OK; so I'm paranoid.
I'll admit that I was bothered by making no contacts yesterday for QRPTTF. Even though I was certain that all my equipment is OK; I still had to check it out today. So after mowing the lawn and performing a few other chores, I set up the K1 and PAC-12 in the backyard to reassure myself that nothing was broken.
As soon as I attached the coax to the K1, I could tell the difference. 20 Meters had way more signals on it than I was able to hear yesterday. I even worked a couple of Florida QSO Party stations just to be sure; and had no problems being heard on the first call.
I did do two things differently than yesterday; but neither in and of themselves (or even together) should have made the difference. First, I used three aluminum sections between the feed point and the multiband coil instead of two. This got the coil and the whip higher into the air. Second, I used my more robust home made radials other than the ones that came with the PAC-12. The commercial ones are made of ribbon cable; mine were made from 22 gauge speaker wire.
I would hazard a guess, then, that the location I was at yesterday was pretty much an RF black hole. You run into those, sometimes, when operating portable. I should have known better; but it's always nice to know that it's not a hardware problem - just a software problem (operator's brain).
73 de Larry W2LJ