35 terms · plain-English definitions
Morse code glossary
Every Morse, CW, and ham-radio term used on this site, defined in plain English. Bookmark-able.
- AR (prosign)
- End-of-message procedural signal, sent without inter-letter gap. Same code as the plus sign (.-.-.).
- BT (prosign)
- Paragraph break / pause. Same code as the equals sign (-...-).
- Backronym
- A meaning invented after a name exists, like 'Save Our Souls' for SOS. SOS was chosen for its rhythm, not its letters.
- Bandwidth
- How much of the radio spectrum a signal occupies. CW at 20 WPM needs ~100 Hz; SSB voice needs 2,400+ Hz.
- CQ
- 'Calling any station.' The first call when an operator opens for a conversation. -.-. --.-
- CW
- Continuous wave. The technical name for the Morse mode used in amateur radio: an unmodulated tone keyed on and off.
- Dah
- The long signal in Morse. Three times the length of a dit. Written as a dash (-).
- Dit
- The short signal in Morse. The reference length unit. Written as a dot (.).
- DX
- Long-distance contact, especially over oceans or to a rare country.
- Element
- A single dit or dah — the smallest unit of Morse.
- Farnsworth timing
- Character speed at full WPM but with stretched inter-letter and inter-word gaps. Used to learn at target speed without overload.
- GMDSS
- Global Maritime Distress and Safety System. Replaced Morse for ocean distress on February 1, 1999.
- Head copy
- Decoding Morse mentally without writing — the fluent-listener mode for real on-air QSOs.
- IARU
- International Amateur Radio Union. Coordinates amateur radio rules and band plans worldwide.
- IndexNow
- Open protocol for instantly notifying search engines (Bing, Yandex, Naver, Seznam) about URL changes. This site auto-pings on every deploy.
- ITU-R M.1677-1
- The current ITU recommendation defining the International Morse Code (2009). The standard this site uses.
- Koch method
- Learn Morse at full target speed using only 2 characters at first, then add one new character per session as accuracy hits 90%. Implemented at /practice/.
- KN (prosign)
- 'Go ahead, named station only.' Same code as open paren (-.--.).
- MAYDAY
- Voice distress signal (from French m'aidez, 'help me'). In Morse, SOS is preferred.
- NDB
- Non-Directional Beacon. Older aviation navaid; broadcasts its identifier in Morse.
- Prosign
- Procedural signal — two characters sent as one shape with no inter-letter gap. Examples: SK, AR, BT, KN.
- QRP
- 'Reduce power' / 'I am operating at reduced power' (≤ 5 W). A Q-code; also the name of the low-power CW operating style.
- QRO
- 'Increase power' / high-power operation.
- QSO
- A radio contact / conversation between two stations.
- QTH
- 'What is your location?' / 'My location is …'
- Q-codes
- Three-letter abbreviations starting with Q, used in CW operating to ask or answer common questions. See full reference.
- RST
- Signal report: Readability (1–5), Strength (1–9), Tone (1–9). Sent during the contact, e.g. 'RST 599'.
- Service worker
- Browser background script that caches assets. The one in /sw.js makes this site work offline.
- SK (prosign)
- End of contact. Sent at the close of a QSO. ...-.-
- SOS
- Universal distress signal. Three dots, three dashes, three dots (... --- ...) — chosen in 1906 for rhythmic clarity. See full story.
- Unit
- The base time length in Morse timing. A dit = 1 unit, dah = 3, intra-element gap = 1, inter-letter gap = 3, inter-word gap = 7.
- VOR
- Very-high-frequency Omnidirectional Range. Aviation navaid that transmits its ID in Morse. See more.
- WPM
- Words per minute. The standard PARIS-word benchmark for Morse speed. 1 unit ms = 1200 / WPM.
- 73
- 'Best regards' — standard CW sign-off.
- 88
- 'Love and kisses' — informal CW sign-off, usually between op + spouse.
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