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Letter 15 of 26 · Oscar in the NATO alphabet
O in Morse Code
The letter O in Morse code is --- (dah dah dah): 0 dots and 3 dashes. Listen to it, learn how to write it, and see the letters it is easily confused with.
Step by step
How to write O in Morse code
Send the 3 signals in order, from left to right. Keep the pauses inside the letter short (one unit) so the receiver hears a single character.
- Dash (dah)
One long signal, three units of time. Then a one-unit pause before the next signal.
- Dash (dah)
One long signal, three units of time. Then a one-unit pause before the next signal.
- Dash (dah)
One long signal, three units of time. Then a three-unit pause before the next letter.
How to say it: "dah dah dah"
Operators never say "dot" and "dash" out loud: they say dit for a dot and dah for a dash, because those syllables have the same short and long rhythm as the signals themselves. Spoken aloud, O is "dah dah dah". Saying it this way while you listen is the quickest way to make the pattern automatic.
Timing of the letter O
Proportional view: teal blocks are sound (dot = 1 unit, dash = 3 units), gaps are silence. The whole letter takes 11 units; at 15 WPM that is about 0.88 seconds.
Do not confuse
Letters that sound similar to O
Most copying mistakes happen between letters of the same length. These are the ones to practice side by side with O.
Examples
Words that start with O in Morse code
Five English words beginning with O, fully translated. Notice how the letter O (---) is followed by a space before the next letter.
| Word | Morse code | |
|---|---|---|
| Ocean | --- -.-. . .- -. | |
| Orbit | --- .-. -... .. - | |
| Olive | --- .-.. .. ...- . | |
| Oak | --- .- -.- | |
| Opal | --- .--. .- .-.. |
About the letter O in Morse code
O is the 15th letter of the alphabet and a vowel. In International Morse code it is written ---, a sequence of 3 signals: 0 dots and 3 dashes. Spoken aloud, that is "dah dah dah". Including the one-unit gaps inside the character, the letter takes 11 units of time to send, where one unit is the length of a dot.
In the classic frequency count of English text, O is the 4th most common letter. That puts it among the nine letters (E, T, A, O, I, N, S, H, R) that make up more than half of everything written in English, so it is worth learning early. When spelling over the radio, operators call it "Oscar" using the NATO phonetic alphabet, which works alongside Morse rather than replacing it.
To send O with a flashlight, keep the light on for one count per dot and three counts per dash, with the light off for one count between them; the light signaling guide has the details. To tap it, use a short tap for each dot and a longer press (or a knock-and-hold) for each dash, as explained on the tapping page. Whatever the medium, the rhythm "dah dah dah" is what makes it O.
FAQ
Questions about O in Morse code
How do you write O in Morse code?
The letter O is written --- in Morse code: 0 dots and 3 dashes, spoken "dah dah dah". Send the signals left to right with a one-unit pause between them and a three-unit pause before the next letter.
How many dots and dashes does O have?
O has 3 signals in total: 0 dots and 3 dashes. Counting the gaps inside the character, it takes 11 units of time to send, which is about 0.88 seconds at 15 words per minute.
What is O in the NATO phonetic alphabet?
In the NATO phonetic alphabet, O is "Oscar". The phonetic alphabet is used for spelling words by voice over radio; Morse code is used when voice is not possible. Both are often learned together.
What words start with O in Morse code?
Any word starting with O begins with ---. For example Ocean is --- -.-. . .- -. and Orbit is --- .-. -... .. -. Use the translator to convert any other word.
Is O the same backward in Morse code?
Yes. --- reads identically in both directions, which makes O one of only four palindromic letters in Morse code, along with K, P, R, X.
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