"I think we're standing on it," George muttered, a shiver running down his spine.
For most hobbyists, a metal detector is a magic wand—wave it over the ground, and it beeps when treasure hides below. But for a dedicated subculture of engineers, tinkerers, and serious detectorists, understanding what happens inside the black box is the real discovery. "I think we're standing on it," George muttered,
This is a well-known, highly technical e-book (often circulated as a PDF) that explains: "I think we're standing on it