireless telegraphy
2290:. Dodd, Mead. 1922. p. 637.
1410:Wells, Michael (27 March 2021).
939:
927:
912:
890:
391:
363:
270:switched to the satellite-based
150:
138:
1791:Ultra-wideband Radio Technology
1630:. ABC-CLIO. 2009. p. 162.
284:VHF omnidirectional range (VOR)
31:transmitting by radiotelegraphy
3757:Wireless communication systems
2482:Murray, James Erskine (1907).
2456:Fleming, John Ambrose (1908).
2402:Murray, James Erskine (1907).
2389:Bottone, Selimo Romeo (1910).
1500:General Radio Frequency Centre
1481:. 2018-04-16. pp. 17, 32.
1197:"Maritime Morse Is Tapped Out"
736:
708:
645:{\displaystyle f_{\text{BFO}}}
54:. Before about 1910, the term
1:
2638:Principles of Radiotelegraphy
2630:Principles of Radiotelegraphy
2521:Charles Henry Sewall (1903).
672:{\displaystyle f_{\text{IN}}}
3696:Telecommunication portal
3477:Telecommunications equipment
2567:. Biggs & Company. 1898.
2540:. Bubier publishing Company.
1365:Maxey, Kyle (17 July 2017).
1250:Schroeder, Peter B. (1967).
1199:. Wired website. 6 July 1998
1143:Spencer, Luke (2015-06-02).
872:(ITU) as emission type A1A.
355:History of telecommunication
192:used until 1920 transmitted
3747:History of radio technology
3213:Alexander Stepanovich Popov
2623:Sparks Telegraph Key Review
2227:Aitken, Hugo G. J. (1976).
1894:IEEE Global History Network
1071:Maver, William Jr. (1903).
314:American Radio Relay League
3773:
2917:Telecommunications history
2547:John Joseph Fahie (1900).
2495:Domenico Mazzotto (1906).
2368:. D. Van Nostrand Company.
2303:. At the University Press.
1870:Poulsen, Valdemar (1905).
1847:"Emissions Designator A1A"
1765:"Spark Transmitter Basics"
1714:, David and Charles, 1973
1369:. Engineering. com website
1019:Hawkins, Nehemiah (1910).
469:submarine telegraph cables
348:
120:submarine telegraph cables
94:, when the development of
27:radio operator in 1943 in
3684:
3525:Public Switched Telephone
3337:telecommunication circuit
3298:Fiber-optic communication
3043:Francis Blake (telephone)
2838:Optical telecommunication
2266:10.1080/08838157009363620
1273:. U.S. Navy. p. 509.
829:diplomatic communications
623:beat frequency oscillator
621:in the receiver called a
595:, invented 1906–1912 by
262:and produced typed text.
223:(FSK) was used mainly by
217:beat frequency oscillator
86:invented in 1894–1895 by
3436:Orbital angular-momentum
2873:Satellite communications
2712:Communications satellite
2534:Trevert, Edward (1904).
2310:Stanley, Rupert (1919).
1794:. Wiley. pp. 1–20.
1651:Mulvihill, Mary (2003).
1122:10.1109/EUMA.1995.337090
948:German South West Africa
946:Mobile radio station in
784:communications receivers
574:(CW) (designated by the
178:emission type A1A or A2A
172:, and designated by the
3315:Molecular communication
3138:Gardiner Greene Hubbard
2967:Undersea telegraph line
2702:Cable protection system
2565:The Electrical Engineer
2297:Chisholm, Hugh (1911).
2254:Journal of Broadcasting
2032:– ICAO official website
1998:Lu, Emma (2022-02-25).
1317:. Newnes. p. 134.
973:Imperial Wireless Chain
593:Alexanderson alternator
16:Method of communication
3457:Communication protocol
3243:Charles Sumner Tainter
3058:Walter Houser Brattain
3003:Edwin Howard Armstrong
2811:Information revolution
2173:"Introduction/History"
1267:Howeth, L. S. (1963).
