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J in Morse Code

J is .--- - di-dah-dah-dah, 13 units, 780 milliseconds at 20 words per minute.

Advanced settings

Farnsworth timing: characters stay at full speed while the gaps between them grow. Set it below the speed above.

Dot / dash / letter gap / word gap -

Durations at the speed set above.

Characters without a Morse equivalent are skipped.

.---

Press play in the box above - J is already in it.

How long J takes

J is 1 dot and 3 dashes. With the gaps that comes to 13 units, number 24 of 26 by length.

  • 5 WPM: 3,120 ms
  • 13 WPM: 1,200 ms
  • 20 WPM: 780 ms

The arithmetic behind them is on the timing page.

What J gets confused with

2 characters sit one element away from J:

  • P .--. - a dot in fourth place instead of a dash
  • W .-- - the last dash missing

J in the tree

  • Built from: . = E, .- = A and .-- = W, then .---
  • Carries on into: no other letter - a leaf of the tree
  • Backwards: ---. = no character at all
  • Koch position: 14 of 26

The tree shows the whole shape, the trainer teaches it by ear.

Why J has this code

J makes up about 0.15 per cent of English text, which is number 23 of 26 by frequency, against number 24 by length. Close enough that the code is doing its job for this letter.

The lengths were set by counting, not by theory - the alphabet page has that story.

J in American Morse

The American code, used on the landline telegraph until the 1920s, wrote J as -.-. instead of .---. That sequence is C in the international code, so the same rhythm meant two different letters depending on which side of the Atlantic you were sitting.

The full table has the other ten.

Worth knowing about J

Add one more dash and J becomes the digit 1. Every digit is five elements long, and four of them start where a letter ends.

Frequently asked questions

Keep going

Alphabet
Chart
Morse tree
Koch Trainer