73-409: The Q-code is a standardised collection of three-letter codes that each start with the letter "Q". It is an operating signal initially developed for commercial radiotelegraph communication and later adopted by other radio services, especially amateur radio . To distinguish the use of a Q-code transmitted as a question from the same Q-code transmitted as a statement, operators either prefixed it with
146-470: A dah is three times the duration of a dit (although some telegraphers deliberately exaggerate the length of a dah for clearer signalling). Each dit or dah within an encoded character is followed by a period of signal absence, called a space , equal to the dit duration. The letters of a word are separated by a space of duration equal to three dits , and words are separated by a space equal to seven dits . Morse code can be memorized and sent in
219-722: A 360-degree turn immediately (turning to the ____). or Use your full call sign until further notice. or Work on a trailing aerial. or What is the D-Value at ____ ( place or position ) (at ____ hours) for the ____ millibar level? or The D-Value at ____ ( place or position ) at ____ hours for the ____ millibar level is ( D-Value figures and units ) ____ ( specify plus or minus ). or You are cleared subject to maintaining own separation and visual meteorological conditions. or IFR flight cancelled at ____ ( time ). or Have you reached your parking area? or I have reached my parking area. or Have you left
292-462: A code became voiced as di . For example, the letter L ( ▄ ▄▄▄ ▄ ▄ ) is voiced as di dah di dit . Morse code was sometimes facetiously known as "iddy-umpty", a dit lampooned as "iddy" and a dah as "umpty", leading to the word " umpteen ". The Morse code, as specified in the current international standard, International Morse Code Recommendation , ITU-R M.1677-1,
365-578: A code proficiency certification program that starts at 10 WPM . The relatively limited speed at which Morse code can be sent led to the development of an extensive number of abbreviations to speed communication. These include prosigns, Q codes , and a set of Morse code abbreviations for typical message components. For example, CQ is broadcast to be interpreted as "seek you" (I'd like to converse with anyone who can hear my signal). The abbreviations OM (old man), YL (young lady), and XYL ("ex-young lady" – wife) are common. YL or OM
438-416: A code system developed by Steinheil. A new codepoint was added for J since Gerke did not distinguish between I and J . Changes were also made to X , Y , and Z . This left only four codepoints identical to the original Morse code, namely E , H , K and N , and the latter two had their dahs extended to full length. The original American code being compared dates to 1838;
511-550: A codebook to look up each word according to the number which had been sent. However, the code was soon expanded by Alfred Vail in 1840 to include letters and special characters, so it could be used more generally. Vail estimated the frequency of use of letters in the English language by counting the movable type he found in the type-cases of a local newspaper in Morristown, New Jersey . The shorter marks were called "dots" and
584-407: A form perceptible to the human senses, e.g. via sound waves or visible light, such that it can be directly interpreted by persons trained in the skill. Morse code is usually transmitted by on-off keying of an information-carrying medium such as electric current, radio waves, visible light, or sound waves. The current or wave is present during the time period of the dit or dah and absent during
657-408: A method, an early forerunner to the modern International Morse code. The Morse system for telegraphy , which was first used in about 1844, was designed to make indentations on a paper tape when electric currents were received. Morse's original telegraph receiver used a mechanical clockwork to move a paper tape. When an electrical current was received, an electromagnet engaged an armature that pushed
730-560: A slow data rate) than voice communication (roughly 2,400~2,800 Hz used by SSB voice ). Morse code is usually received as a high-pitched audio tone, so transmissions are easier to copy than voice through the noise on congested frequencies, and it can be used in very high noise / low signal environments. The fact that the transmitted power is concentrated into a very limited bandwidth makes it possible to use narrow receiver filters, which suppress or eliminate interference on nearby frequencies. The narrow signal bandwidth also takes advantage of
