This is a two part video: Part 1 shows one way to use a scope, signal generator, and a simple circuit to help you visually tune an HF antenna with an antenna tuner (or via antenna adjustments). Part 2 shows how you can estimate the complex impedance of the antenna system (antenna and feedline) using the same setup. This method should work reasonably well for HF frequencies with a carefully built fixture and setup. Parasitics and other sources of uncertainty will likely start to become significant at frequencies above 30MHz or so. Part 1 runs for the first 9 minutes, and part 2 picks up at the 9:00 mark.
Cool! This video got posted to Hack-A-Day!
Notes from this video can be found here: