The completed GPO-2 Secondary Coil.  The coil form is a custom-made one-piece fiberglass shell which is 48 inches tall, 36 inches in diameter at the base, and 18 inches tall at the top.  The custom-made wooden feed-thru insulator is made from birch hardwood.  Note the nylon cap screws that affix the top plate, to eliminate the possibility of corona discharge leakage.       Terry Webster shown polishing the 12 inch diameter hollow copper sphere discharge electrode.