Oops, typo, try this: I use polycarbonate for all my "homebrew" coil forms and especially plug in coil sets. A picture of the 80M link coupled tuner coilset and tuner is on the web at: http://www.trailing-edge.com/~shoppa/linktuner.html I am currently winding coils (link coupled) for a push-pull 811A amp set too.