In CQ – January 2018 – Pete, N8PR (SK) wrote that you should set up your receiver to produce two tones 65 to 80 Hz apart to make copying weak CW signals more easily. The theory behind this is that the dissonance between the two tones makes copying a CW signal more copyable than just a single tone. I like this idea. I played around a little bit last night with this technique, and it did indeed seem to work better than using just a single tone.
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