Whether you do it with a pencil, in your head or with a computer program, decoding Morse is all about timing. Let’s get started.
Over the next few weeks, I will describe the nuts and bolts of how to write software that decodes Morse code on your PC. In theory, it should be simple, because computers are very good at measuring and acting on timed signals.
In the ideal world, the diagram above tells you almost everything you need to know about Morse code structure. As described in this article, “The word PARIS is used in the definition of code speed because it is the length of a typical word in English plain text, having a total of 50 dot lengths. Each dit is one element, each dah is three elements, intra-character spacing is one element, inter-character spacing is three elements and inter-word spacing is seven elements. The word PARIS is exactly 50 elements.”
So, when we say it’s all about timing, we mean the magic ratio 1:3:7 which describe Morse elements.
What’s more, the magic ratio holds for all Morse speeds. But, as we described previously, our human brains run out of horsepower to track ratios as speed increases.
So, enter software which can track digital signals perfectly as they increase speed by orders of magnitude faster than people send Morse.
All about Timing Imperfections
Unfortunately, hand keyed Morse is imperfect. Very few of us can maintain the magic ratio when we send code. What’s more, we also tend to vary speed of the code we send. So, you need to write software which adapts to the imperfections in real time.
That’s the challenge I decided to take on. Machine sent Morse decodes easily. Hand keyed Morse does not. In future articles, I will describe the various techniques to create an adaptive Morse decoder.