803-721: A storm") would be voice or computerised transmissions. But several remain part of the standard ICAO radiotelephony phraseology in aviation. These are also part of ACP131 , which lists all ITU-R Q-codes, without grouping them by aeronautical/marine/general use. or I am arranging my flight in order to arrive over ____ ( place ) at ____ hours. or Arrange your flight so as to reach flight level / altitude ____ at ____ ( hours or place ). or Has aircraft ____ landed at ____ ( place )? or (You may) land at ____ ( place ). or Aircraft ____ landed at ____ ( place ). or Am I near area ____ ( identification of area )? or Jettison fuel in ____ ( area ). or Maintain
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#1732773243839876-487: A straight key was achieved in 1942 by Harry Turner ( W9YZE ) (d. 1992) who reached 35 WPM in a demonstration at a U.S. Army base. To accurately compare code copying speed records of different eras it is useful to keep in mind that different standard words (50 dit durations versus 60 dit durations) and different interword gaps (5 dit durations versus 7 dit durations) may have been used when determining such speed records. For example, speeds run with
949-404: A stylus onto the moving paper tape, making an indentation on the tape. When the current was interrupted, a spring retracted the stylus and that portion of the moving tape remained unmarked. Morse code was developed so that operators could translate the indentations marked on the paper tape into text messages. In his earliest design for a code, Morse had planned to transmit only numerals, and to use
1022-517: A telegraph that printed the letters from a wheel of typefaces struck by a hammer. The American artist Samuel Morse , the American physicist Joseph Henry , and mechanical engineer Alfred Vail developed an electrical telegraph system. The simple "on or off" nature of its signals made it desirable to find a method of transmitting natural language using only electrical pulses and the silence between them. Around 1837, Morse therefore developed such
1095-457: A vertical distance of ____ ( figures and units ) above clouds, smoke, haze or fog levels. or Maintain a vertical distance of ____ ( figures and units ) below cloud. or Report reaching flight level/altitude ____ [ or ____ ( area or place )]. or Report leaving flight level/altitude ____ [ or ____ ( area or place )]. or I am changing my flight level/altitude from ____ to ____. or No delay expected. or I am making
1168-427: Is a telecommunications method which encodes text characters as standardized sequences of two different signal durations, called dots and dashes , or dits and dahs . Morse code is named after Samuel Morse , one of the early developers of the system adopted for electrical telegraphy . International Morse code encodes the 26 basic Latin letters A to Z , one accented Latin letter ( É ),
1241-442: Is abc, what is yours?" Used in their formal question / answer sense, the meaning of a Q-code varies depending on whether the individual Q-code is sent as a question or an answer. For example, the message "QRP?" means "Shall I decrease transmitter power?", and a reply of "QRP" means "Yes, decrease your transmitter power", whereas an unprompted statement "QRP" means "Please decrease your transmitter power". This structured use of Q-codes
1314-758: Is allocated to the International Telecommunication Union . QVA–QZZ are not allocated. Many codes have no immediate applicability outside one individual service, such as maritime operation (many QO or QU series codes) or radioteletype operation (the QJ series). Many military and other organisations that use Morse code have adopted additional codes, including the Z code used by most European and NATO countries. The Z code adds commands and questions adapted for military radio transmissions, for example, "ZBW 2", which means "change to backup frequency number 2", and "ZNB abc", which means "my checksum
1387-471: Is called Morse code today is actually somewhat different from what was originally developed by Vail and Morse. The Modern International Morse code, or continental code , was created by Friedrich Clemens Gerke in 1848 and initially used for telegraphy between Hamburg and Cuxhaven in Germany. Gerke changed nearly half of the alphabet and all of the numerals , providing the foundation for the modern form of
1460-541: Is fairly rare and now mainly limited to amateur radio and military Morse code (CW) traffic networks. First defined in ICAO publication "Doc 6100-COM/504/1" and in "ICAO Procedures for Air Navigation Services, Abbreviations and Codes (PANS-ABC)" [Doc8400-4] (4th edition 1989), the majority of the Q-codes have fallen out of common use; for example today reports such as QAU ("I am about to jettison fuel") and QAZ ("I am flying in
1533-476: Is most popular among amateur radio operators, in the mode commonly referred to as " continuous wave " or "CW". Other, faster keying methods are available in radio telegraphy, such as frequency-shift keying (FSK). The original amateur radio operators used Morse code exclusively since voice-capable radio transmitters did not become commonly available until around 1920. Until 2003, the International Telecommunication Union mandated Morse code proficiency as part of
