YES in Morse Code

YES spells out as -.-- . ..., nine elements for a word that gets used constantly. Morse operators, who have been optimising this for a hundred and eighty years, do not send it.

The usual acknowledgement is R (.-.), from "received" — three elements instead of nine, and unambiguous in context. For agreement rather than mere receipt you may see C (-.-.), from the Latin correcto, still used in some procedural traffic. Both are far quicker to send and far harder to mistake through noise.

This compression runs through the whole culture of the code: K invites the other station to transmit, AR ends a message, 73 means best regards. Learning a handful of these teaches you more about how Morse is actually used than memorising another twenty words.

As practice, YES is more useful than its length suggests. Y is -.-- and its rhythm — dah-di-dah-dah — is one of the more distinctive in the alphabet, which makes it a good anchor when you are learning.

It also sets up a genuinely tricky contrast. S is three dots and O is three dashes; together they form SOS. Hearing S against a fast H (four dots) is one of the last distinctions most learners get reliable, because the only difference is a single extra element at speed.

Look both characters up in the Morse code alphabet and play them back to back until the difference stops requiring thought.

• NO in Morse code
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• Morse code alphabet A to Z