If you are a ham radio operator of a certain age, you probably remember ads for “The Instructograph,” a mechanical device for learning Morse code. [Our Own Devices] has an ancient specimen of the ...
"Morse code" is used to express letters and numbers by combining codes of different lengths, such as "Ton Ton Ton, Toe". Although it is a Morse code that uses only two codes, it is hard to memorize ...
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