NO in Morse Code

N does two jobs at once

N is the negative, and it is also the contest shorthand for the digit 9. That sounds like a recipe for confusion and is not, because the two never turn up in the same place: a signal report is a number, an answer is an answer, and the context settles it before the ear does.

The practice is called cut numbers, and it exists for one reason - the digits are the most expensive characters in the code. Every one of them is five elements long. Replacing them with short letters that share the same shape saves a third of the airtime in an exchange that gets repeated hundreds of times in a weekend:

• T - for 0 -----
• N -. for 9 ----.
• A .- for 1 .----

A report of 599 goes out as 5NN, and 100 watts becomes 1TT. The contest simulator runs exchanges at speed, which is where the saving stops being theoretical.

Three dashes is the other half

O --- is 11 units for the fourth most common letter in English - the clearest mismatch in the whole code between how often a letter is used and what it costs to send. It is also the middle of SOS, and the reason the distress signal has the shape it does: three dots, three dashes, three dots, run together as one character.

A hand that lets the dashes run turns O into the digit 0 -----, which is five dashes. There is nothing between them but the count.

The O page has the timing, and the SOS page the distress signal itself.

Negatives that are not N

Morse has more precise ways of saying no than the word:

• QRV? answered with QRV or not at all - "are you ready?"
• NIL -. .. .-.. - "nothing for you", the answer to "do you have traffic?"
• QRT --.- .-. - - "I am closing down", which is a no to everything at once

The Q-code list has the rest.