https://www.youtube.com/watch?v=NV5hzUO1NWEThanks for that link, Ed, even though YouTub just absolutely must interrupt the program every 90 seconds, right in the middle of a sentence wherever possible, to insert their adverts. Klaus is a thorough experimenter, and a presenter with a subtle sense of humour...a joy to watch.
There are a few aspects of electromagnetics where his theoretical background could be a bit stronger, or possibly he could explain more thoroughly in his native German; but in the clips I watched before my Skip Ad-clicking finger tired out last night, he at least did not seem to attribute any bogus magical properties to "mag loops," the way some of his commenters do.
Using ferrite cores to transform the inherently low impedance of an untuned small loop up to something approximating 50 ohms is, as you know, not that new an idea. Likewise, the use of isolation transformers to break up galvanic paths that would otherwise allow for noise conduction into receiving antennas. Still, it is great to see the actual numbers and the spectrum displays that are "the proof of the pudding" in real-world conditions.
I was also intrigued by his "Möbius loop," which enables one turn of coaxial cable to work as two turns. I vaguely remember hearing of such at one time, but never saw one in actual operation before.