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#17327732438391606-434: Is not to be used. In the aviation service, Morse is typically sent at a very slow speed of about 5 words per minute. In the U.S., pilots do not actually have to know Morse to identify the transmitter because the dot/dash sequence is written out next to the transmitter's symbol on aeronautical charts. Some modern navigation receivers automatically translate the code into displayed letters. International Morse code today
1679-530: Is supposed to have higher readability for both robot and human decoders. Some programs like WinMorse have implemented the standard. Radio navigation aids such as VORs and NDBs for aeronautical use broadcast identifying information in the form of Morse Code, though many VOR stations now also provide voice identification. Warships, including those of the U.S. Navy , have long used signal lamps to exchange messages in Morse code. Modern use continues, in part, as
1752-416: Is taught "like a language", with each code perceived as a whole "word" instead of a sequence of separate dots and dashes, such as might be shown on a page. With the advent of tones produced by radiotelegraph receivers, the operators began to vocalize a dot as dit , and a dash as dah , to reflect the sounds of Morse code they heard. To conform to normal sending speed, dits which are not the last element of
1825-413: Is used by an operator when referring to the other operator (regardless of their actual age), and XYL or OM (rather than the expected XYM ) is used by an operator when referring to his or her spouse. QTH is "transmitting location" (spoken "my Q.T.H." is "my location"). The use of abbreviations for common terms permits conversation even when the operators speak different languages. Although
1898-645: Is used by the Miami-Dade County, Florida local government for law enforcement and fire rescue communications, one of the few instances where Q-codes are used in ground voice communication. The QAA–QNZ code range includes phrases applicable primarily to the aeronautical service, as defined by the International Civil Aviation Organization . The QOA–QQZ code range is reserved for the maritime service. The QRA–QUZ code range includes phrases applicable to all services and
1971-694: The CODEX standard word and the PARIS standard may differ by up to 20%. Today among amateur operators there are several organizations that recognize high-speed code ability, one group consisting of those who can copy Morse at 60 WPM . Also, Certificates of Code Proficiency are issued by several amateur radio societies, including the American Radio Relay League . Their basic award starts at 10 WPM with endorsements as high as 40 WPM , and are available to anyone who can copy
2044-777: The Spirit of St. Louis were off the ground, Lindbergh was truly incommunicado and alone. Morse code in aviation began regular use in the mid-1920s. By 1928, when the first airplane flight was made by the Southern Cross from California to Australia, one of its four crewmen was a radio operator who communicated with ground stations via radio telegraph . Beginning in the 1930s, both civilian and military pilots were required to be able to use Morse code, both for use with early communications systems and for identification of navigational beacons that transmitted continuous two- or three-letter identifiers in Morse code. Aeronautical charts show
2117-708: The ARRL and used in Amateur radio R and S brevity codes: published by the British Post Office in 1908 for coastal wireless stations and ships, superseded in 1912 by Q codes X code: used by European military services in wireless telegraphy Z code : used in early radiotelegraph communication See also [ edit ] Brevity code SINPO code - code used to describe the quality of radio transmissions, especially in reception reports written by shortwave listeners R-S-T system - information about
2190-455: The Arabic numerals , and a small set of punctuation and procedural signals ( prosigns ). There is no distinction between upper and lower case letters. Each Morse code symbol is formed by a sequence of dits and dahs . The dit duration can vary for signal clarity and operator skill, but for any one message, once established it is the basic unit of time measurement in Morse code. The duration of
2263-770: The Double Plate Sounder System. William Cooke and Charles Wheatstone in Britain developed an electrical telegraph that used electromagnets in its receivers. They obtained an English patent in June ;1837 and demonstrated it on the London and Birmingham Railway, making it the first commercial telegraph. Carl Friedrich Gauss and Wilhelm Eduard Weber (1833) as well as Carl August von Steinheil (1837) used codes with varying word lengths for their telegraph systems. In 1841, Cooke and Wheatstone built
