Jamie, when I measured current draw through the QMX +5V PPT line connected to R6 with RF in, the values were quite high at up to ~150mA.? So I then tried injecting the +5V directly to the base of T1 (at D3 cathode end), the currents were more reasonable at no more than ~35 mA and usually quite a bit lower.? The QMX transmitted CW just fine through the amp and I was getting about 20W out on 20M into a dummy load (my QMX puts out ~4W in).? I could stop and start transmitting CW without problems.? I had installed the latest SSB firmware and have the PTT delay set to "50".? I have not played with this setting while injecting PTT-P after D3.?
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FYI, when I tried grounding D5, the current draw was also quite high, so I did not try PTT-N to this point.
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I think this is the best that can be done with my limited knowledge and without major changes to the WA3TFS circuitry.? I am going to hardwire in a TRS jack for connection to the QMX PTT-P output and test some more.
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Then I will test external MIC/PTT operation.? Portable SSB SOTA / POTA operation was my major reason for building the WA3TFS amp.
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73,
Jim - AE5JE
AE5JE - Jim