
1. The Early Radio Problem
Back in the early 1900s, before fancy superheterodynes and digital receivers, Morse code was sent using continuous-wave (CW) signals — a steady, unmodulated carrier that was simply on or off.
To the ear, that kind of signal didn’t sound like a tone — it was just silence when off, hiss when on.
Operators needed a way to hear the dots and dashes as actual beeps — something their ears could interpret quickly, even through static.
Enter the Beat Frequency Oscillator. Continue reading