803:
772:intermediate frequency
744:
673:
646:
553:spark-gap transmitters
525:spark gap transmitters
421:
326:amateur radio contacts
221:frequency-shift keying
196:, which had very wide
190:spark-gap transmitters
32:
3431:Polarization-division
3163:Narinder Singh Kapany
3128:Erna Schneider Hoover
3048:Jagadish Chandra Bose
3028:Alexander Graham Bell
2759:online video platform
2604:1901 (second edition)
2284:"Wireless telegraphy"
2155:"Radiocommunications"
1940:"Heterodyne receiver"
1823:TheFreeDictionary.com
797:
745:
674:
647:
619:electronic oscillator
419:
349:Further information:
333:(HF) bands. Further,
48:electrical telegraphy
22:
3273:Vladimir K. Zworykin
3233:Almon Brown Strowger
3203:Charles Grafton Page
2858:Prepaid mobile phone
2786:Electrical telegraph
2599:1899 (first edition)
2047:earlyradiohistory.us
1083:wireless telegraphy.
1059:wireless telegraphy.
984:References and notes
968:Electrical telegraph
962:AT&T Corporation
691:
656:
629:
96:amplitude modulation
3223:Johann Philipp Reis
2982:Wireless revolution
2944:The Telephone Cases
2801:Hydraulic telegraph
2611:Alfred Thomas Story
2591:John Joseph Fahie,
2574:"Radio telephony".
2207:History of Wireless
2117:www.samhallas.co.uk
1919:University of Texas
1710:Kieve, Jeffrey L.,
1311:Poole, Ian (1998).
831:, and evolved into
493:General Post Office
182:radio communication
56:wireless telegraphy
36:Wireless telegraphy
3421:Frequency-division
3398:Telephone exchange
3268:Charles Wheatstone
3198:Jun-ichi Nishizawa
3173:Innocenzo Manzetti
3108:Reginald Fessenden
2843:Optical telegraphy
2676:Telecommunications
2316:. Longmans, Green.
2099:The New York Times
2071:www.britannica.com
2028:2018-11-06 at the
1979:www.britannica.com
1683:. ABC-CLIO. 2009.
1581:atlantic-cable.com
1557:nationalmaglab.org
1173:www.britannica.com
804:
740:
669:
642:
601:Ernst Alexanderson
597:Reginald Fessenden
521:radio transmitters
426:electric telegraph
422:
351:Invention of radio
33:
3734:
3733:
3472:Store and forward
3467:Data transmission
3381:Network switching
3332:Transmission line
3178:Guglielmo Marconi
3143:Internet pioneers
3008:Mohamed M. Atalla
2977:Whistled language
2627:Cyril M. Jansky,
2217:978-0-471-78301-5
1960:978-0-9741994-1-2
1819:"continuous wave"
1801:978-0-470-85931-5
1664:978-0-684-02094-5
1637:978-0-313-34743-6
1399:Coast Station KSM
1341:Basic Electronics
898:Guglielmo Marconi
800:Tempelhofer Field
732:
719:
701:
666:
639:
591:in 1903, and the
488:Guglielmo Marconi
458:telegraph sounder
434:telegraph offices
88:Guglielmo Marconi
3764:
3724:
3723:
3714:
3713:
3704:
3703:
3694:
3693:
3692:
3565:Notable networks
3555:Wireless network
3495:Cellular network
3487:Types of network
3462:Computer network
3349:Network topology
3263:Thomas A. Watson
3118:Oliver Heaviside
3103:Philo Farnsworth
3078:Daniel Davis Jr.
3053:Charles Bourseul
3013:John Logie Baird
2722:Data compression
2717:Computer network
2669:
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2011:
2010:
1995:
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1965:
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1936:
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1926:
1921:. Archived from
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802:, Germany, 1908.
