No in Morse Code: Two Letters, Five Signals and NIL

No in Morse code is -. ---. N is dash, dot, and O is three dashes. This page covers no at a glance, a letter-by-letter breakdown, the correct way to write it, how to send no by sound, tapping and light, how NO turns into ON when the letters swap, the NO and NIL signals radio operators use, and how the length of no compares with yes, hi, OK and SOS.

No in Morse Code at a Glance

No in Morse code has 2 letters, 5 signals and a length of 19 timing units. The table below comes straight from the translator’s engine.

A timing unit is the length of one dot. International Morse code, set out by the International Telecommunication Union (ITU) in Recommendation ITU-R M.1677-1, builds every other length from that unit: a dash lasts 3 units, the gap inside a letter lasts 1 unit, the gap between letters lasts 3 units and the gap between words lasts 7 units. No contains 1 dot and 4 dashes, so the signals add up to 13 units and the silences add up to the remaining 6 units. At 20 words per minute (wpm), one unit lasts 60 milliseconds and the whole word lasts 1.14 seconds (1,140 milliseconds).

Letter-by-Letter Breakdown of No

No breaks into 2 letter patterns: N and O. Press the play button beside either letter to hear it alone.

N: dash, dot

-. is one dash followed by one dot, spoken dah-dit. N lasts 5 units. The trap in N is the order of the two signals: dot, dash is A, not N. N and A are mirror images, so a learner who remembers “one dash and one dot” without the order sends AO instead of NO.

O: three dashes

--- is three dashes, spoken dah-dah-dah. O lasts 11 units, which is 11 of the 19 units in no. The trap in O is the dash count: two dashes is M, so a short O turns NO into NM. Keep all three dashes the same length, each exactly three dots long.

How to Write No in Morse Code

To write no in Morse code, replace N and O with their patterns and put a single space between them. The written result is -. ---, with no slash, because a slash only marks the break between two words.

A slash appears as soon as a second word follows. The reply “no thanks” becomes:

There are 4 common mistakes when writing no in Morse code:

1. Reversing N. Dot, dash is A, so the word turns into AO.
2. Dropping a dash from O. Two dashes is M, so the word turns into NM.
3. Removing the space. The five signals run together into a single group that matches no letter, and the decoder returns an unknown character.
4. Swapping the letters. Three dashes first and dash, dot second spells ON, a different word with the same length.

Paste any version into the Morse Code Translator before you copy it, and check that N and O come back as two separate letters.

How to Send No by Sound, Tapping and Light

To send no by sound, play a short beep for the dot and beeps three times as long for the four dashes, with a 1-unit silence inside each letter and a 3-unit silence between N and O. Press Play on the answer card at the top of this page to hear no as a continuous wave (CW) radio tone.

There are 3 speeds most learners use, and no takes the following time at each:

• 5 wpm: a 240-millisecond (0.24-second) dot, and no takes 4.6 seconds.
• 13 wpm: a 92-millisecond dot, and no takes 1.8 seconds.
• 20 wpm: a 60-millisecond dot, and no takes 1.1 seconds.

Say the rhythm aloud before sending: dah-dit, dah-dah-dah. The homepage timing rules explain how the unit changes with speed.

To tap no, use a quick tap for the dot and a press held three times longer for each dash. No is a dash-heavy word, so the dashes carry the message: a listener who cannot tell a held press from a quick tap hears five identical taps. Use a touch surface that shows duration, or knock harder for each dash when the surface cannot. The tapping guide covers both methods. The demonstration below taps no at a slow speed.

To flash no with a light, keep the light on for 1 unit for the dot and 3 units for each dash. A unit of half a second (500 milliseconds) is readable across a room, and at that unit no takes 9.5 seconds. Blinking follows the same pattern at a 1-second unit, where no takes 19 seconds: one long close and one short close for N, then three long closes for O.

NO Backwards: ON and the Mirror Letters

Swapping the two letters of NO gives ON, and reversing every signal of NO gives OA. The two reversals are different operations, and the engine shows both:

All four versions last 19 units, because each one uses the same 1 dot and 4 dashes. Duration alone never tells NO from ON, so the order of the signals and the position of the letter gap carry the whole meaning.

O survives any reversal because three dashes read the same in both directions. N does not survive: the reversed N pattern is A. The 26 letters of the English alphabet fall into 3 groups when their signals are reversed:

• Palindromes (11 letters): E, H, I, K, M, O, P, R, S, T and X read the same backwards.
• Mirror pairs (12 letters): A and N, B and V, D and U, F and L, G and W, and Q and Y swap into each other.
• Accented results (3 letters): C, J and Z reverse into the patterns for Ä, Ö and Ü.

Each mirror pair shares the same signals in the opposite order, so the order of the dots and dashes is the only thing that separates the two letters. The Morse code tree places A and N on opposite branches of the same level, which makes the pair easy to separate.

How Radio Operators Say No in Morse Code

Radio operators say no in Morse code with the two-letter group NO. Recommendation ITU-R M.1172, the ITU list of miscellaneous abbreviations and signals, defines NO as no (negative).

The table sets NO beside NIL and beside C, the opposite answer:

NIL is not a refusal. NIL tells the other station that no traffic is waiting. NO answers a question in the negative. M.1172 also lets an operator send NO right after certain Q codes to give them a negative sense, while C gives the same Q codes an affirmative sense. The Q codes guide explains how the question mark changes a Q code from a question into an answer.

A lone N is not the standard negative. N has other jobs in amateur CW: N stands in for the digit 9 in the contest signal report 5NN, which means 599, and N starts common abbreviations such as NR for number and NW for now. The CW abbreviations guide lists these forms.

How Long Is No Compared with Yes, Hi, OK and SOS

No lasts 19 timing units, which is 6 units shorter than yes and 4 units shorter than OK. The table compares no with 4 other short words, using figures from the translator’s engine:

No has the fewest signals of the five words, 5, but not the shortest length. HI uses 6 signals and still finishes 6 units sooner, because HI is all dots. O is the reason no is not shorter: three dashes and two gaps make O 11 units long, while the four dots of H take only 7. The yes and no pair matters most in practice: the Yes in Morse code page shows that the first 4 signals of YES and NO are identical, so the 3-unit gap after N is what separates the two answers.

SOS is 8 units longer than no. SOS is a distress signal rather than an ordinary word, and the SOS in Morse code page covers when and how to send it.

Practice No in Morse Code

No in Morse code is -. ---: 2 letters, 1 dot, 4 dashes and 19 timing units. Learn the letter-by-letter breakdown with N in the right order, write no with a single space, and send it by sound, tapping and light with every dash held to 3 units. Remember that ON uses the same signals in a different order, that NO is the ITU signal for no, and that NIL means nothing to send. The Morse code words hub lists the rest of the common words, including hi.