U in Morse Code: ··−
The letter U in Morse code is ··−, spoken as "di-di-DAH": two short, then one long. That is 2 dots and 1 dash, with a dash held three times as long as a dot. To remember it, think un-der-STAND (two quick beats, then a stressed one).
Timing: how long each part lasts
Morse timing is built from one unit, the length of a dot. A dash is 3 units, and the silence between the elements of a single character is 1 unit. At 20 words per minute, one unit is 60 ms, so U breaks down like this:
| Element | Signal | Length (units) | At 20 WPM |
|---|---|---|---|
| Dot | · | 1 | 60 ms |
| Gap | (silence) | 1 | 60 ms |
| Dot | · | 1 | 60 ms |
| Gap | (silence) | 1 | 60 ms |
| Dash | − | 3 | 180 ms |
| Total for U | 7 | 420 ms | |
How to signal U
- Tap it: two short, then one long. A short is a quick tap; a long is a heavier tap, or a quick tap followed by a slight hold, about three times as long.
- Blink it: two short, then one long. Use quick blinks for dots and slow, deliberate eye closes for dashes, keeping the rhythm steady.
- Flash it: two short, then one long. Short flashes for dots; for dashes, hold the light on about three times longer. Any flashlight or phone screen works.
How to remember U
Say un-der-STAND (two quick beats, then a stressed one) in rhythm with the code and the pattern sticks: "di-di-DAH".
Words that start with U: Uniform ··− −· ·· ··−· −−− ·−· −−, umbrella ··− −− −··· ·−· · ·−·· ·−·· ·−, under ··− −· −·· · ·−·, unit ··− −· ·· −. The first is U's NATO phonetic name, which operators use to spell aloud.
Add a final dot to U and you get F. Extend it with a dash instead and you reach the accented letter code for a-umlaut/u-umlaut territory in the extended international table.