Guides / On the air

Learning Morse code

Why operators still use CW, how to learn Morse code by sound, how code speed is measured, and the prosigns and abbreviations you will hear on the air.

For everyone. Reviewed against sources October 12, 2026.

Morse code on the air is called CW. The transmitter’s signal is switched on and off in the rhythm of the code, made of short sounds (dits) and long ones (dahs) three times as long (Ethics and Operating Procedures). The ITU notes that Morse code continues to be used in the amateur and amateur-satellite services (ITU-R M.1677-1).

Why CW is still used

  • It is narrow. Measured 6 dB below its peak, a properly shaped CW signal at 25 words per minute is about 100 Hz wide, so the 2.7 kHz taken by one SSB voice signal can hold more than a dozen CW signals. The narrow bandwidth also lets in less noise, which is why, according to the ON4UN and ON4WW guide, long-distance contacts under marginal conditions are most often made on CW (Ethics and Operating Procedures).
  • It is allowed everywhere. You may send CW on any frequency your license class authorizes (47 CFR 97.305(a)).
  • It opens HF to Technicians. Technicians have privileges on parts of 80, 40, 15 and 10 m (47 CFR 97.301(e)), and CW is allowed on all of them (47 CFR 97.305(a)).

Learn the sound, not the chart

Morse code is a pattern of sounds. The ON4UN and ON4WW guide points out that calling the elements dots and dashes makes you think of something visual; the letter R is not “dot dash dot” but “di dah dit” (Ethics and Operating Procedures). The ARRL also advises learning each character by the way it sounds rather than as dots and dashes (ARRL).

Counting dots and dashes works at very slow speeds, but above a few words per minute Morse is most easily read by recognizing the rhythm of each character. An ARRL Laboratory article explains that students who start by counting are forced to switch to rhythm recognition as their speed rises (QEX, April 1990). Both methods below send each character at full speed from the start, so you learn its rhythm instead of counting it.

The Koch method

The Koch method, which G4FON attributes to the German psychologist Ludwig Koch in the 1930s, starts at the speed you eventually want to copy. You begin with just two characters at full speed and add another once you copy about 90 percent correctly, until you know them all (G4FON).

Farnsworth spacing

Farnsworth timing sends the characters at a faster speed than the words: each character keeps its full speed, and extra time is added between characters and words to bring the overall speed down. The idea is to skip the counting phase by sending characters at a speed where rhythm recognition is easy and counting is not (QEX, April 1990). As you improve, the added gaps shrink (G4FON). Some training programs combine Koch and Farnsworth (ARRL).

Practice regularly; the ON4UN and ON4WW guide advises training at the limit of your ability and raising the speed gradually. Once you know the characters, practice copying words and call signs, then real contacts. The same guide notes that experienced operators listen for words rather than letters, and that above about 15 to 20 wpm you should recognize whole words (Ethics and Operating Procedures).

Timing and speed

International Morse code defines all timing in terms of the dot, or dit (ITU-R M.1677-1):

Element Length
Dit 1 unit
Dah 3 units
Gap between elements of one character 1 unit
Gap between characters 3 units
Gap between words 7 units

Speed is measured in words per minute (wpm). The ARRL timing standard uses the word “PARIS”, which is 50 units long including the space after it, as the standard word. Sending that word once a minute is 50 units per minute, so at a given speed one dit lasts 1.2 ÷ wpm seconds, or 1200 ÷ wpm milliseconds (QEX, April 1990). The table applies that formula:

Speed Dit length
5 wpm 240 ms
10 wpm 120 ms
13 wpm about 92 ms
20 wpm 60 ms
25 wpm 48 ms

When CW identification is sent by an automatic device used only for identification, the speed must not exceed 20 wpm (47 CFR 97.119(b)(1)). On the air, 5 wpm is slow enough that you will mostly find contacts on the slow-speed (QRS) frequencies; the ON4UN and ON4WW guide treats 12 wpm as a practical minimum and notes that most experienced operators work at 20 to 30 wpm (Ethics and Operating Procedures). The Morse trainer on this site plays characters at the speed and spacing you choose.