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2336-700: The Soviet Union , and in North Africa ; by the British Army in North Africa , Italy , and the Netherlands ; and by the U.S. Army in France and Belgium (in 1944), and in southern Germany in 1945. Radiotelegraphy using Morse code was vital during World War II , especially in carrying messages between the warships and the naval bases of the belligerents. Long-range ship-to-ship communication
2409-725: The prosign SK ("end of contact"). As of 2015 , the United States Air Force still trains ten people a year in Morse. The United States Coast Guard has ceased all use of Morse code on the radio, and no longer monitors any radio frequencies for Morse code transmissions, including the international medium frequency (MF) distress frequency of 500 kHz . However, the Federal Communications Commission still grants commercial radiotelegraph operator licenses to applicants who pass its code and written tests. Licensees have reactivated
2482-420: The spark gap system of transmission was dangerous and difficult to use, there had been some early attempts: In 1910, the U.S. Navy experimented with sending Morse from an airplane. However the first regular aviation radiotelegraphy was on airships , which had space to accommodate the large, heavy radio equipment then in use. The same year, 1910, a radio on the airship America was instrumental in coordinating
2555-696: The 1920s spark-gap transmitters were gradually being banned from land stations, making that meaning obsolete. By the 1970s, the Post Office Handbook for Radio Operators listed over a hundred Q-codes, covering a wide range of subjects including radio procedures, meteorology, radio direction finding, and search and rescue. Some Q-codes are also used in aviation , in particular QNE, QNH and QFE, referring to certain altimeter settings . These codes are used in radiotelephone conversations with air traffic control as unambiguous shorthand, where safety and efficiency are of vital importance. A subset of Q-codes
2628-601: The British government as a "List of abbreviations ... prepared for the use of British ships and coast stations licensed by the Postmaster General ". The Q-codes facilitated communication between maritime radio operators speaking different languages, so they were soon adopted internationally. A total of forty-five Q-codes appeared in the "List of Abbreviations to be used in Radio Communications", which
2701-701: The FCC eliminated the Morse code proficiency requirements from all amateur radio licenses. While voice and data transmissions are limited to specific amateur radio bands under U.S. rules, Morse code is permitted on all amateur bands: LF , MF low , MF high , HF , VHF , and UHF . In some countries, certain portions of the amateur radio bands are reserved for transmission of Morse code signals only. Because Morse code transmissions employ an on-off keyed radio signal, it requires less complex equipment than other radio transmission modes . Morse code also uses less bandwidth (typically only 100–150 Hz wide, although only for
2774-532: The International code used everywhere else, including all ships at sea and sailing in North American waters. Morse's version became known as American Morse code or railroad code , and is now almost never used, with the possible exception of historical re-enactments. In aviation , pilots use radio navigation aids. To allow pilots to ensure that the stations they intend to use are serviceable,
2847-630: The Second and First are renewed and become this lifetime license. For new applicants, it requires passing a written examination on electronic theory and radiotelegraphy practices, as well as 16 WPM code-group and 20 WPM text tests. However, the code exams are currently waived for holders of Amateur Extra Class licenses who obtained their operating privileges under the old 20 WPM test requirement. Morse codes of one version or another have been in use for more than 160 years — longer than any other electrical message encoding system. What
2920-552: The United States from the Federal Communications Commission . Demonstration of this ability was still required for the privilege to use the shortwave bands . Until 2000, proficiency at the 20 WPM level was required to receive the highest level of amateur license (Amateur Extra Class); effective April 15, 2000, in the FCC reduced the Extra Class requirement to 5 WPM . Finally, effective on February 23, 2007,
2993-544: The amateur radio licensing procedure worldwide. However, the World Radiocommunication Conference of 2003 made the Morse code requirement for amateur radio licensing optional. Many countries subsequently removed the Morse requirement from their license requirements. Until 1991, a demonstration of the ability to send and receive Morse code at a minimum of five words per minute ( WPM ) was required to receive an amateur radio license for use in
