Garrett's Power DD Coil
By Bill G. Revis
From Page 43
May, 2003 issue of Lost Treasure

When Jack Lowry at Garrett Electronics called a few weeks ago and informed me that he was sending me a prototype of a new Double-D coil, I could hardly wait to see what innovation the people at Garrett had cooked up for the further enjoyment of Garrett users.

Garrett Electronics is the house that innovation built, from the days when a young Charles Garrett tired of pursuing his love of treasure hunting with an old, cumbersome, inefficient, World War II mine detector, sat down in his garage workshop, designed and built a metal detector. The rest of course is history.

Garrett is customer oriented and has a long track record of listening to its customers. When Garrett users expressed a desire for a coil that would punch through the toughest of ground and reach those deep goodies, the electronic wizards went to work and conjured up just such a coil--the new Power DD Coil.


This new coil is a 10x 14, coal black, epoxy-filled, open, semi-spider, powerhouse, designed to punch through the worst of ground conditions and provide nearly twice the depth that a standard coil would get in the same conditions. Designed with the relic hunter in mind, this new coil is also a welcome addition to the arsenal of the coin shooter, prospector, and beach and surf hunter.

The major difference between the PDD and most other large coils is the design itself. Most coils available are concentric coils, consisting of two coils, one smaller and placed inside the other. These coils produce an inverted cone signal that narrows almost to a point at peak depth, requiring the user to overlap each sweep by 50 percent or more to even come close to complete coverage. At the peak of detection, an eight-inch coil may only be covering an area the size of a quarter, leaving a lot of targets unearthed.

The PDD coil consists of two coils, each in the shape of a large D, back to back and overlapping each other, forming a narrow strip down the center of the coil. This produces a pattern one to two inches wide that spans the entire length of the coil. This results in a wedge-shaped pattern that detects as deeply at the front of the coil as it does at the rear, deleting the need to overlap sweeps. Even with its large size, the PDD retains a high degree of sensitivity to small targets.

Field Test

I mounted the PDD on the working end of my GTI 2500 and initially performed a preliminary air test plus one more test. Although not conclusive, this test gives a fair idea of what you might expect from this coil in the real world. The test was performed in coins mode with the sensitivity cranked to the max. A half-dollar came in at 14-16 inches, a quarter at 12-plus inches, a dime, cent, and nickel at 10-12 inches.

A gold nugget test was conducted by placing a quarter-inch gold nugget into a small gold bottle and burying it at a measured six inches. With the 2500 set in all metal and the sensitivity cranked to the max, I scanned the target and got a strong signal at this depth and a weaker signal all the way out to eight to nine inches. On a three-sixteenth-diameter nugget I was able to get three to four inches. In the detector hell ground in my back yard, this was fairly impressive.

When the coil first arrived here in Oregon Mother Nature was in a state of terminal PMS and it was many days before I could get out, then hunting was sporadic to say the least. My first trip was to a large elementary school on the other side of town where I hunted a large soccer field that has always produced coins. Setting the 2500 in coins mode, I started scanning the edge of the field and coins started showing up right off the bat. The first coin was a quarter at eight inches. When the 2500 identified it as such, I quickly pinpointed the coin and removed it from its grave.

Pinpointing with this coil is extremely accurate but a little different. Although there is a decal in the center of the coil for pinpoint, there is no receiving coil in the PDD for pinpointing, so coin-sized targets are best pinpointed off the tip of the coil. Just center the target side-to-side, slide the coil straight back until the signal just stops. The target will be right at the center tip of the coil.

Continuing on my next target was a bottle cap. DD coils do not discriminate as well as concentric coils so you will catch bottle caps with this one. My next coin was a dime at six inches. I centered it, backed the coil up, and the dime was right at the tip of the coil.

Over a period of about two hours at this site I picked up about $3.50 in clad and some deep junk I purposely dug to simulate relics. The coil ran smoothly, very stable, identified within its limits, and picked up some deep objects, such as a small jar lid at well over a foot with signal to spare. It was far too muddy to dig many of these.

My next trip was to a park that is home to an old iron smelter built in 1867, and the ground around it is crummy with iron and slag. I wanted to see how this coil handled the iron and it performed quite well except over large deposits when it would just overload. I even managed to pick up three dimes and a quarter in this mess, at depths up to six and seven inches. Since the smelter is next to a big river I wandered down to the sandy beach where I found my share of bottle caps plus four dimes and a quarter at depths up to seven inches. Then as I was about to leave I got a solid signal next to the water's edge that read half at nearly ten inches. Anxiously digging into the damp sand I recovered a ragged 1977 Kennedy half at just below ten inches. It wasn't silver but still a half. The beach was too crowded with sun-seekers and kids to do extensive hunting that day but the PDD performed exceptionally well and the Kennedy half was a welcome reward.

Over the next few weeks I managed to slip out between rainstorms and hit several sites, picking up a variety of coins and trinkets, including a child's sterling silver ring in an old park that rang in at eight inches. This one item proved the sensitivity of the PDD to small jewelry and related items. My total coin count for this test came to a little over $13 plus trinkets.


For ring hunters, this coil is hot on gold rings. I conducted an air test on a large 14-carat gold wedding band and it was still beeping at over a foot from the coil. For all Garrett users who wish to find some of the goodies beyond the reach of the coil you have been using, and the ground where you hunt is your enemy, then the PDD should most certainly be your weapon of choice.

The non-imaging PDD with its large footprint is ideal for searching parks, schools, beaches, large grassy areas, and for prospecting. Heavily wooded and brushy areas may pose a problem but you should be able to maneuver it around most obstructions and find those deep goodies.

With its solid epoxy-filled open design the PDD is built like a tank for durability and is fully submersible. At a nickel shy of $180, with a two-year guarantee, it's a real bargain for punching through heavy mineralization and recovering those targets missed by other coils. The PDD fits The GTI, GTAx series, and the Treasure Ace 300.

For more info on this great new coil contact Garrett Metal Detectors at 1881 W. State St., Garland, Texas 75042-6797 or phone them at 1-800-527-4011 or 972-494-6151. You can also fax them at 972-494-1881, visit their web site at, or email them at salesatgarrett [dot] com. Don't forget to mention that you read about the Power DD coil in Lost Treasure.

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