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I am interested to learn more about the 7.5-inch mono versus the 7.5-inch Aussie coils that are available for the TDI series.  Is there an advantage of one coil design over the other when hunting for nuggets?  I have the standard 12-inch dual field and also a Super Pulse 150 coil and am curious whether I should add either or both of these coils to my collection?  Or should I purchase one of the new Nugget Finder 8x6 Sadie mono coils?  Any thoughts or advice would be greatly appreciated.

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The standard 7.5” coil is a dual field, a smaller coil inside a larger coil. The Aussie version is regular mono, just the outer coil. In theory the small inner coil adds a little extra sensitivity to tiny nuggets, but it’s not much. It also makes the coil slightly more responsive to bad ground; the straight Aussie mono version helps address this, but also loses that little edge on the tiny gold. Note we are talking splitting hairs

The Super Pulse 150 is a 6” round mono, and basically does what the 7.5” coil will do, so you already have a small mono coil. Are you using it a lot? Finding gold with it? Some reason you want another small coil instead? Lots of people like the Sadie coil. But again, how many coils does a person need? I’m a small, medium, and large guy myself, but do not see much reason to have multiples of a particular size.

More About Dual Field Coils

jimmy-sierra-tdi-coils.jpg
search-coils-whites-tdi-metal-detector.jpg

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Steve:

Thank you for your input, information, link and perspective.  Based on this information I will simply use what I have and continue the nugget hunt.  I just wanted to be certain that I had a reasonable selection of coils while they were still available.

Steven

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In what I read and the understanding of the Dual Field and the Mono Aussie is that the Aussie are designed for soils in Australia of high magnetic viscosity or slow signal decay rate.  The Dual Field (12" or 7.5") are designed for soils in North America of being highly magnetic but being faster signal decay. But as Steve said earlier in his post, "... like splitting hairs"

Good Luck and Happy Hunting, TC-AZ

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