From JB(MS) Lady Shadow.

William Monday

Jr. Member
Jul 19, 2014
Primary Interest:
All Treasure Hunting
The "Lady Shadow" ran at 9.6 khz, according to Tesoro, and a sticker/label was included in the box that could be applied, if the buyer chose to apply it, to tell it from the 10 khz Shadow. If one doesn't have the sticker, probably the only way to tell the difference would be to use a scope. As for the same coil working on Tesoro detectors that ranged from the 9.6 khz Shadow to the 15 khz Golden Sabre while Whites, Garrett and Fisher detectors could only use coils with less than a .5 khz difference, I asked Jack Gifford that question back in 1997 or 98. Whether his response was accurate or not I have no idea, but he said they used a variable oscillator, he called it a rolling oscillator, and the coil was part of the circuitry that determined the final frequency. That not only allowed the same coils to be used on a wider range of frequencies it allowed a wider tolerance range when making them . If that was true, it not only means a 10 khz Tesoro isn't exactly 10 khz, it's likely why Tesoro's rarely have interference issues with other Tesoro's with the same stated frequency.


Hero Member
Dec 1, 2012
Peshtigo, Wisconsin
Detector(s) used
Tesoro Tejon, Tesoro Silver uMax, Tesoro Tiger Shark
Primary Interest:
Metal Detecting
A basic oscillator circuit is made from a capacitor and an inductor in parallel. The coil is the inductor and a variable capacitor could easily tune the circuit to a different frequency. Today oscillators are usually made with an op amp using regenerative feedback. I don't doubt what Jack said on that one. Seems like a smart idea by using the same coils for several machines.


Bronze Member
May 16, 2007
Lewiston, Idaho
Detector(s) used
Multiple Tesoros and Whites
Primary Interest:
Metal Detecting
I have to differ on the interference statement as I've run across a fair bit of cross talk from other Tesroros of the same model while participating in competition hunts.


Full Member
May 12, 2009
The Shadow X2 I used to own had either an A or B in the serial number on the detector. If my memory serves me correctly the B at the end of the serial number indicated it was a Lady Shadow running at 9.6 kHz.

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