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3066-543: The character that it represents in text of the English language. Thus the most common letter in English, the letter E , has the shortest code – a single dit . Because the Morse code elements are specified by proportion rather than specific time durations, the code is usually transmitted at the highest rate that the receiver is capable of decoding. Morse code transmission rate ( speed ) is specified in groups per minute , commonly referred to as words per minute . Early in
3139-565: The code. After some minor changes to the letters and a complete revision of the numerals, International Morse Code was standardized by the International Telegraphy Congress in 1865 in Paris, and later became the standard adopted by the International Telecommunication Union (ITU). Morse and Vail's final code specification, however, was only really used only for land-line telegraphy in the United States and Canada, with
3212-414: The facility may instead transmit the signal TEST ( ▄▄▄ ▄ ▄ ▄ ▄ ▄▄▄ ), or the identification may be removed, which tells pilots and navigators that the station is unreliable. In Canada, the identification is removed entirely to signify the navigation aid
3285-655: The floodlights. or Work on a fixed aerial. or What track are you making good? or I am making good a track from ____ ( place ) on ____ degrees ____ ( true or magnetic ). Operating signals Signals for management of telegraph circuits Operating signals are a type of brevity code used in operational communication among radio and telegraph operators. For example: Prosigns for Morse code 92 Code : telegraph brevity codes Q code : initially developed for commercial radiotelegraph communication and adopted by other radio services QN Signals : published by
3358-612: The frequently used vowel O . Gerke changed many of the codepoints, in the process doing away with the different length dashes and different inter-element spaces of American Morse , leaving only two coding elements, the dot and the dash. Codes for German umlauted vowels and CH were introduced. Gerke's code was adopted in Germany and Austria in 1851. This finally led to the International Morse code in 1865. The International Morse code adopted most of Gerke's codepoints. The codes for O and P were taken from
3431-552: The holder to be chief operator on board a passenger ship. However, since 1999 the use of satellite and very high-frequency maritime communications systems ( GMDSS ) has made them obsolete. (By that point meeting experience requirement for the First was very difficult.) Currently, only one class of license, the Radiotelegraph Operator License, is issued. This is granted either when the tests are passed or as
3504-538: The identifier of each navigational aid next to its location on the map. In addition, rapidly moving field armies could not have fought effectively without radiotelegraphy; they moved more quickly than their communications services could put up new telegraph and telephone lines. This was seen especially in the blitzkrieg offensives of the Nazi German Wehrmacht in Poland , Belgium , France (in 1940),
3577-571: The introduction of voice transmissions. To avoid confusion, transmitter call signs are restricted; countries can be issued unused Q-Codes as their ITU prefix e.g. Qatar is QAT . Codes in the range QAA–QNZ are reserved for aeronautical use; QOA–QQZ for maritime use and QRA–QUZ for all services. "Q" has no official meaning, but it is sometimes assigned a word with mnemonic value, such as "question" or "query", for example in QFE: "query field elevation". The original Q-codes were created, circa 1909, by
3650-506: The invention of the electromagnet by William Sturgeon in 1824, there were developments in electromagnetic telegraphy in Europe and America. Pulses of electric current were sent along wires to control an electromagnet in the receiving instrument. Many of the earliest telegraph systems used a single-needle system which gave a very simple and robust instrument. However, it was slow, as the receiving operator had to alternate between looking at
3723-409: The later American code shown in the table was developed in 1844. In the 1890s, Morse code began to be used extensively for early radio communication before it was possible to transmit voice. In the late 19th and early 20th centuries, most high-speed international communication used Morse code on telegraph lines, undersea cables, and radio circuits. Although previous transmitters were bulky and
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#17327732438393796-443: The longer ones "dashes", and the letters most commonly used were assigned the shortest sequences of dots and dashes. This code, first used in 1844, was what later became known as Morse landline code , American Morse code , or Railroad Morse , until the end of railroad telegraphy in the U.S. in the 1970s. In the original Morse telegraph system, the receiver's armature made a clicking noise as it moved in and out of position to mark
