Hi-low-hi-low Sound On Some Coils On Gp Extreme

[bklein]

I bought several coils over the years for my GP Extreme and just now am getting around to trying them. I discovered that some DD coils wouldn’t work - they result in alternating high-low tones without sensitivity to any targets. Is this indicating an issue in the coil or more of an incompatibility. The manual says some coils can act erratically - is this that?

[Steve Herschbach]

If the coils are made for the machine then sounds like bad coils to me. Yes, a properly detecting coil picks up targets. It can also be something as simple as EMI if you test at home. I have to drive ten miles to get outside my urban EMI fog if I am serious about wanting to test any PI. Yeah, they can be made to function, but with degraded performance. Anyway, I’d say bad coils or EMI.