Quote:
Originally Posted by jr_tech
He speculates that the tuned circuit in the screen grid of the first audio tube may help detect FM audio.
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That's a quadrature FM detector circuit, commonly used in later American tube TV sets. Friend of mine, David K., who grew up in Shanghai in the 50s-60s-70s once told me that he built a TV set by hand, using an electrostatic deflection CRT like one from an oscilloscope (presumably white phosphor). He went back to Shanghai and lost contact with him, maybe this was the circuit he used...
Looking at that schematic a little closer, I don't see the horizontal section.