3869-446: The military network question marker " INT " ( ▄ ▄ ▄▄▄ ▄ ▄▄▄ ) or suffixed it with the standard Morse question mark UD ( ▄ ▄ ▄▄▄ ▄▄▄ ▄ ▄ ). Although Q-codes were created when radio used Morse code exclusively, they continued to be employed after
3942-505: The natural aural selectivity of the human brain, further enhancing weak signal readability. This efficiency makes CW extremely useful for DX (long distance) transmissions , as well as for low-power transmissions (commonly called " QRP operation ", from the Q-code for "reduce power"). There are several amateur clubs that require solid high speed copy, the highest of these has a standard of 60 WPM . The American Radio Relay League offers
4015-406: The needle and writing down the message. In Morse code, a deflection of the needle to the left corresponded to a dit and a deflection to the right to a dah . The needle clicked each time it moved to the right or left. By making the two clicks sound different (by installing one ivory and one metal stop), transmissions on the single needle device became audible as well as visible, which led in turn to
4088-422: The nineteenth century, European experimenters made progress with electrical signaling systems, using a variety of techniques including static electricity and electricity from Voltaic piles producing electrochemical and electromagnetic changes. These experimental designs were precursors to practical telegraphic applications. Following the discovery of electromagnetism by Hans Christian Ørsted in 1820 and
4161-494: The old California coastal Morse station KPH and regularly transmit from the site under either this call sign or as KSM. Similarly, a few U.S. museum ship stations are operated by Morse enthusiasts. Morse code speed is measured in words per minute ( WPM ) or characters per minute ( CPM ). Characters have differing lengths because they contain differing numbers of dits and dahs . Consequently, words also have different lengths in terms of dot duration, even when they contain
4234-472: The others 16 WPM code group test (five letter blocks sent as simulation of receiving encrypted text) and 20 WPM code text (plain language) test. It was also necessary to pass written tests on operating practice and electronics theory. A unique additional demand for the First Class was a requirement of a year of experience for operators of shipboard and coast stations using Morse. This allowed
4307-408: The paper tape. Early telegraph operators soon learned that they could translate the clicks directly into dots and dashes, and write these down by hand, thus making the paper tape unnecessary. When Morse code was adapted to radio communication , the dots and dashes were sent as short and long tone pulses. Later telegraphy training found that people become more proficient at receiving Morse code when it
4380-420: The parking area? or I have left the parking area. or Have you moved to the holding position for runway number ____ ? or I have moved to the holding position for runway number ____. or Have you assumed position for take-off? or I am assuming take-off position for runway number ____ and am holding. or Have you cleared the runway ( or landing area)? or I have cleared
4453-1294: The quality of a radio signal being received. Used by amateur radio operators, shortwave listeners. Morse code abbreviations Telegraphese External links [ edit ] Nonsecret Code: An Overview of Early Telegraph Codes References [ edit ] ^ Anderson, Scott (31 July 2002). "Pre-1912 Brevity Codes" . v t e International Morse code Transmission methods Electrical telegraph On–off keying Continuous wave Modulated continuous wave Heliograph Signal lamp Notable signals SOS CQD Morse code mnemonics Prosigns for Morse code Morse code abbreviations Q code Z code Other writing systems in Morse code American Morse code Greek alphabet Cyrillic script Russian Hebrew script Arabic script Wabun code Chinese telegraph code Retrieved from " https://en.wikipedia.org/w/index.php?title=Operating_signals&oldid=1156245822 " Category : Operating signals Hidden categories: Articles with short description Short description matches Wikidata Use dmy dates from May 2023 Morse code Morse code
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#17327732438394526-527: The rescue of its crew. During World War I , Zeppelin airships equipped with radio were used for bombing and naval scouting, and ground-based radio direction finders were used for airship navigation. Allied airships and military aircraft also made some use of radiotelegraphy. However, there was little aeronautical radio in general use during World War I , and in the 1920s, there was no radio system used by such important flights as that of Charles Lindbergh from New York to Paris in 1927. Once he and