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589:Valdemar Poulsen
395:
367:
295:radio navigation
293:in the aviation
154:
142:
67:which turns the
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3183:Robert Metcalfe
3038:Tim Berners-Lee
2986:
2806:Information Age
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2200:
2198:Further reading
2195:
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2049:
2041:
2040:
2036:
2030:Wayback Machine
2021:
2017:
2008:
2006:
1997:
1996:
1992:
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1981:
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1771:
1769:home.freeuk.net
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1736:
1735:. Mizenhead.net
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1137:
1116:. p. 879.
1111:
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991:
986:
958:
951:
944:
935:
932:
923:
917:
908:
895:
886:
866:Continuous wave
863:
850:transmissions.
792:
768:superheterodyne
764:Edwin Armstrong
752:audio frequency
725:
712:
694:
689:
688:
659:
654:
653:
632:
627:
626:
580:sinusoidal wave
572:continuous wave
549:
513:radiotelegraphy
497:Salisbury Plain
438:telegraph poles
414:
413:
412:
411:
410:
404:siphon recorder
396:
388:
387:
374:'s transmitter
368:
357:
347:
310:continuous wave
301:in Morse code.
213:continuous wave
166:continuous wave
162:
161:
160:
159:
158:
155:
147:
146:
143:
132:
102:allowed sound (
46:, analogous to
40:radiotelegraphy
17:
12:
11:
5:
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3768:
3760:
3759:
3754:
3749:
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3447:
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3416:Space-division
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3404:
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3275:
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3265:
3260:
3255:
3253:Camille Tissot
3250:
3245:
3240:
3235:
3230:
3228:Claude Shannon
3225:
3220:
3218:Tivadar Puskás
3215:
3210:
3205:
3200:
3195:
3190:
3188:Antonio Meucci
3185:
3180:
3175:
3170:
3165:
3160:
3158:Charles K. Kao
3155:
3150:
3145:
3140:
3135:
3133:Harold Hopkins
3130:
3125:
3120:
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3110:
3105:
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3090:
3085:
3080:
3075:
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3060:
3055:
3050:
3045:
3040:
3035:
3033:Emile Berliner
3030:
3025:
3020:
3015:
3010:
3005:
3000:
2994:
2992:
2988:
2987:
2985:
2984:
2979:
2974:
2972:Videotelephony
2969:
2964:
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2957:
2947:
2940:
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2924:
2919:
2914:
2909:
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2887:
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2870:
2868:Radiotelephone
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2845:
2840:
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2756:
2754:Internet video
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2586:External links
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2015:
1990:
1966:
1959:
1947:The AWA Review
1928:
1925:on 2008-04-14.
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926:
924:
918:
911:
909:
904:and receivers
896:
889:
885:
882:
862:
859:
817:radiotelephony
791:
788:
738:
728:
724:
715:
710:
706:
697:
681:beat frequency
662:
635:
551:The primitive
548:
545:
473:telegraph line
430:telegraph line
397:
390:
389:
369:
362:
361:
360:
359:
358:
346:
343:
331:high frequency
306:radio amateurs
156:
149:
148:
144:
137:
136:
135:
134:
133:
131:
128:
100:radiotelephony
15:
13:
10:
9:
6:
4:
3:
2:
3769:
3758:
3755:
3753:
3750:
3748:
3745:
3744:
3742:
3727:
3719:
3717:
3709:
3707:
3699:
3697:
3687:
3686:
3683:
3676:
3672:
3670:
3667:
3665:
3662:
3660:
3657:
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3648:
3645:
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3640:
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3637:
3635:
3632:
3631:
3629:
3625:
