On Nov 9, 2022, at 13:42, Lance KJ5O <joe@...> wrote:

I think I have a problem with my QDX: It seems to be hard of hearing. It's not quite deaf, as I can get, just barely, some signal on the lower bands (80, 40). With a dummy load on the QDX, if I transmit at 100mW on a separate TX into a dipole, I can see the signal being received on QDX quite strongly, so it looks like most things are working, but not well.

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It's a Rev 4 PCB, so it has the C71-C74 mod done prior to being shipped.

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Transmit seems fine.

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I've rewound L12 (first time had miscount on turns) and L2 (twisted the 3 wires tighter) and verified all the continuity tests noted in the assembly manual.

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The self-diagnostic tests seem fine, screenshots included below.

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But on WSJT-X, the waterfall stays empty. In fact, the noise level doesn't seem to change at all (all bands) with nothing connected to the BNC, vs. a 20m resonant dipole, vs. a 50ohm dummy load.

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If I put my finger on L12, the noise floor goes up and on occasion I will see a signal that wasn't there before.

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I'm not sure where to go next. It doesn't feel like the receiver should be this quiet, though.

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