Yesterday, I got the ladder out of the garage and connected the ends of my suspect feedline to my NanoVNA, and observed that there were many, many fine dB of loss on this 20 or so feet of LMR-400. A quick check with an ohmmeter showed that the braid was shorted to the center conductor. Well, that's not good! So, I cut one end off and observed that when I put that one on, I didn't get the center conductor all the way in to the connector. Now that that's fixed and the SWRs are reasonable, communications has been achieved.
I've spent many months, er, years messing around with keyers and keys and radios and, well, ancillary appliances and appurtenances in my shack. In all that time, I haven't done much operating. Why not? Well, because I haven't had even a marginally useful antenna. I've been building a helically-wound vertical that I intend to make multiband by feeding it through an automatic tuner, but my attempt to raise it was a pretty spectacular failure and I've been discouraged since then, although I still intend to see if I can make it work I just haven't had the time or the energy.