H in Morse code

H is the top of the dot ladder. Each extra dot, sent with no gap, makes a new character: one dot is E, two are I, three are S, four are H and five are the digit 5. Nothing but the count tells them apart.

• S:

  ... is one dot fewer. It sounds a touch shorter and lighter than H.

• Five:

  ..... is one dot more. A fifth click before the gap means the digit.

• V and 4:

  ...- and ....- end on a dash, so a long tone at the end rules out H.

• B and L:

  -... and .-.. each turn one of H's dots into a dash.

Counting dots works at slow speeds but breaks down quickly. The aim is to hear H's four-beat buzz as one sound. The Sound-alike drill has a set for exactly this ladder, E I S H 5, and the alphabet chart shows H next to its neighbors.

Any four even, light syllables will do, because H has no dash to stress:

• ha ha ha ha:

  four quick laughs, one per dot.

• hip-pi-ty hop:

  four light beats with no heavy one.

• ears:

  in Douglas Harder's one-word system every letter of "ears" is short, so all four are dots.

There is a phrase for every letter in the guide to Morse code mnemonics.

• Write it:

  four periods in a row, .... with a space before the next letter.

• Tap it:

  four quick, even taps, then a pause three taps long.

• Flash it:

  four short blinks. The light on this page plays at 7 WPM, under three flashes a second, so each blink is easy to count.

A worked example: Hi is .... .., four dots for H, a letter gap, then two dots for I. Without the gap the six dots would run together into one character that the ITU table does not have.

Radio operators write laughter as HI, sometimes doubled to HI HI. Dropped into a contact after a joke, it reads as a chuckle rather than a greeting.

Eight dots in a row, ........, is the ITU error signal, sent to mark a mistake. It is often described as HH, two Hs run together with no gap.

H is also one of only four letters, with E, K and N, whose code survived unchanged from Morse and Vail's original into the international code of 1865.