Be aware that finding any sort of pure copper in a consumer style cable these days is a losing proposition... even cables sold as "100% oxygen free copper" from name brand makers with a reputation to lose. And then there is that magnetic 100% OFC copper from China... that has 1/3 the conductivity of normal copper... And don't get me started on bogo AWG wire size specs... ever see 16 AWG wire with like 5 hair-thin strands of bogo-copper in it? ------------------ BTW, I understand that TV twin lead, the copper wire type, makes a good test lead for the 3458 measurements.