Prosigns

A procedural signal, or prosign, is one or two letters sent as a single character (ARRL glossary); two letters combined this way are sent without the usual space between characters (Ethics and Operating Procedures). The ARRL’s FSD-220 operating card lists the signals below and when to use each (ARRL FSD-220). The sounds are from the ITU recommendation, which lists several of these signals under other names, such as “cross sign” for AR, “wait” for AS and “end of work” for SK (ITU-R M.1677-1).

Signal Sound Meaning on the air (ARRL FSD-220)
K dah di dah Go ahead. Sent after a CQ or at the end of a transmission; any station may answer
AR di dah di dah dit Over. Sent after a call to a specific station, before the contact is established
KN dah di dah dah dit Over, to the station contacted only; no one else is invited to answer
AS di dah di di dit Stand by or wait: a temporary interruption of the contact
R di dah dit Roger: the transmission was received correctly and in full
SK di di di dah di dah End of contact, sent before the final identification
CL the letters C and L Closing the station: going off the air and not answering further calls. Sent after the final identification

One more signal is common in messages: BT (dah di di di dah, the ITU “double hyphen” or =) separates the parts of a message, such as the address from the text (ITU-R M.1677-1).

Operating guides do not all agree on the details. The ARRL glossary also gives AR as “end of message” (ARRL glossary). The ON4UN and ON4WW guide ends a CQ with AR rather than K, ends each turn in a contact with K or KN, ends the contact with SK, and calls combinations such as “AR K” and “AR SK” improper. It also treats KN as two letters sent with a space between them rather than one combined character (Ethics and Operating Procedures).

Common abbreviations

CW makes heavy use of Q signals, abbreviations and prosigns as shortcuts (Ethics and Operating Procedures). You will hear these early:

A short exchange, adapted from an example in the ON4UN and ON4WW guide, might sound like this: “K2ZZZ DE W1ZZZ GE TKS FER CALL UR RST 579 NAME BOB QTH OHIO HW CPY? K2ZZZ DE W1ZZZ K.” The same guide advises never sending faster than you can copy, and not sending faster than the station you are calling (Ethics and Operating Procedures). Answer a CQ at a speed you can copy comfortably, and send QRS if the other station is too fast.

Practice resources

  • LCWO.net runs a Koch method course in your browser and tracks your progress.
  • CW Academy from the CWops club offers training with CW Academy advisors. There is no cost and membership is not required. Training is offered three times a year in two-month sessions: January and February, May and June, and September and October. The ARRL describes these as group code lessons online (ARRL).
  • Morse Code World has browser-based trainers, including instant character recognition drills and a generator with control over the timing.
  • W1AW code practice. The ARRL station W1AW transmits slow code practice at 5, 7.5, 10, 13 and 15 wpm and fast practice from 35 down to 10 wpm, on 1.8025, 3.5815, 7.0475, 14.0475, 18.0775, 21.0675, 28.0675, 50.350 and 147.555 MHz. The schedule runs at the same local Eastern time all year (W1AW schedule), and past sessions are available as MP3 files (ARRL code practice files).

When you are ready for HF, the HF operating guide covers finding a clear frequency and calling CQ, and the band chart shows where your license class may send CW.

Sources

  1. Amateur Service Rules (72 FR 3081) Federal Register
  2. Learning Morse Code ARRL
  3. 47 CFR 97.119, Station identification eCFR
  4. 47 CFR 97.301, Authorized frequency bands eCFR
  5. 47 CFR 97.305, Authorized emission types eCFR
  6. Recommendation ITU-R M.1677-1: International Morse code ITU
  7. A Standard for Morse Timing Using the Farnsworth Technique (QEX, April 1990) ARRL
  8. FSD-220: Communications Procedures, ITU Phonetic Alphabet, R-S-T System ARRL
  9. International Morse Code Training Morse Code World
  10. A Morse Trainer using the Koch method G4FON
  11. Ethics and Operating Procedures for the Radio Amateur (PDF) ON4UN and ON4WW, hosted by ARRL
  12. Ham Radio Glossary ARRL
  13. Communicating with Other Hams: Q-Signals (PDF) ARRL
  14. LCWO.net LCWO.net
  15. CW Academy CWops
  16. W1AW Operating Schedule ARRL
  17. Code Practice Files ARRL