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Now that I have my QCX #943 working (mostly properly), I've run into a couple of other issues that Hans might chime in on.

It aligned with the built in TE just fine, got really great sideband suppression, good sensitivity (not quite as good as my K3S but awful bloody close!? I can hear weak signals on the QCX using a much poorer antenna than I have on the K3S so it really isn't a fair test and those signals are also barely readable on the big rig.? That's not the problem though.? Even on a really good precision dummy load (Microwave Associates MA44001, 20 watt, 50 ohm termination good from DC to well over 500 MHz, I get a lot of thumping and no sidetone when keying the QCX - either in keyer mode (Iambic B) or hand key mode using both internal microswitch and an external hand key.?

It sounds like the receiver isn't being muted during key down.? I'm only getting 1.6 watts out so I know for sure I need to tweek the LPF.? I'm wondering if this may also be the reason I'm getting the thumping & no sidetone?? Anyone know for sure?

Jim - W0EB

Disregard my above post please.? I've solved it completely.? The problem was (as mentioned in several other threads) RF feedback.? My QRP antenna feedpoint is about 15 feet above the shack and only 3 feet off the roof of my house.? I hooked the QCX to the big 40 meter dipole that's up 40 feet in the air off my tower.? Cured the problem.? I also re-made all the LPF coils and they are now back to the exact number of turns specified in the manual.? 3.8 watts out on 11 volts and very clean.? Sidetone sounds good.? Finished up the alignment - set the 27 MHz reference frequency as close to exact as I could and not the QCX at least agrees with my K3S on frequency readout.?

Now to build the GPS and get the timing & frequency disciplined from above -- LOL.

Jim - W0EB