3619:
3616:
3614:
3611:
3609:
3606:
3604:
3601:
3599:
3596:
3594:
3591:
3589:
3586:
3584:
3581:
3579:
3576:
3574:
3571:
3570:
3568:
3566:
3562:
3556:
3553:
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3548:
3546:
3543:
3541:
3538:
3536:
3533:
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3528:
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3508:
3506:
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3501:
3498:
3496:
3493:
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3484:
3478:
3475:
3473:
3470:
3468:
3465:
3463:
3460:
3458:
3455:
3454:
3452:
3448:
3442:
3441:Code-division
3439:
3437:
3434:
3432:
3429:
3427:
3426:Time-division
3424:
3422:
3419:
3417:
3414:
3413:
3411:
3409:
3405:
3399:
3396:
3392:
3389:
3387:
3384:
3383:
3382:
3379:
3375:
3372:
3371:
3370:
3367:
3365:
3362:
3360:
3357:
3356:
3354:
3352:and switching
3350:
3346:
3338:
3335:
3334:
3333:
3330:
3326:
3323:
3322:
3321:
3318:
3316:
3313:
3311:
3308:
3304:
3303:optical fiber
3301:
3300:
3299:
3296:
3294:
3293:Coaxial cable
3291:
3290:
3288:
3286:
3280:
3274:
3271:
3269:
3266:
3264:
3261:
3259:
3256:
3254:
3251:
3249:
3246:
3244:
3241:
3239:
3236:
3234:
3231:
3229:
3226:
3224:
3221:
3219:
3216:
3214:
3211:
3209:
3208:Radia Perlman
3206:
3204:
3201:
3199:
3196:
3194:
3191:
3189:
3186:
3184:
3181:
3179:
3176:
3174:
3171:
3169:
3166:
3164:
3161:
3159:
3156:
3154:
3151:
3149:
3146:
3144:
3141:
3139:
3136:
3134:
3131:
3129:
3126:
3124:
3121:
3119:
3116:
3114:
3111:
3109:
3106:
3104:
3101:
3099:
3098:Lee de Forest
3096:
3094:
3093:Thomas Edison
3091:
3089:
3086:
3084:
3083:Donald Davies
3081:
3079:
3076:
3074:
3071:
3069:
3068:Claude Chappe
3066:
3064:
3061:
3059:
3056:
3054:
3051:
3049:
3046:
3044:
3041:
3039:
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3011:
3009:
3006:
3004:
3001:
2999:
2996:
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2989:
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2961:
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2946:
2945:
2941:
2939:
2936:
2933:
2930:
2928:
2925:
2923:
2920:
2918:
2915:
2913:
2912:Smoke signals
2910:
2906:
2903:
2901:
2898:
2896:
2893:
2892:
2891:
2890:Semiconductor
2888:
2884:
2881:
2880:
2879:
2876:
2874:
2871:
2869:
2866:
2864:
2861:
2859:
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2824:
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2819:
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2809:
2807:
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2799:
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2787:
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2782:
2779:
2777:
2774:
2770:
2767:
2765:
2762:
2760:
2757:
2755:
2752:
2751:
2750:
2749:Digital media
2747:
2743:
2740:
2738:
2735:
2733:
2730:
2728:
2725:
2724:
2723:
2720:
2718:
2715:
2713:
2710:
2708:
2705:
2703:
2700:
2698:
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2632:
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2618:
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2600:
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2557:
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2526:
2525:
2519:
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2513:
2512:
2506:
2505:
2500:
2499:
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2486:
2480:
2479:
2474:
2473:
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2454:
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2448:
2442:
2434:
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2427:
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2360:
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2328:
2327:
2321:
2320:
2315:
2314:
2308:
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2302:
2301:
2295:
2294:
2289:
2285:
2281:
2280:
2275:
2271:
2267:
2263:
2259:
2255:
2251:
2246:
2245:
2240:
2234:
2230:
2225:
2224:
2219:
2213:
2209:
2208:
2202:
2201:
2197:
2191:
2186:
2183:
2178:
2174:
2168:
2165:
2160:
2156:
2150:
2147:
2142:
2138:
2132:
2129:
2118:
2114:
2108:
2105:
2101:. 1922-08-10.
