Are Small Coils Better Than Large Coils? Are Concentrics Better Than DD Coils?

[Steve Herschbach]

This is not about detector versus detector. It is just a video questioning if small coils are always better in trash, and whether concentrics are always better than DD coils at handling ferrous targets. Too bad about the wind noise. Good stuff though illustrating there are no magic answers.

 

For detailed information see this article VLF Concentric Vs DD Coils

[Desert Dawg]

For nugget detecting small nuggets I much prefer a concentric as the coil has edge sensitivity that the dd doesn't have, you will miss nuggets using a dd in tight quarters. Plus a very small concentric does well enough in mineralized soils where a larger coil may not. I sure wish Minelab would include a concentric small coil in their nugget machine packages.

[Desert Dawg]

As long as you stick with a very small concentric coil it becomes addicting. Its hot all around the edges where the dd is only hot toe to heel down the center. that made the Whites eclipse 5.3 coil very popular for coin/jewelry hunting as well as all I used for tiny nugget hunting was the 3x6 concentric on the GB2. The larger the dd the worse the pinpointing becomes as well. Where the concentrics all center under the shaft to pinpoint no matter the size of the coil. Naturally the larger concentrics are much more vulnerable to mineralization and less desirable for some types detecting.

[EL NINO77]

I did similarly deep 3D tests on my detectors, so I can say that all DD coils smaller than 9" do not passed such a test, but coils of size from 9 "and more -the10",11", 12",13 "coils ... pass such a test well enough or excellent -that is from the detector model and also from the detector setting ...

 

 

And on the other side of the 2D "Nailboard Test" again, this nailboard test will win small,and medium  CC  and DD coils up to size 9",......The size 11",12",13" coils will be much worse to separate.
 

What makes the Elipse DD coils,the  -Whites Eclipse,, Nel Snake, Mars Sniper coils -less deep targets front and rear of the coil easier to separate as the center of the coil...-It's like a concentric coil can also separate the target from the edge of the coil ...

how will the Concentric Coil separate? , Small and medium concentric coils will significantly improve the separation properties - but will not replace the DD coil in every situation...

My advice is to have 2-3 different coils in your detector. Every well-selected coil means you have a "New detector".. ...
 
 

[Desert Dawg]

I will say this about the 8x6 Detech SEF coil, I have a buddy that used to run a concentric small coil for coins in mining camps, he rarely found much, but once he got the Detech 8x6, he got several very nice coins out of those same trashy areas. I guess it boils down to the right tool for the job at hand.

[Guest Tnsharpshooter]

I should have put 11” dd coil on Anfibio Muti unit and tried.  Will show some more things with some videos if it ever decides to quit raining.  Absolutely wettest winter here I have ever seen. Forecast is 5-10” more rain in next few days on top of very saturated ground.  Did hunt today in the rain.  Will post a pic in EQX subforum of what I found.

[kac]

A concentric coil with a small Rx will do better than a DD in very trashy areas simply because the Rx on a dd is elongated so you pick up more stuff around it forcing you to approach the target at different angles. Tesoro has a really nice concentric whereas the Garretts Rx is way too big IMO. 

The small sniper coils just have a small Rx but I think their overall size you sacrifice depth. The span of the coil Tx will determine the depth. Targets are picked up between the Tx and Rx when they impede the signal.

Big downside of concentric coils is covering ground. 

Park hunting and ball fields littered with pull tabs and bottle tops I use the Tesoro, big farm fields, beaches, ponds I use my Garret with a DD. I don't know why companies like Nel / Cors and others don't make medium sized 9-10" concentric coils with a 3" Rx. I think people would do really well with them.

[EL NINO77]

The large 10"-12"-15 "Concentric coils show a lot more mineralization in the  signal from the ground , but they still have a 30-50% scanning surface to their size, so the concentric coils are very good for me when they are small and medium in size 4.5 "-8" coils they have a very good deeph, and symmetry sensor field ... and also have a great sensitivity to small objects ....

 In case of strong terrain mineralization-sweep the CC coil 3-5cm above the ground as usual- you will get better results in detection - you get a better signal-to-ground ratio than the subject's signal in the ground - the detector detects better....

-That's why the  big CC coils are not on the market, but the male CC coils are still on offer ...

...Large 10"-13"-15" DD coils do not have such a problem-they have a large scanning area of 70% -100% -the length of a coil, and the mineralization mainly in the adjustable detectors - I'm working on the contrary :

The large 12"-15"DD coil in the mineralized field sees less mineralization-in proportion to the response from the target in the ground- and has a range as well as a medium 10"DD-and 5-8" small DD coil ... under the same conditions ...and setinngs..-you get more depth .-of targets "coin size"...

The DD coil's disadvantage is an asymmetric scanning field - so often you get a signal and it is idle - when it is swept by a 90 °- other side ....

[Desert Dawg]

The Australians are lucky to be getting those new large dd coils from Nugget finder. With their extreme ground conditions the gpx's will probably  be making some big finds again with the large dd coils that are coming out. I rarely use a dd coil on my gpx unless wet ground in alkali desert, most my hunting areas are medium to mild mineraliization.

[Joe76]

On 3/19/2019 at 5:54 AM, Mxt Sniper said:

The Australians are lucky to be getting those new large dd coils from Nugget finder. With their extreme ground conditions the gpx's will probably  be making some big finds again with the large dd coils that are coming out. I rarely use a dd coil on my gpx unless wet ground in alkali desert, most my hunting areas are medium to mild mineraliization.

Fingers crossed your right about the large Nugget Finder DD's here's a pic of a 8x6 sadie coil in the stomach of the new 25" dd lol