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Many an amateur radio operator gets their start building things with a code practice oscillator. It is simply a divice that makes a tone when a connection is made. You connect a telegraph key up to it and it makes a sound when the key is pressed. It sounds very similar to what you hear on the radio when either sending or receiving. It is used to practice morse code.
That's all well and good, but ... How do you know if you are sending the morse correctly? Experienced cw (continuous wave, a slightly more technical name for Morse code) operators can often tell who is on the other end by the sound of their "fist." Each sender will send a bit different. Some are really bad. Morse is supposed to be sent in a very specific way. Probably VERY few people are dead on that. The human brain is very good at adapting. But the closer the better.
Since I want to get back into amateur radio and primarily on cw, I decided to design and build the keyalyzer. It's a code practice oscillator, and a lot more. This is all preleminary, so we will see how it actually turns out. The keyalyzer will have a speaker and an LCD with a place to connect a telegraph key (or keyer, I suppose, if you are that kind of person.) It will display text that you then then have to "send" with the key. It will analyze your sending and give you feedback. It can also send Morse over the speaker for you to practice copying as well as be used strictly as a code practice oscillator.
To understand what the keyalyzer does and why we need it, we need to take a look at Morse code itself. Morse code is named after and generally credited to Samuel Morse. It is very clever and extremely efficient. It neatly solves a rather sticky problem; you can transmit a signal that can either be off or on, with no other properties of use. You need to convey information with that signal. By using patterns of on and off to represent characters, you can transmit information. Morse code defines those patters.
One thing to note is that there is more than one Morse code. For many years Western Union, among others, used "American" Morse code. Other countries had their own variations. But somewhere along the line someone devised the "International Morse Code" or IMC. Today, when someone talks about Morse code, they almost always mean IMC.
In Morse, characters are made up of patterns of "dots" and "dashes." A dot means to turn the signal on for a short time while a dash means to transmit the signal for a somewhat longer time. Of course, you then have to have the signal off for some time between the dots and dashes so that you can tell where each begins and ends. Each character defined has its own unique pattern of dots and dashes. But how many dots and dashes should each character have?
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