2100:
2093:
2087:
2084:
2072:
2068:
2062:
2059:
2048:
2044:
2038:
2035:
2031:
2027:
2024:
2019:
2016:
2005:
2001:
1994:
1991:
1980:
1976:
1970:
1967:
1962:
1956:
1952:
1948:
1941:
1935:
1933:
1929:
1924:
1920:
1916:
1910:
1907:
1895:
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1770:
1766:
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1754:
1749:
1746:
1734:
1728:
1725:
1721:
1717:
1713:
1707:
1704:
1692:
1690:9780313347436
1686:
1682:
1681:
1674:
1671:
1666:
1660:
1656:
1655:
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1644:
1639:
1633:
1629:
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1621:
1618:
1607:
1603:
1596:
1593:
1582:
1578:
1572:
1569:
1558:
1554:
1547:
1544:
1533:
1529:
1523:
1520:
1509:on 2021-04-17
1505:
1501:
1494:
1488:
1485:
1480:
1474:
1471:
1467:. 2020-10-23.
1463:
1457:
1455:
1453:
1449:
1437:
1433:
1427:
1424:
1413:
1406:
1403:
1400:
1395:
1392:
1389:
1384:
1381:
1368:
1361:
1358:
1353:
1351:9788184312829
1347:
1343:
1342:
1334:
1331:
1326:
1324:9780750626323
1320:
1316:
1315:
1307:
1304:
1299:
1297:9788122413397
1293:
1289:
1288:
1280:
1277:
1272:
1271:
1263:
1260:
1255:
1254:
1246:
1244:
1242:
1238:
1225:
1221:
1214:
1211:
1198:
1192:
1190:
1186:
1174:
1170:
1164:
1161:
1150:
1149:Atlas Obscura
1146:
1139:
1136:
1131:
1127:
1123:
1119:
1115:
1108:
1105:
1100:
1099:
1091:
1088:
1084:
1080:
1076:
1075:
1067:
1064:
1060:
1056:
1050:
1046:
1041:
1040:
1032:
1029:
1024:
1023:
1015:
1012:
1006:
1001:
997:
993:
992:
988:
983:
979:
978:Radioteletype
976:
974:
971:
969:
966:
963:
960:
959:
955:
949:
942:
937:
930:
925:
922:
915:
910:
907:
903:
899:
893:
888:
883:
881:
878:
873:
871:
867:
860:
858:
856:
851:
849:
845:
842:
838:
834:
833:radioteletype
830:
826:
822:
818:
813:
809:
801:
796:
789:
787:
785:
780:
775:
773:
769:
765:
761:
756:
753:
726:
722:
713:
704:
695:
686:
682:
660:
633:
624:
620:
616:
611:
609:
604:
602:
598:
594:
590:
586:
585:arc converter
581:
577:
573:
568:
566:
562:
558:
554:
546:
544:
542:
538:
534:
533:telegraph key
530:
529:audio signals
526:
522:
518:
514:
509:
506:
505:Telegraph Act
502:
498:
494:
489:
484:
482:
477:
474:
470:
465:
463:
459:
455:
451:
447:
446:telegraph key
443:
439:
435:
431:
427:
418:
408:
405:
401:
394:
385:
381:
378:and receiver
377:
373:
366:
356:
352:
344:
342:
340:
336:
332:
327:
323:
319:
318:amateur radio
315:
311:
307:
302:
300:
296:
292:
291:radio beacons
