Tom
Your information about erse coils is depressing and frustrating but on their website they state they are using CDA 101
and Solen states they are using
≥ 99.99 % Purity Annealed Copper. But so far these are the purest copper coils I can find ,
strange how Capacitors and wires are improving but not coils
other than maybe foil coils over wire ones .
Rob