Seventy-five years ago this month, the March 1945 issue of Radio Craft showed this crystal set idea, sent in to the magazine by John Haynes of Doe Run, Missouri. The coil, consisting of about 125 turns of wire, was mounted on a coil form slipped over an old shield can, and snugly affixed with gummed paper. A second can slid over the coil, and was adjusted to tune the set.

The magazine noted that a similar idea appeared in the January 1943 issue of the magazine.