J in Morse code

J opens with one short beep and then holds three long ones. Each dash lasts three times as long as the dot, with a silence the length of one dot between them. At 18 WPM the dot is 66.7 ms and each dash 200 ms, so most of J's sound is in its dashes: 9 of its 13 units.

• Say it:

  di-dah-dah-dah, light on the first beat and heavy on the last three.

• Tap it:

  one quick tap, then three taps held about three times as long.

• Flash it:

  one short blink of a light, then three long ones.

• Write it:

  a period and three hyphens with no gaps, then a space before the next letter.

Memory phrases match a letter's rhythm: a light syllable for each dot and a stressed one for each dash. For J, say “in JAWS JAWS JAWS”, one quick word and then three heavy ones. “Let's JUMP, JUMP, JUMP” works the same way.

Douglas Harder's word mnemonics use the shape of the letters instead: a short letter is a dot and a tall one a dash. His word for J is edgy, a short e followed by the tall d, g and y. There are phrases like these for every letter in our guide to memory phrases for the whole alphabet.

Several characters start like J, so the end of the code decides what you heard.

• W:

  one dash shorter, .-- stopping after two dashes.

• The number 1:

  one dash longer, .---- with a fourth dash.

• P:

  the last dash turned into a dot, so .--. ends short.

• B:

  every dot and dash swapped, so -... is J's opposite.

Reversed, J becomes three dashes and a dot. That is not one of the 26 letters; some European operators use it for Ö, which is outside the ITU standard. To train your ear on close pairs like J and 1, try the Sound-alike drill.

J is one of the rarest letters in English, about 0.15% of letters in Robert Lewand's count, 23rd of 26. It arrived late in Morse as well: Friedrich Gerke's 1848 alphabet, the one International Morse grew from, did not tell I and J apart, and J got a code of its own later.

On voice radio J is Juliett, spelled with two Ts so that French speakers do not drop the final t. American Morse, the old landline telegraph code, sent J as -.-., the pattern that International Morse gives to C.

In a word, J gets the usual three-unit gap on each side. JUMP is .--- ..- -- .--. in Morse code, 47 units or about 3.1 seconds at 18 WPM. Type any word on the Morse code translator to hear it, or see J beside the other letters on the alphabet chart.

It is still used, just not where it once was. Morse code was the international standard for ships in distress until 1999, when the Global Maritime Distress and Safety System replaced it. In the United States, the FCC dropped the Morse test for amateur radio licenses effective February 23, 2007.

Today it is most popular among radio amateurs, and aviation navigation beacons still identify themselves with letters sent in Morse. The guide Is Morse code still used? covers where you can still hear it.