Directional cables - what does that really mean?

That might depend....

Are the mini diodes all in series or are they each bypassed with a mini copper conductor?

Also, which impurity in the copper is a semi-conductor?

Germanium....silicon...or some undiscovered element causing this phenomenon?

I need to ponder these things and get back to you.

Be careful. I wouldn’t want you to strain your brain.

If  directionality and "diodes" exist in wire then I should be able to detect pulsating DC on the other end when connected incorrectly.

I don't think it will be a simple measurement like you would with discrete components.  These diodes, if they exist as has been claimed, are distributed in the body of the metal in a way that are not as simple as we could call "series", "parallel" or so on as we would characterize discrete components.  Whatever the effect of these diodes in the signal transmission, it will be elusive and difficult to capture.

Can it be measured?  It's possible but to be honest, it may be as complicated as rocket science.  As Richard Feynman said, if what he did could be explained he probably would not have received the Nobel prize.  If directionality is easy to be measured, you probably would have seen someone done it already.

Just like dark matter, dark energy ... just because we have not seen it directly, it does not mean they may not exist.

Actually, directionality can be measured - and has been measured. Wake up and smell the coffee! ☕️ The preferred direction always (rpt always) exhibits lower resistance. It’s not rocket science. 🚀

Actually, directionality can be measured - and has been measured.

Where’s the data? It has to be actual proven data and not in some guy’s wet dream.  Oh, I got it.  It's one of those "Top Gun" thing where "I can show you but I have to kill you" right?