C in Morse code is —·—·, written as -.-.. Every licensed radio operator, aviation controller, and military communicator worldwide uses this exact pattern — it is the ITU-R M.1677-1 international standard, unchanged since the early 20th century.
Why C Has a 4-Signal Code
Alfred Vail designed the Morse code encoding in the 1830s by counting letter frequency in a printer's type case. Common letters got short codes; rare letters got long ones. C appears in roughly 2.8% of English text — the #12 most frequent letter — which determined its 4-signal code.
For comparison: E (the most common at 13%) gets one dot. Q (0.1%) gets four signals. The system is efficient by design — it was built for a world where telegraph operators were paid per word and transmission speed determined commercial value.
Memory Trick for C
DAH-dit-DAH-dit — "CHAR-lie CHAR-lie" rhythm.
Do not memorise what it looks like — memorise what it sounds like. Tap it on your desk while saying "dit" for dots and "dah" for dashes. Then use the Play button on the Translator and listen to C repeatedly. Your goal is to hear the pattern and think C with no intermediate step — the same automatic response you have when you hear spoken words.
In the NATO phonetic alphabet, C is spoken as "Charlie" on voice radio — chosen because it cannot be confused with any other letter name over a noisy channel.
Learning C With Related Letters
C (-.-.) is a 4-signal letter. Other letters in this group: B, F, H, J, L, P, Q. Learning letters by signal-length group is faster than learning them alphabetically — once your ear knows what 4 signals feels like, you only need to distinguish the pattern within the group.
The Learn page introduces C in Lesson 2 — introduced after the most common letters. Each lesson uses audio flashcards: hear the signal first, then identify the letter.
Words Starting With C
Practising letters inside real words builds stronger memory than drilling them in isolation. Use the Translator to hear any of these words at adjustable WPM — start at 5 WPM and increase as each speed becomes comfortable.
Sending C in the Two-Button Practice Mode
In the Two-Button Practice mode, left button = dot, right button = dash. To send C: right → left → right → left.
The gap between signals within C is one unit. The gap after C before the next letter is three units. Between words, seven units. These ratios must be consistent — incorrect timing makes even correct patterns ambiguous to a receiver.
Real-World Uses of C in Morse Communication
C-prefix amateur radio callsigns. Appears in CQ (calling all stations) — the most transmitted Morse sequence.
If you are studying for an amateur radio licence or planning on-air CW operation, C will appear constantly. The Ham Radio Morse Code guide covers the full path from learning to operating, including how callsign identification works and what to expect in a standard CW contact.
A Practice Plan for C
Spaced repetition — returning to the same material at increasing intervals — is the most efficient way to build durable recognition:
- Day 1: Learn C (-.-.) — audio only, use the Translator, 10 minutes
- Day 2: Drill C alongside one letter you already know in Practice mode
- Day 4: Practise C in words — type words starting with C in the Translator
- Day 7: Test recognition speed in the Quiz — C appears from Level 3 onward
The target: hear DAH-dit-DAH-dit and think C before your conscious mind has processed it. That automatic response is what makes Morse code usable at real operating speeds.
C — The Double Rhythm
C (—·—·) has a distinctive two-pair rhythm: long-short, long-short. "CHAR-lie CHAR-lie" is the standard mnemonic. Once you hear this pattern a few times, C becomes one of the easiest letters to identify — the alternating structure is memorable. C is the first letter of CQ (—·—· ——·—) — the most transmitted Morse sequence in the world. Every time an amateur radio operator calls CQ, they are starting with the C pattern. If you can recognise C, you are already recognising the start of the most common on-air call.
In NATO: Charlie. In aviation: C-XXXX callsigns are Canadian aircraft. The C in CW (Continuous Wave — the term for Morse code on radio) is part of the vocabulary you will encounter in every ham radio conversation about Morse operation.
From Learning C to Real Morse Communication
Knowing C (-.-.) is one piece of a larger picture. The Learn page introduces C in the context of related letters — you never drill it in total isolation. The Two-Button mode presents C randomly alongside other letters you know, forcing genuine recognition rather than sequential anticipation. The timed Quiz tests whether you can identify C quickly enough to be useful in real communication.
At 2.8% frequency (#12 most common letter), C appears moderately often in any Morse text. Solid C recognition, while not as critical as the highest-frequency letters, contributes to your ability to decode any English text.
Use the Translator to hear C in context — type words containing C and listen at 8–12 WPM. The Alphabet page shows C alongside every other character for reference. The Abbreviations page covers the Q-codes and CW shorthand where C appears in operational contexts.