289:
285:
281:
277:
276:amateur radio
273:
269:
263:
261:
257:
253:
249:
245:
241:
240:telegraph key
237:
232:
230:
226:
225:radioteletype
222:
218:
214:
210:
207:
203:
199:
195:
191:
187:
183:
179:
175:
171:
170:on-off keying
167:
153:
141:
129:
127:
125:
124:amateur radio
121:
117:
111:
109:
105:
101:
97:
93:
89:
85:
81:
76:
74:
70:
66:
65:telegraph key
62:
57:
53:
49:
45:
41:
37:
30:
26:
21:
3408:Multiplexing
3283:Transmission
3248:Nikola Tesla
3238:Henry Sutton
3193:Samuel Morse
3123:Robert Hooke
3088:Amos Dolbear
3023:John Bardeen
2942:
2922:Telautograph
2826:Mobile phone
2781:Edholm's law
2764:social media
2697:Broadcasting
2637:
2629:
2615:
2592:
2576:
2564:
2549:
2536:
2523:
2510:
2497:
2484:
2471:
2458:
2431:
2417:
2404:
2391:
2379:
2364:
2351:
2338:
2325:
2312:
2299:
2287:
2257:
2253:
2228:
2206:
2185:
2176:
2167:
2158:
2149:
2140:
2131:
2120:. Retrieved
2116:
2107:
2098:
2086:
2075:. Retrieved
2073:. 2024-05-15
2070:
2061:
2050:. Retrieved
2046:
2037:
2018:
2007:. Retrieved
2003:
1993:
1982:. Retrieved
1978:
1969:
1950:
1946:
1923:the original
1909:
1898:. Retrieved
1896:. 2015-12-31
1893:
1884:
1875:
1865:
1854:. Retrieved
1850:
1826:. Retrieved
1822:
1790:
1783:
1772:. Retrieved
1768:
1759:
1748:
1737:. Retrieved
1727:
1711:
1706:
1694:. Retrieved
1679:
1673:
1653:
1646:
1626:
1620:
1609:. Retrieved
1605:
1595:
1584:. Retrieved
1580:
1571:
1560:. Retrieved
1556:
1546:
1535:. Retrieved
1532:www.elon.edu
1531:
1522:
1511:. Retrieved
1504:the original
1499:
1487:
1473:
1440:. Retrieved
1438:. 2021-04-01
1436:www.arrl.org
1435:
1426:
1415:. Retrieved
1405:
1394:
1383:
1371:. Retrieved
1360:
1340:
1333:
1313:
1306:
1286:
1279:
1269:
1262:
1252:
1228:. Retrieved
1223:
1213:
1201:. Retrieved
1177:. Retrieved
1175:. 2024-04-12
1172:
1163:
1152:. Retrieved
1148:
1138:
1113:
1107:
1097:
1090:
1082:
1073:
1066:
1058:
1038:
1031:
1021:
1014:
905:
901:
874:
864:
852:
821:broadcasting
805:
776:
757:
612:
608:carrier wave
605:
569:
550:
523:, primitive
512:
510:
485:
478:
466:
423:
406:
379:
375:
303:
264:
256:teleprinters
244:carrier wave
233:
229:World War II
209:carrier wave
194:damped waves
163:
112:
80:transmitters
77:
55:
39:
35:
34:
25:Signal Corps
3608:NPL network
3320:Radio waves
3258:Alfred Vail
3168:Hedy Lamarr
3153:Dawon Kahng
3113:Elisha Gray
3073:Yogen Dalal
2998:Nasir Ahmed
2932:Teleprinter
2796:Heliographs
2435:. New York.
2260:(1): 1–20.
