I'll admit there were times when I thought I might never get this thing working, but dogged persistence in the face of frustration will sometimes get the job done. Failure to accept the mushy and hum-ridden audio finally led me to crack the tough nut.
Today, I finally slew the new CC-20 beta dragon. Without getting into a long, drawn-out rant about what went wrong, I'll just say that transcription errors and schematic capture screw-ups did me in. I believe that at least 5 separate problems with this PCB turn were discovered in the end. All of the errors kind of "stacked up" on each other. Solving one would lead to a marginal, but not final improvement. The big problem is that a couple of those were very subtle errors to troubleshoot.
The big one that finally restored the receiver to the glory that it deserves was a missing decoupling resistor in the IF amplifier. That one little change took the audio from minimally functional, low sensitivity, and full of DDS spurs to the clean, sensitive, and spur-free receiver that I knew the prototype to be. Even after I identified the problem, I almost missed the fix because of some kind of strange routing that I did with the VCC line. But enough banging my head against the bench, and I managed to beat some sense into my brain and fix the problems once and for all.
A bit more tweaking finally got the radio ready to go on the air for its first QSO today. Repeatedly calling CQ on 14.060 MHz resulted in no answers, forcing me to wonder if I screwed something else up, like the carrier oscillator alignment. But I heard a strong station a few kHz down and thought I would try to give them a call instead. It turned out to be KD0V in Minnesota, who was blasting in at a strong 599. He gave me a 559 in return and commented that the transmitted note sounded good to him. Due to my frazzled nerves, I kept the QSO fairly short and called it a day after the exchange of the usual information.
So it looks like the beta kit is finally in a state where I can package it and send it out. Many people will be happy with this news; first and foremost being my wife and the long-suffering beta testers. Let's hope for the best during the beta test and maybe I can get out of this without a permanent nervous condition.