Depth Tests For Big Gold Nuggets.

I am aware of a guy here in Victoria who builds CC coils to suit GPX, and according to my mate Mr. Beatty, they out perform any other coil he has seen. Unfortunately this gentleman cannot be tempted, or talked into producing one for my good buddy. (yet)
PS I would dearly love to try one on a QED.

Is it a true concentric Reg or a folded figure 8 mono that some call a concentric type coil even though it essentially has only one winding?
A type of concentric is available for PI's. I believe that the AI or salt coils have an outer seperate tx winding & internal figure 8 rx winding to cancel noise & ground.
If true concentric coils were viable for PI's you'd think NF &/or Coiltek would be all over it?

So , does the Coiltek 18"AI have the same depth on big Nugs as the 18"DD ,,,, but obvoisly would be far less sensitive to smaller nugs ?????

mbasco, I have seen photos that JR Beatty took of the coil, and it looked like a concentric coil to me, but I'm no expert. Beatty would be able to give you more info on it.

White's are doing what looks like CC for the TDI, but it is a dual field mono, meaning two mono's in one to get better sensitivity to small and large targets.

Candigger said:

White's are doing what looks like CC for the TDI, but it is a dual field mono, meaning two mono's in one to get better sensitivity to small and large targets.

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I had one and never found any gold with it..... great beach coil though.

Reg Wilson said:

The photo I saw was of a long slug that looked like it may have been acided. It looked pretty clean for gold that I have seen from that area. I do not doubt that it is authentic, but did not hear of a larger piece.

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Yeah i seen a photo from the buyer of a 220 ouncer, 6kg found mid last year and it was roughly from elbow to wrist in length. Don't know if its the same one your talking about Reg but it was supposedly found by 2 amateurs and found amongst rubbish. Kingower area??

Candigger said:

White's are doing what looks like CC for the TDI, but it is a dual field mono, meaning two mono's in one to get better sensitivity to small and large targets.

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Yes the dual field is basically a folded mono that many believe is similar to CC but only has one winding not inner & outer seperate windings. The dual field coils were a disappointment on goldfields in Australia from what Whites PI users say.
Miner John does a better job with these type of coils but some good testing done by a member here shows they aren't really any more sensitive than coils like the NF Sadie for example.
https://www.prospectingaustralia.com/forum/viewtopic.php?id=21209

mbasko said:

Candigger said:

White's are doing what looks like CC for the TDI, but it is a dual field mono, meaning two mono's in one to get better sensitivity to small and large targets.

Click to expand...

Yes the dual field is basically a folded mono that many believe is similar to CC but only has one winding not inner & outer seperate windings. The dual field coils were a disappointment on goldfields in Australia from what Whites PI users say.
Miner John does a better job with these type of coils but some good testing done by a member here shows they aren't really any more sensitive than coils like the NF Sadie for example.
https://www.prospectingaustralia.com/forum/viewtopic.php?id=21209

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There are actually two separate windings in the White's CC and they are connected in series with separate shunt resistors.
https://patents.google.com/patent/US7994789B1/en

Interesting - I had read before that the dual field was folded to give an inner & outer. Obviously incorrect.
Regardless the windings are still connected & it operates differently than a CC i.e. no seperation of tx & rx. They also didn't work well on Australian ground to the point that they were replaced on Australian TDI's (TDI OZ) with a standard mono coil.
Any Australian reports on these dual field coils from users here always seem to recommend using other coils such as Razorback/Miner John, NF or the newer Coiltek TDI coils.

ozziegold said:

Your question above; yes new DD's will bring some advancement shortly, but I don't see a commercial CC coil for quite some time yet.

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Hi ozziegold.
There are rumours that NF will bring new 25"DD. I know there is 24" DD from Coiltek that is about 2 kilos in weight. Any idea what the weight of the new NF 25"DD will be?

