Re: tx pop

John Pieper
 

Pete,

Maybe some more experimentation with the capacitor value is needed. The diode has some finite forward resistance so it will take some small amount of time for the cap to charge up. I originally had the circuit connected to U1 input as well and had settled by experiment on 330 nF. Didn't see any change in effectiveness when I moved it to M2. So maybe a somewhat smaller capacitor will fix it. (Don't remember what I have for the resistor, btw). Also by the way, my gate circuit is slightly different. I have only the diode in series with the T/R signal going to the gate. Both the capacitor and resistor are connected from the gate to ground. I seem to remember that I had a hard time getting it to work until I tried it this way. Don't know what difference it might make, though.

For R70, I knew I wanted something larger than 10 ohms to have the voltage divider produce enough output, but not so large that the maximum volume available from the volume pot would be reduced significantly. I saw that I had the 510 ohm part and thought, "try this". Simple as that.

73, John

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