Adding an NEL Tornado coil to your Garrett Ace 250 can give you many benefits over the stock coil. This includes much greater depth, much increased ground coverage per sweep, much improved target separation in trashy areas and the ability to handle mineralised soil better.
The Garrett Ace 250 is the slightly bigger brother of Garrett’s entry level machine, the Ace 150. It naturally has some extra bells and whistles being the next in the range and slightly more expensive.
Both the Ace 150 and Ace 250 shipped with Garrett’s elliptical shaped “concentric” 6.5” x 9” standard coils. Garrett has superseeded these now with the Ace 200i and 300i respectively.
You can read a little more about the Garrett Ace 250 and alternatives in my article here.
The standard coil that shipped with these detectors can be upgraded with a Garrett Reaper DD coil, a Detech DD coil or an NEL Tornado coil which will transform the detector and increase finds rates.
Entry level machines, as a rule generally ship with concentric coils as they are more easily produced and are more cost efficient.
They work perfectly well albeit differently to some other shaped coils you may have come across. This maybe a good position to quickly explain how metal detector coil types work and how different coils perform.
DD coils vs Concentric coils
The elliptical coil that ships with Ace 250 is effectively a concentric coil which traditionally are circular.
The elliptical shape was a natural progression to give the user slightly more ground coverage with every sweep.
A coil is called so because it basically is a massive amount of coiled copper wire around a shape.
A coil will also always have a “Transmit” coil and a “Receive” coil which are the inner and outer rings.
The coil produces a balanced electromagnetic field when an electrical current is passed through it. This balanced electromagnetic field gets disrupted when it’s passed over a metallic object and becomes unbalanced.
It’s this disruption that gets measured and gives you your signal.
So, now we basically know how a coil works in layman’s terms, let’s get back on track and talk about the shapes of these electromagnetic fields and coil types.
A concentric coil like the one shipped with the Garrett Ace 150 and 250 will produce what is commonly known as an “upturned ice cream cone” shape due the nature of the coil windings.
The maximum detecting depth you can achieve with a concentric coil will be directly in the centre of coil because of the cone shape.
This does mean that there are some things you have to remember when using one.
To get the maximum ground coverage at depth, you don’t necessarily have to sweep at a slower rate, you just need to make sure you reduce you sweep overlaps and keep them tighter.
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This will help reduce the chances of you missing a deeper target at the bottom of the cone.
Another thing to remember is that a concentric coil can sometimes be susceptible to more noise from difficult, mineralised ground.
This is due to the cone shaped field literally “seeing” a bigger chunk of ground under the coil and thus seeing more mineralisation.
As the Ace 150 and 250 have fixed ground balancing, the only way to reduce this would be reduce the sensitivity of the machine.
Some detectorists can fall into the trap of thinking that their sensitivity has to be as high as it’ll go or they’ll lose depth. This is true to a certain extent but I liken it to driving in fog.
You can’t see any further in fog if you put your headlights on full beam, in fact, you make it worse. It’s better to reduce the light and keep on a dipped beam.
You may lose a little depth in tough soil but you’re more likely to miss a target in all the noise if it’s too high! Another way to combat tough conditions would be to swap to a smaller concentric coil.
A DD or “Double D” coil works differently and is a natural metal detector upgrade that can totally refresh and transform a detector. A “DD” coil works by overlapping the coils as opposed to having them concentrically set out.
They are more expensive and difficult to make so usually are the preserve of “mid-range” detectors.
They work differently as the electromagnetic field that is produced isn’t cone shaped, it’s known as a “blade” that stretches from the front tip of the coil to the rear tip.
The field also projects into the ground in such a way that you get maximum detecting depth from front to back.
This means that you get maximum ground coverage with a consistently deep scan.
It also means that when sweeping the search coil, you don’t have to keep the sweeps so tight, thus covering more ground and increasing the chances of finding a target.
Another benefit of DD coils is that because of the “blade” field, they work much better in mineralised soil conditions.
This is because unlike the concentric cone shaped field, the blade shape sees a much reduced soil volume so doesn’t get effected as much. The DD coil is the preferred option for most detectorists.
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Coil upgrade options
So, you maybe here because hopefully you have an Ace 150 or Ace 250 and you want to breathe new life into it. The main way to do this as we’ve covered is by swapping the concentric coil for a DD coil.
Swapping from a standard coil to a much larger, DD coil will most definitely increase your finds rate. Let’s have a look at the popular options to supercharge your Ace 150 or Ace 250.
Garrett 14 x 11 DD Reaper Coil for ACE Series
A massive 14″ x 11″ footprint for great coverage
Submersible in water
What could be better:
Will naturally feel a bit heavier than the standard coil
The Garrett Reaper looks ever bit the predator and provides an instant 25% increase in ground coverage as compared to an 8.5″ x 11″ DD coil.
Due to the extra coverage, this makes this coil perfect for working large fields searching for those deeper, more elusive coins and artefacts.
Because of its larger size, it offers a significant increase in detection depth on medium to large targets while still being sensitive on small targets.
This Reaper is a tough coil and fully submersible coil. It will feel heavier than the standard coil which is to be expected but weighing in at 21.2 ounces, it’s still light enough to swing for most of the day.
DETECH Ultimate Coil 13″ DD For Garrett Ace Series
13 inch scan gives great footprint
Also comes in a 15 inch version!
Provides all round superior detector performance
What could be better:
The supplied coil bolt could be more sturdy but overcome this by using your original stock bolt.
Coming from the Detech stable, you know this coil will be of quality. This is because Detech are specialists in this field. Upgrading with the “Ultimate” coil will give you increased depth (up to 30%) and accurate pinpointing.
When the coil is compared to many traditional DD coils, Detech claim that patented technology provide you with more stability, improved ground balancing and more accurate target identification.
The coil is filled with the latest lightweight resins strengthened with glass fibres.
This makes the 13″ version slightly lighter than the Garrett Reaper and gives it great shock resistance. All Detech coils are waterproof and come with a coil cover to prevent scuffing and wear.
NEL Tornado 12″ x 13″ for Garrett Ace Series
Increased depth by up to 50%
Great in mineralised soils
What could be better:
Can naturally feel heavier than the standard coil
This is what we’ve been waiting for!….the Tornado from NEL. This was the same coil I upgraded to on my old Minelab XTerra 70 and it transformed it.
(In fact, you can see an old grainy test video I produced with my friend here in my video vault!)
The Tornado coming from the well known manufacturer Nel is synonymous with quality and performance.
It provides increased stability and sensitivity for highly mineralised soils and only weighs 560 grammes.
The depth claims can be increased by approximately 50 percent compared to a normal coil. This is definitely a recommended upgrade from the standard coil. The coil is completely waterproof.
If you aren’t in a position to upgrade your Garrett Ace 150 or Ace 250 to a more advanced machine, a coil upgrade is the next best thing you can do.
By swapping the standard concentric coil that was shipped with it, to an increased sized DD coil, you can benefit from increased depth, increased ground coverage, increased stability and better handling of difficult soils.
With the costs of the coils in mind being around the £130-£150, you wouldn’t be that far away from upgrading to a whole new machine.
Typically an entry level multi frequency machine with a DD coil like the Minelab Vanquish 340 can be had for well under £250.
You can read my dedicated article on the Minelab Vanquish series here. Food for thought anyway.
I also have a useful article on finding the best metal detector under £300 here. Good luck and happy hunting!
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The entry level Vanquish 340 now gives you ultimate depth, stability and sensitivity on all target types in every soil, including wet beach sand.