Morse Code "CW"
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment. The International Morse Code encodes the ISO basic Latin alphabet, some extra Latin letters, the Arabic numerals and a small set of punctuation and procedural signals as standardized sequences of short and long signals called "dots" and "dashes" respectively, or "dits" and "dahs". Because many non-English natural languages use more than the 26 Roman letters, extensions to the Morse alphabet exist for those languages.
Each character (letter or numeral) is represented by a unique sequence of dots and dashes. The duration of a dash is three times the duration of a dot. Each dot or dash is followed by a short silence, equal to the dot duration. The letters of a word are separated by a space equal to three dots (one dash), and two words are separated by a space equal to seven dots. The dot duration is the basic unit of time measurement in code transmission.
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 dots and dashes. Consequently words also have different lengths in terms of dot duration, even when they contain the same number of characters. For this reason, a standard word is helpful to measure operator transmission speed. "PARIS" and "CODEX" are two such standard words.
One important feature of Morse code is coding efficiency. The length of each character in Morse is approximately inversely proportional to its frequency of occurrence in English. Thus, the most common letter in English, the letter "E," has the shortest code, a single dot.
A related but different code was originally created for 'Samuel F. B. Morse electric telegraph by Alfred Vail in the early 1840s. This code was the forerunner on which modern International Morse code is based. In the 1890s it began to be extensively used for early radio communication before it was possible to transmit voice. In the late nineteenth and early twentieth century, most high-speed international communication used Morse code on telegraph lines, undersea cables and radio circuits.
Morse code is most popular among amateur radio operators although it is no longer required for licensing in most countries, including the US. Pilots and air traffic controllers are usually familiar with Morse code and require a basic understanding. Aeronautical navigational aids, such as VORs and NDBs, constantly identify in Morse code. An advantage of Morse code for transmitting over radio waves is that it is able to be received over poor signal conditions that would make voice communications impossible.
Because it can be read by humans without a decoding device, Morse is sometimes a useful alternative to synthesized speech for sending automated digital data to skilled listeners on voice channels. Many amateur radio repeaters, for example, identify with Morse even though they are used for voice communications.
For emergency signals, Morse code can be sent by way of improvised sources that can be easily "keyed" on and off, making it one of the simplest and most versatile methods of telecommunication. The most common distress signal is SOS or three dots, three dashes and three dots, internationally recognized.
Letters, numbers, punctuation
|· —||· — — —||· · ·||· — — — —||Period||· — · — · —||Colon||— — — · · ·|
|— · · ·||— · —||—||· · — — —||Comma||— — · · — —||Semicolon||— · — · — ·|
|— · — ·||· — · ·||· · —||· · · — —||Question||· · — — · ·||Double dash||— · · · —|
|— · ·||— —||· · · —||· · · · —||Apostrophe||· — — — — ·||Plus||· — · — ·|
|·||— ·||· — —||· · · · ·||Exclamation||— · — · — —||Hyphen, Minus||— · · · · —|
|· · — ·||— — —||— · · —||— · · · ·||Slash||— · · — ·||Underscore||· · — — · —|
|— — ·||· — — ·||— · — —||— — · · ·||Parenthesis open||— · — — ·||Quotation mark||· — · · — ·|
|· · · ·||— — · —||— — · ·||— — — · ·||Parenthesisclose||— · — — · —||Dollar sign||· · · — · · —|
|· ·||· — ·||— — —||— — — — ·||Ampersand||· — · · ·||At sign||· — — · — ·|
There is no standard representation for the exclamation mark (!), although the KW digraph (— · — · — —) was proposed in the 1980s by the Heathkit Company (a vendor of assembly kits for amateur radio equipment). While Morse code translation software prefers this version, on-air use is not yet universal as some amateur radio operators in Canada and the USA continue to prefer the older MN digraph (— — — ·) carried over from American landline telegraphy code.
The &, $ and the _ signs are not defined inside the ITU recommendation on Morse code. The $ sign code was represented in the Phillips Code, a huge collection of abbreviations used on land line telegraphy, as SX. The representation of the &-sign given above, often shown as AS, is also the Morse prosign for wait. In addition, the American landline representation of an ampersand was similar to "ES" (· · · ·) and hams have carried over this usage as a synonym for "and" (WX HR COLD ES RAINY, "the weather here is cold & rainy").
On May 24, 2004—the 160th anniversary of the first public Morse telegraph transmission—the Radiocommunication Bureau of the International Telecommunication Union (ITU-R) formally added the @ ("commercial at" or "commat") character to the official Morse character set, using the sequence denoted by the AC digraph (· — — · — ·). This sequence was reportedly chosen to represent "A[T] C[OMMERCIAL]" or a letter "a" inside a swirl represented by a "C". The new character facilitates sending email addresses by Morse code and is notable since it is the first official addition to the Morse set of characters since World War I.
Like music, some people seem to have a natural talent to learn the Morse code effortlessly. During World War II it was common practice to gather a few hundred military recruits into a hall, introduce them to the World of “dahs and dits,” and wash out the majority within two weeks. Those remaining “geniuses” became the wireless Aces of the War.
For most students, gaining control over the flow and rhythm of the sounds proved to be an arduous and fearsome task. Code practice machines used at this time consisted of paper rolls about an inch wide that ran past a light source. The rolls were perforated to create, from the electric eye, an almost perfectly sounded string of Morse code letters, numbers and messages. The student was systematically introduced to the character sound, as the instructor called out the letter’s name. Soon another string of dots and dashes was added and another until a dizzying array of dahs and dits swam in the student’s head. Since the practice sessions often lasted several hours or more, errors were practiced over and over and then when the paralyzing test was given, anxiety ran high with frustration and failure common.
Over the years, most students try to learn Morse code in just this same manner. It is no wonder that when the FCC decided to eliminate the code testing for amateur radio licenses that a great sigh of relief came from many long frustrated “would-be” hams.
However, another method appears to have gained many adherents. In the English speaking countries and in other language parts of the world, Morse code is being taught using a mnemonic system that mimics the sound of the code in the language of the learner. The dahs and dits can be heard as simple words and phrases instead. With this method and only forty characters to learn, a high percentage of students succeed at mastery.
It appears that the brain is capable of learning language quite readily when meaning is attached to sounds. Without meaning in the sounds themselves, the brain has no handles to make an attachment, causing the symbols to become hopelessly mixed. A mnemonic device is defined as: “any learning technique that aids memory. Commonly, mnemonics are verbal (such as a very short poem or a special word used to help a person remember something) but may be visual, kinesthetic or auditory. (Wikipedia.com) Mnemonics rely on associations between easy-to-remember constructs which can be related back to the data that is to be remembered. This is based on the principle that the typical human mind much more easily remembers spatial, personal, surprising, sexual, humorous or otherwise meaningful information than seemingly arbitrary sequences.” The seemingly random string of dahs and dits of the letter take on meaning from the associated mnemonic. Thus the letter “D” might be more readily remembered as “Dog did it” instead of “Dah di di.” Attach a picture of a hapless canine and “presto” the symbol is forever remembered.
Persons learning the Morse code this way find that they can master the code in a matter of days instead of months and that there really can be a lot of pleasure in acquiring and using this universal foreign language skill.
Some Keys and paddles
Here are some CW practice programs.
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