Thread: Morse Pitch
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Old 19th May 2020, 6:27 pm   #13
Radio Wrangler
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Location: Fife, Scotland, UK.
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Default Re: Morse Pitch

Many toroidal 88mH inductors were removed from long phone lines when digital PCM took over. These went to the amateur world and got turned into many an audio filter.

They were 'build-out' chokes to fix an inconvenient issue of the line inductance/capacitance ratio per unit length being wrong for the impedance they were operated with.

Have a shufti at some of the many articles on using these and a quick sim will tell you the frequency if the article does not. It'll give an idea of the beat tones being chosen.


David
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