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Tdi Pro Coil Comparison On The Goldfields


karelian

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On 9/3/2019 at 4:40 AM, karelian said:

I haven't tried any of the flat wound Evo coils,  nor the Detech 11' Ultra. Last coil I ended up buying was the Detech 8 mono which impressed me a lot. Probably nearly as good or equals the Sadie on the small targets and has a small advantage on larger deeper targets. I suspect the round coil shape has a lot to do with that. I use it on the beach and in wet/muddy areas because that Detech is a solid little thing and waterproof, it gets all the dirty jobs. The Sadie doesn't see mud or water.   I'm in the process of culling coils at the moment and that will finance new technology. The mono 8' and Sadie are both keepers. Ground coverage and small gold sensitivity are a winning combination so I can see how the flat wound coils appeal. Karelian

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How would the 7.5" White's dual field coil fare with the 8" Detech mono?

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The duel field coils do well in low to moderate mineralization, but when the soil is hot in Australia they transmit more ground noise and are more difficult to ground balance than mono coils;  in my experience. This is particularly true for the larger coils and less so for the small ones. I only have experience with the White's 12" duel field and the Jimmy duel field coils. Most of the mono coils beat the duel field Jimmy  in Australian soils. The Sadie was the best of the small coils and the Detech equals it. Slight advantage to the Sadie on small gold and slight advantage to the Detech on larger deeper targets. 

If the Jimmy coil is equal to the  7.5" White's duel field then I can say the Detech 8"  which is near identical to the Sadie mono, will have a clear advantage in hot ground encountered in Australia. This would be  reflected in the coil chart results between the Jimmy and Sadie.  Hard won life lessons, plus an army drill instructor have pointed out that behind every stuff up there is an assumption. The above opinion is based on at least one assumption... since I've never seen or used the White's 7.5" duel field coil, only the Jimmy. Also White's didn't promote the duel field coils in Australia, instead providing the mono versions on local machines. Jim In Idaho has posted a video comparing the White's 7.5" duel field and Sadie in the USA, probably more useful than my Australian experiences. Seems that in the US soils,  the performance is very close.. Type of ground and levels of mineralization seem to be the determining factor in Australia and probably also in hot US ground.  Hope this is not a confusing or contradictory answer and is useful to some degree. 

All the best, Karelian

 

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38 minutes ago, karelian said:

The duel field coils do well in low to moderate mineralization, but when the soil is hot in Australia they transmit more ground noise and are more difficult to ground balance than mono coils;  in my experience. This is particularly true for the larger coils and less so for the small ones. I only have experience with the White's 12" duel field and the Jimmy duel field coils. Most of the mono coils beat the duel field Jimmy  in Australian soils. The Sadie was the best of the small coils and the Detech equals it. Slight advantage to the Sadie on small gold and slight advantage to the Detech on larger deeper targets. 

If the Jimmy coil is equal to the  7.5" White's duel field then I can say the Detech 8"  which is near identical to the Sadie mono, will have a clear advantage in hot ground encountered in Australia. This would be  reflected in the coil chart results between the Jimmy and Sadie.  Hard won life lessons, plus an army drill instructor have pointed out that behind every stuff up there is an assumption. The above opinion is based on at least one assumption... since I've never seen or used the White's 7.5" duel field coil, only the Jimmy. Also White's didn't promote the duel field coils in Australia, instead providing the mono versions on local machines. Folks have posted videos comparing the White's 7.5" duel field and Sadie in the USA, probably more useful than my Australian experiences. Seems that in the USA  soils,  the performance is very close.. Hope this is not a confusing or contradictory answer and is useful to some degree. 

All the best, Karelian

 

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I have not found any USA comparisons to date in my searches. Only the one called ridge runner says 7.5  dual field is blind as a bat.lol

Detech doesn’t list the 8” for TDI, just gpx, sd, Minelab detectors. That’s confusing!  I’m in southern Oregon. The soil can get nasty with hot rocks, serpentine, and other types. It is a big dive at the prices that they want without being sure that the improvement will be worth it.

The Detech is waterproof, the Sadie isn’t apparently. 

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The Detech works well with both Tdi Pro and Tdi SL just don't advertise it I guess.  I had the opportunity to try and then buy. . If your coil is stable and performs quietly etc in your soils then performance improvements will be marginal or insignificant. If the duel field is noisy and unstable in your ground then a mono will see improvements across all fronts. Again Jim In Idaho made a video doing a direct comparison, could answer some of your questions. 

 

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2 minutes ago, phrunt said:

I'm not sure if Nugget Finder still produce the Sadie, It's no longer on their website. The smallest coil available on their website is the 12x8" EVO which is flatwound rather than the Sadies bundle wound, Evo's are also waterproof.

From what I've seen the 14x9" EVO appeared to be more sensitive to small targets than the Sadie so the 12x8 must be a pretty good coil.

https://www.nuggetfinder.com.au/products

Nugget Finder seems like they've dropped all the Advantage bundle wound series in favor of the EVO's.

So they’re ok on TDI sl’s?

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Still plenty for sale in Australia, new and second hand. Evo could be the future, I'll get around to trying one after I've completed my coil cull.. Karelian

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PhaseTech is a dealer in Australia and has tried the Evo coil on a customer Tdi, seemed to run well. He mentioned it earlier in this thread. He had a good reputation for calling it the way it is, so I'd say it's probably more than just OK. Sadie has well established reputation on Tdi machines, Evo coils also on GPX whilst new to TDI series.. takes us back to PhaseTech who could provide more relevant info. Karelian

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Video on 7.5DF and Sadie comparison here:

 

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PMC also made a few high inductance coils for TDI's back in 2014-15, very rare beasts. My Brother has a 12x4 Nuggeteer and a  18x14 Scarab and has gotten quite a few nice deep nuggets with the Scarab in particular. 

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