1373:19 November
1203:19 November
921:World War I
779:World War I
557:damped wave
481:radio waves
299:identifiers
202:vacuum tube
92:World War I
69:transmitter
44:radio waves
3752:Telegraphy
3741:Categories
3654:Antarctica
3613:Toasternet
3535:Television
3018:Paul Baran
2950:Television
2934:(teletype)
2927:Telegraphy
2905:transistor
2883:Phryctoria
2853:Photophone
2831:Smartphone
2821:Mass media
2238:0471018163
2122:2024-05-23
2077:2024-05-23
2052:2024-05-21
2009:2024-05-21
1984:2024-05-23
1900:2024-05-23
1856:2024-05-21
1828:2024-05-21
1774:2024-05-21
1739:2012-04-15
1611:2024-05-22
1586:2024-05-22
1562:2024-05-22
1537:2024-05-22
1513:2021-05-06
1442:2021-05-08
1417:2021-05-08
1179:2024-05-17
1154:2024-05-17
1054:0877798095
861:Regulation
848:short wave
760:oscillator
685:heterodyne
517:Morse code
450:Morse code
400:Morse code
386:, May 1897
248:Morse code
206:sinusoidal
186:modulation
130:Principles
116:world wars
61:Morse code
29:New Guinea
23:A US Army
3638:Americas
3627:Locations
3598:Internet2
3359:Bandwidth
3063:Vint Cerf
2960:streaming
2938:Telephone
2878:Semaphore
2769:streaming
2441:cite book
2419:Operation
2274:0021-938X
2210:. Wiley.
1845:ID, FCC.
1720:655205099
1007:Citations
825:telegrams
723:−
565:bandwidth
537:earphones
444:called a
384:Flat Holm
339:call sign
238:called a
198:bandwidth
84:receivers
3706:Category
3593:Internet
3583:CYCLADES
3500:Ethernet
3450:Concepts
3374:terminal
3325:wireless
3148:Bob Kahn
2991:Pioneers
2816:Internet
2707:Cable TV
2026:Archived
1851:FCCID.io
1230:16 March
956:See also
790:Industry
615:detector
380:(bottom)
376:(center)
252:receiver
108:telegram
73:receiver
3726:Commons
3716:Outline
3669:Oceania
3588:FidoNet
3573:ARPANET
3386:circuit
2955:digital
2684:History
2143:. 1968.
1696:July 8,
1130:6928472
989:General
902:(right)
884:Gallery
875:The US
547:Methods
454:battery
372:Marconi
345:History
211:called
180:, is a
3664:Europe
3634:Africa
3618:Usenet
3578:BITNET
3515:Mobile
3391:packet
2900:MOSFET
2895:device
2692:Beacon
2640:(1919)
2633:(1919)
2619:{1904}
2272:
2235:
2214:
1957:
1798:
1718:
1687:
1661:
1634:
1348:
1321:
1294:
1128:
1051:
906:(left)
462:ground
442:switch
407:(left)
236:switch
52:cables
50:using
3647:South
3642:North
3603:JANET
3540:Telex
3530:Radio
3369:Nodes
3364:Links
3285:media
2863:Radio
2848:Pager
2776:Drums
2742:video
2737:image
2727:audio
2095:(PDF)
1943:(PDF)
1507:(PDF)
1496:(PDF)
1465:(PDF)
1126:S2CID
855:GMDSS
841:CCITT
837:telex
561:hertz
541:radio
272:GMDSS
104:audio
98:(AM)
3659:Asia
3545:UUCP
3505:ISDN
2447:link
2270:ISSN
2233:ISBN
2212:ISBN
1955:ISBN
1796:ISBN
1716:OCLC
1698:2011
1685:ISBN
1659:ISBN
1632:ISBN
1375:2021
1346:ISBN
1319:ISBN
1292:ISBN
1232:2018
1205:2021
1049:ISBN
1045:1437
844:R.44
827:and
700:BEAT
599:and
583:the
353:and
335:CEPT
286:and
82:and
3550:WAN
3520:NGN
3510:LAN
2791:Fax
2732:DCT
2262:doi
1118:doi
1079:333
998:",
762:by
731:BFO
638:BFO
382:on
322:FT8
288:NDB
280:KSM
176:as
38:or
3743::
2613:,
2595::
2563:.
2443:}}
2439:{{
2378:.
2286:.
2268:.
2258:15
2256:.
2252:.
2175:.
2157:.
2139:.
2115:.
2097:.
2069:.
2045:.
2002:.
1977:.
1951:22
1949:.
1945:.
1931:^
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