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Table of Contents
Best coil for Garrett AT pro: the 8.5×11” stock coil vs the 5×8” coil
The Garrett At pro comes with a DD 8.5” x 11” semi-elliptical search coil that you can protect with a cover.
It is compatible with all ACE series detectors. So you can use it with the ACE 250, 300i, 400i.
It is waterproof. You can submerge your metal detector up to the control housing.
With a large coil, you get more depth and you can cover a larger area at every sweep. So, it’s a good choice in sparse environments.
But, it’s relatively heavy. It weighs 15.2 ounces. It’s not a good choice for trashy areas.
If you want to work on trashy grounds, you should get a smaller coil. The 5×8” coil is the choice of many detectorists.
Some of them liked it that they kept it as their main coil. They no longer use the stock one.
With a smaller coil, pinpointing becomes easier and faster. It is lighter; it weighs 12 ounces. Like its big brother, it’s submersible.
Less weight means more comfort. Your arm won’t hurt you anymore after using the detector for several hours.
However, with a smaller coil, you will lose some depth. By a rule of thumb, the depth a coil can go is equal to its diameter. That’s why the larger the coil the deeper it can go.
Despite the small loss in depth, many detectorists reported that their recovery rate increased. They managed to find buried metals in spots they already scanned with the 8.5×11” coil.
To wrap up, the 8.5×11” coil is heavier, which means you will get tired faster. It can go deeper. And you can cover a larger area in each swing.
The 5×8” coil is better for trashy areas. It’s lighter and more comfortable to use. Pinpointing becomes easier and faster.
It’s less susceptible to EMI because the receiver coil is smaller. You can adjust the sensitivity to higher levels than the bigger search coil.
The depth will be slightly decreased. Stick the coil to ground as close as possible. To avoid scratching it, use a coil cover.
The smaller coil is highly recommended by numerous detectorists. You can use it for trashy areas and switch back to the stock coil in fields and in the woods.
Or you can keep the 5×8” as your main coil. Or you can use it as a spare emergency coil. In conclusion, you should definitely give it a try.
You can watch this video for a comparison between the two search coils. The detector used here is the Garrett ACE 400.
Installing the new coil
Start by unplugging the 8.5×11” coil from the control housing. You don’t need any tools. You can do it by hand.
Unwrap the coil’s cable. Remove the bolt and wing nut. Now, you can remove the stock coil.
Make sure that the mounting washers are inside the small posts in the stem. Slide the 5×8” coil in place and align its holes with those of the stem.
Wrap the coil’s cable snuggly around the shaft. Garrett recommends doing it clockwise. You can check this article about the wrapping the coil’s cable.
And finally, insert the connector into the control housing and hand-tighten. If you want, you can use zip ties to lock the cable in place.
Using the detector after installing the 5×8” coil
You can turn ON the metal detector. And do some tests to see how is it doing after the coil replacement.
The first thing you want to start with is the depth range of the new coil. A bench test will give you a good idea.
But, a field test is better because the depth range depends on many factors like the size of the buried metal object and the condition of the soil.
To do that, you can bury some metal objects of different sizes and different types of metal (iron, silver copper, gold…) at different depths. Pass the detector over the holes and note the differences.
Since switching between the two coils back and forth takes some time. You can start testing the performance of the metal detector with the stock coil. And take notes of the results. Then do the same with the smaller coil.
This video is about a field test for the 8.5×11” stock coil, the 5×8” coil and the huge 15×17 NEl coil. The metal detector used in this test is the Garret At Pro. He uses also the minelab safari detector.
Another thing that you will notice is that the VDI (Visual Display Indicator aka digital target ID) has shifted. And the audio signal may become a bit different for some metals.
The VDI is a number displayed on the screen of the Garrett At pro. It tells you what type of metal is buried underground based on its conductivity. It’s not available in all the Garrett detectors.
Since the target digital ID will be a little different and the audio signal may also change after replacing the coil, you have to relearn the meaning of the tones and the VDI.
The target IDs of pull-tabs and gold rings are too close. So make sure you note the ID of each one after installing the new coil.
It may be a good idea to avoid using the discrimination and dig everything out until you’re familiar with the 5×8” coil.
Conclusion
The stock coil’s size of the Garret At pro is 8.5×11”. It covers more area and it’s heavy. It may be a good choice for open fields and forests.
The 5×8” coil is lighter and more comfortable to use. It can deal with trashy soil without a problem.
It’s a popular choice for many detectorists. Despite the decrease in depth, many reported that they can recover more items even in spots already hunted with the stock coil.
Tell me in the comments which coil is your favorite.
I purchased the big nel 15” x 17” coil last year. I did an air text comparison against the stock 8.5 x 11.5 coil on a Garret AT Pro using a penny, dime and quarter and actually got more depth with the stock coil than the big nel. Very disappointing, a poor $250 investment. Im not sure if my stock coil is just a very sensitive coil or if my big nel is faulty from the factory. Anyway, i never use the big nel since the sensitivity is less than the stock coil it just sits in the garage. If anyone has an ideas or opinions Im all ears.