4599-400: The runway ( or landing area). or Please light the aerodrome lights. 1. Maintain ( or fly at) flight level / altitude ____. 2. I am maintaining flight level / altitude ____ 3. I intend cruising at flight level/altitude ____. or Please light the approach and runway lights. or Please have the ____ radio facility at ____ ( place ) put in operation. or Please switch on
4672-538: The same number of characters. For this reason, some standard word is adopted for measuring operators' transmission speeds: Two such standard words in common use are PARIS and CODEX . Operators skilled in Morse code can often understand ("copy") code in their heads at rates in excess of 40 WPM . In addition to knowing, understanding, and being able to copy the standard written alpha-numeric and punctuation characters or symbols at high speeds, skilled high-speed operators must also be fully knowledgeable of all of
4745-688: The special unwritten Morse code symbols for the standard Prosigns for Morse code and the meanings of these special procedural signals in standard Morse code communications protocol . International contests in code copying are still occasionally held. In July 1939 at a contest in Asheville, North Carolina in the United States, Theodore Roosevelt McElroy ( W1JYN ) set a still-standing record for Morse copying, 75.2 WPM . Pierpont (2004) also notes that some operators may have passed 100 WPM . By this time, they are "hearing" phrases and sentences rather than words. The fastest speed ever sent by
4818-546: The stations transmit a set of identification letters (usually a two-to-five-letter version of the station name) in Morse code. Station identification letters are shown on air navigation charts. For example, the VOR-DME based at Vilo Acuña Airport in Cayo Largo del Sur, Cuba is identified by " UCL ", and Morse code UCL is repeatedly transmitted on its radio frequency. In some countries, during periods of maintenance,
4891-462: The time between dits and dahs . Since many natural languages use more than the 26 letters of the Latin alphabet , Morse alphabets have been developed for those languages, largely by transliteration of existing codes. To increase the efficiency of transmission, Morse code was originally designed so that the duration of each symbol is approximately inverse to the frequency of occurrence of
4964-469: The traditional telegraph key (straight key) is still used by some amateurs, the use of mechanical semi-automatic keyers (informally called "bugs"), and of fully automatic electronic keyers (called "single paddle" and either "double-paddle" or "iambic" keys) is prevalent today. Software is also frequently employed to produce and decode Morse code radio signals. The ARRL has a readability standard for robot encoders called ARRL Farnsworth spacing that
5037-669: The transmitted text. Members of the Boy Scouts of America may put a Morse interpreter's strip on their uniforms if they meet the standards for translating code at 5 WPM . Through May 2013, the First, Second, and Third Class (commercial) Radiotelegraph Licenses using code tests based upon the CODEX standard word were still being issued in the United States by the Federal Communications Commission. The First Class license required 20 WPM code group and 25 WPM text code proficiency,
5110-435: Was by radio telegraphy, using encrypted messages because the voice radio systems on ships then were quite limited in both their range and their security. Radiotelegraphy was also extensively used by warplanes , especially by long-range patrol planes that were sent out by navies to scout for enemy warships, cargo ships, and troop ships. Morse code was used as an international standard for maritime distress until 1999 when it
5183-408: 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 ▄▄▄ ▄▄▄ ▄▄▄ ) for
5256-662: Was included in the Service Regulations affixed to the Second International Radiotelegraph Convention in London (The Convention was signed on July 5, 1912, and became effective July 1, 1913.) The following table reviews a sample of the all-services Q-codes adopted by the 1912 convention: Over the years the original Q-codes were modified to reflect changes in radio practice. For example, QSW / QSX originally stood for, "Shall I increase / decrease my spark frequency?", but in
5329-549: Was replaced by the Global Maritime Distress and Safety System . When the French Navy ceased using Morse code on January 31, 1997, the final message transmitted was "Calling all. This is our last call before our eternal silence." In the United States the final commercial Morse code transmission was on July 12, 1999, signing off with Samuel Morse's original 1844 message, WHAT HATH GOD WROUGHT , and
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