It's not a rumour:
https://www.nuggetfinder.com.au

Nugget Finder said:

A new Range of DD Coils for 2019

Sizes will Include 15" Round, 19" Round & 25" Round

Features Include

-Spiral Winding- Lightweight- Excellent Signal Response

-Quiet Operation in Highly Mineralised Ground

- Fantastic Ground Coverage atMaximumDepth

https://www.nuggetfinder.com.au

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No word on final weights yet but NF are well made & light for size in comparison to other brands.

mbasko said:

It's not a rumour:
https://www.prospectingaustralia.com/forum/img/member-images/4485/1551474397_15514743616560.jpghttps://www.nuggetfinder.com.au

Nugget Finder said:

A new Range of DD Coils for 2019

Sizes will Include 15" Round, 19" Round & 25" Round

Features Include

-Spiral Winding- Lightweight- Excellent Signal Response

-Quiet Operation in Highly Mineralised Ground

- Fantastic Ground Coverage atMaximumDepth

https://www.nuggetfinder.com.au

Click to expand...

No word on final weights yet but NF are well made & light for size in comparison to other brands.

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Looks good, but by the look of the design I would expect at least 1.5 kg of weight with the coil cover.

If they can get it in under 1.5kg I reckon they'll be doing well mate.

So will the new Nuggetfinder flat wound DD suffer this refraction the same as the flat wound monos or do the flat wound DDs punch through the near field mineralization as did the older type DDs?
The reason I ask is I run a 2000 with an old 24 inch coiltek DD and am very happy with that combo, but if the 25 inch DD proves to punch substantially deeper then I will be very interested indeed!

Chris

The 25" DD is out now. See here for a few specs: http://phasetechnical.com.au/product/nugget-finder-x-search-25dd-coil/

Estimated weight is 1.65 kg. But when you pick it up, it feels light for its size.

Got a few spots in mind to test it out on, just need some time and the rain to go away.

It is half spiral, half bundle would, so should handle mineralised soils really well. I will also be testing it on a GP3500 and SD2100 to see how it teams up with them.
Build quality is typical first class from Nugget Finder.

Now we're talking! have some spots tailor made for that!

I would be interested to see how it compares to the old bundle wound Coiltek 24 inch DD on targets that replicate nugget sizes over 20oz and particularly over 100oz.
My thoughts lean towards the fact that as it is dual bundle and spiral wound, giving it more sensitivity towards smaller (sub 5oz) gold, that the trade off would be outright depth on the 100oz+ gold.
Time will tell I guess once people start posting the comparisons.

Chris

PhaseTech said:

The 25" DD is out now. See here for a few specs: http://phasetechnical.com.au/product/nugget-finder-x-search-25dd-coil/
Estimated weight is 1.65 kg. But when you pick it up, it feels light for its size.
Got a few spots in mind to test it out on, just need some time and the rain to go away.
It is half spiral, half bundle would, so should handle mineralised soils really well. I will also be testing it on a GP3500 and SD2100 to see how it teams up with them.
Build quality is typical first class from Nugget Finder.

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Nenad, I will be keenly watching for your test results on the SD2100 ... Im chompin at the bit to get my big 21x17 SEF dirty on golden soil. be good to compare results!

PhaseTech said:

The 25" DD is out now. See here for a few specs: http://phasetechnical.com.au/product/nugget-finder-x-search-25dd-coil/

Estimated weight is 1.65 kg. But when you pick it up, it feels light for its size.

Got a few spots in mind to test it out on, just need some time and the rain to go away.

It is half spiral, half bundle would, so should handle mineralised soils really well. I will also be testing it on a GP3500 and SD2100 to see how it teams up with them.
Build quality is typical first class from Nugget Finder.

https://www.prospectingaustralia.com/forum/img/member-images/3149/1560299146_25_dd_xsearch_2.jpg

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G'day Nenad, is there any talk of a smaller such coil in the wings? 25" is awfully big for the scrub around the GTV...