I air tested this effect on three separate pinpointers. The Garrett pro pointer, White's older Bullseye 120mm (has a very boxy housing) and the newer White's Bullseye 2. On both White's I only tried extending the range with a silver rosie dime. But on the Garrett Pro I used a 1/2 by 1/2 single ply of foil, a silver rosie dime, a clad nickel, and a silver half Benjamin. I tested all the pinpointers for distance detecting a silver rosie dime over a wooden ruler edgewise and facewise. I tried to slide the metal object back on the coil until the pinpointer was completely quiet and stable on each test. The trick only effectively extended the range on the Garrett Pro and the White's Bulleye 2. Surprisingly the Older White's Bullseye performed as well a the Garrett Pro in normal operation. Slightly better on the coins edge actually. The extended range effect seems to be affected by the mass and conductivity of the metal object placed against the coil. Observe that the silver rosie outperformed the clad nickel even though the nickel was more massive. And that the more massive silver Benjamin half dollar out performed the silver rosie even though their conductive properties must be very similar. I encourage others to experiment and try to replicate my results.

Normal Operation Extended Range
edge face edge face
Older White's Bullseye 5/8 1 3/16 3/4 1 1/4
(with silver rosie dime)

White's Bulleye II 3/8 5/8 5/8 1 1/16
(with silver rosie dime)

Garrett Pro Pointer
(with 1/2x1/2 foil) 3/8 1 3/8 7/8 2
(with silver rosie dime) 3/8 1 3/8 1 3/8 2 3/4
(with clad nickel) 3/8 1 3/8 1 1/4 2 1/2
(with Benjamin Half) 3/8 1 3/8 1 7/8 4 1/4


p.s. I'd like to thank my friend Steve for letting me use his White's Bullseye 120mm pinpointer.
p.s.s. My table doesn't format correctly on my phone, just on my computer.