What kind of coil does the TDI come with mono or DD ?
- Thread starter DD coil
- Start date
Jim McCulloch
Jr. Member
Re: What kind of coil doe's the TDI come with mono or DD ?
Currently, the factory and after-market coils made specificaly for the TDI are of mono design. Typically, for conventional PI's, DD coils were needed for use in really "hot" ground which would overload mono coils. However, the TDI is so incredibly stable that DD's are not needed for most locales. But, as you may know, the TDI can be used with various makes of coils made for Minelabs PI machines. With my TDI, using the 12" Dual Field, I have gotten flat nuggets as small as 2.5 grains. With the 7" White's Dual Field, as well as the 10x6 from Jimmy Sierra, I've bagged flat 1.5 grainers. Hope this helps; HH Jim
Currently, the factory and after-market coils made specificaly for the TDI are of mono design. Typically, for conventional PI's, DD coils were needed for use in really "hot" ground which would overload mono coils. However, the TDI is so incredibly stable that DD's are not needed for most locales. But, as you may know, the TDI can be used with various makes of coils made for Minelabs PI machines. With my TDI, using the 12" Dual Field, I have gotten flat nuggets as small as 2.5 grains. With the 7" White's Dual Field, as well as the 10x6 from Jimmy Sierra, I've bagged flat 1.5 grainers. Hope this helps; HH Jim
Re: What kind of coil doe's the TDI come with mono or DD ?
Dear DD Coil;
The DD wound coil produses a blade shaped signal pattern about 1-2" in width, running heel to toe down the centerline of the coil. A 12" DD coil will penetrate roughly 8=9", a 15" DD coil will penetrate down to around 11" and a 17" DD coil about 13". All of these estimates are with the detector/coil combos being used in normal mineralization. Your own mileage may vary.
The round mono coil produces a cone shaped signal pattern, much like an inverted snow cone, with the point of the signal pattern roughly the depth as the diameter of the coil. In other words, an 11" coil should give about 11" or better depth penetration, a 14" around 14" penetration and so on. Once get above the 14" diameter coil, the law of diminishing returns takes over and an 18" round mono will get about 16" depth and and a 25" round mono will get about 20-21" of depth, under normal conditions.
An epilliptcal mono coil also produces a cone shaped signal pattern, however the sides of the cones will be flattened in the same shape as the coils' footprint.
According to Eric Foster, one of the benefits of using a TDI is that it can use mono coils without all of the interference usually associated them. He also states that there is no advantage when using a DD wound coil instead of a mono. Also, he states that all coils which are designed for the Minelab PI detectors, ie. the SD2000, SD2100, SD2200, GPXtreme, GP-3000, GP-3500, GP-4000 and the GPX-4500 will work just fine on the Whites' TDI. IMVHO, this is absolutely AWESOME! Minelab, Coiltek (which I use) and Nugget Finder all make a very wide array of mono coils for these detectors and between all of them, they have just about every concievable size and shape of mono coil you could want, from the just introduced 6" Coiltek mono to the 25" Nugget Finder round mono.
I currently have 12 different coils for my Minelabs and 9 of them are monos, so trust me, when I am in the market for a new detector, the TDI will be at the top of my short list!
Your friend;
LAMAR
Dear DD Coil;
The DD wound coil produses a blade shaped signal pattern about 1-2" in width, running heel to toe down the centerline of the coil. A 12" DD coil will penetrate roughly 8=9", a 15" DD coil will penetrate down to around 11" and a 17" DD coil about 13". All of these estimates are with the detector/coil combos being used in normal mineralization. Your own mileage may vary.
The round mono coil produces a cone shaped signal pattern, much like an inverted snow cone, with the point of the signal pattern roughly the depth as the diameter of the coil. In other words, an 11" coil should give about 11" or better depth penetration, a 14" around 14" penetration and so on. Once get above the 14" diameter coil, the law of diminishing returns takes over and an 18" round mono will get about 16" depth and and a 25" round mono will get about 20-21" of depth, under normal conditions.
An epilliptcal mono coil also produces a cone shaped signal pattern, however the sides of the cones will be flattened in the same shape as the coils' footprint.
According to Eric Foster, one of the benefits of using a TDI is that it can use mono coils without all of the interference usually associated them. He also states that there is no advantage when using a DD wound coil instead of a mono. Also, he states that all coils which are designed for the Minelab PI detectors, ie. the SD2000, SD2100, SD2200, GPXtreme, GP-3000, GP-3500, GP-4000 and the GPX-4500 will work just fine on the Whites' TDI. IMVHO, this is absolutely AWESOME! Minelab, Coiltek (which I use) and Nugget Finder all make a very wide array of mono coils for these detectors and between all of them, they have just about every concievable size and shape of mono coil you could want, from the just introduced 6" Coiltek mono to the 25" Nugget Finder round mono.
I currently have 12 different coils for my Minelabs and 9 of them are monos, so trust me, when I am in the market for a new detector, the TDI will be at the top of my short list!
Your friend;
LAMAR
..........HH.... DD coil
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