Walt - The sidetone generator is complete and working well.? The generator circuitry is housed in an external minibox and there are zero modifications to the SX-117 or HT-44.? All connections to the gear are external.? No special parts required other than the high voltage PNP transistor.? I'm not an engineer and I suspect there are more elegant ways to accomplish this, but it does work well for me.? Here is the schematic and a photo of the unit.
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73, Floyd - K8AC
Floyd - K8AC