What does K mean at the end of a Morse message?

K means over: an invitation for the other station to transmit. ITU-R M.1677-1 lists −·− as the invitation to transmit, and radio amateurs end each turn with it the same way.

What is the difference between K and KN?

K invites any station to reply, while KN (−·−−·) means go ahead, but only the station I am working. KN is K and N run together, and amateurs use it to keep a contact between two stations.

Why do Morse courses start with K?

The Koch course on LCWO opens with K and M heard together at full speed. You add one new sign only after you copy about 90 percent correctly, so the first lesson is just these two rhythms.

The Letter K in Morse Code

K is −·−: one short di and 2 long dahs, dah-di-dah. It lasts 9 units.

−·−dah-di-dah

K drawn to time: 9 units, then a 3-unit gap before the next letter.

SpeedSlow · 8 WPMNormal · 18 WPMFast · 25 WPM

Facts about K

Code: −·− · dah-di-dah
Elements: 3 — one dot, 2 dashes
Length: 9 units + 3 before the next letter
Time: 0.54 s at 20 WPM · 1.35 s at 8 WPM
Tree: T → N → K · below it: C, Y
Frequency: 0.54% of English letters, 22nd of 26²
Koch order: 1st sign of the course
Spelling: Kilo
Same signal: К in Russian Morse · Κ in Greek Morse · ワ in Wabun

§ 1Don’t confuse K with

Kthis letterdah-di-dah
Aone element shorterdi-dah
None element shorterdah-dit
Mone element shorterdah-dah
Ufirst element differsdi-di-dah
Dlast element differsdah-di-dit
Oelement 2 differsdah-dah-dah
Xone element longerdah-di-di-dah
Cone element longerdah-di-dah-dit
Yone element longerdah-di-dah-dah
Qone element longerdah-dah-di-dah
Rmirror: every di and dah swappeddi-dah-dit

Blue marks the elements that differ from K.

§ 2How to remember K

KICK-the-CAN (−·−) — K mirrors R (·−·): K begins and ends on a dah, R on a dit.

§ 3Words with K

§ 4Questions about K

What does K mean at the end of a Morse message?: K means over: an invitation for the other station to transmit. ITU-R M.1677-1 lists −·− as the invitation to transmit, and radio amateurs end each turn with it the same way.
What is the difference between K and KN?: K invites any station to reply, while KN (−·−−·) means go ahead, but only the station I am working. KN is K and N run together, and amateurs use it to keep a contact between two stations.
Why do Morse courses start with K?: The Koch course on LCWO opens with K and M heard together at full speed. You add one new sign only after you copy about 90 percent correctly, so the first lesson is just these two rhythms.