Coiltek 15 Inch Wot Searchcoil
By Andy Sabisch
From Page 52
November, 2000 issue of Lost Treasure

Minelab is a brand of metal detectors that has only been around since the mid-1980s; however, in that short period of time they have developed a line of detectors with features found on no other brand. As with most of the detector companies, Minelabs focus on metal detector technology has left the door open for other companies to develop accessories to further enhance the performance of the detectors they build. Coiltek is one of those companies. Coiltek opened their doors in 1988 initially producing coils for Minelab itself. As Minelab grew and began to build their coils in-house, Coiltek started to design optional coils for the Minelab line that provided users with enhanced detection capabilities. Initially their efforts were focused on the line of gold detectors since much of the detecting in Australia was electronic prospecting. With the rise in popularity of the Sovereign and Excalibur for coin and relic hunting worldwide, Coiltek worked on developing a coil for those models as well. The result is the 15 inch Double-D coil affectionately called the Wonderful Orange Thing or WOT for short and can be used on either the Sovereign or Excalibur (with the use of a special waterproofing kit). Having been an avid Minelab user for more than 10 years, I was anxious to see how the WOT performed in the field.


The biggest difference between the WOT and the large coils available for other brands is the coil design itself. Most coils on the market today are concentric coils; i.e., two coils, one slightly smaller and placed inside the other. The coil sends out a cone-shaped pattern that gets smaller the deeper the signal penetrates. What this means is that at a depth of 7-8 inches, an 8 inch coil is only looking at a 2-3 inch area resulting in much unsearched ground. Unless you overlap each sweep by 50 percent or more, you will wind up missing many deeper targets. The coils used by Minelab on most of their detectors are Double-D coils; i.e., two coils in the shape of a large V that overlap in a narrow strip down the center of the coil. This results in a pattern that is only 1-2 inches wide but the entire length of the coil. It also detects as deeply at the front of the coil as it does at the back requiring no overlap to avoid missing deeply buried targets. By its inherent characteristics, the Double-D coil retains a high degree of sensitivity to smaller targets even with larger coil sizes something that does not happen with concentric coils.

Coiltek spent a considerable amount of time and money developing the WOT to ensure it would actually provide enhanced performance over what was currently on the market. Not wanting to simply re-package existing technology, they tested the new design in areas around the world. The final product is the WOT and it is touted as a coil for coin hunters, beach hunters, relic hunters and cache hunters.

The WOT is 15 inches in diameter; however, the open design and materials used in its construction make it extremely light for the size. Combine the coils light weight with the center mounting point, one can use the WOT for extended periods without being worn out.

There are no adjustments or re-calibrations required when installing the WOT on a Sovereign other than the slight adjustment you typically make on the digital meter. To install the WOT on an Excalibur requires that you cut the cable going between the control housing and the standard coil and then install a special connector provided by Coiltek. A waterproof cover completes the process and Coiltek assures you that no water will get into the connection. Based on feedback from people that have made the conversion, it works as advertised; however, realize that cutting the cable will void your warranty.

Field Test

The first site I took the Sovereign / WOT combination to was a Civil War skirmish site that was being cleared for a new development just north of Atlanta. The area had been hunted for more than 25 years and I knew that the relics that remained would more than likely be quite deep. Since the area was fairly trash-free, I opted to search in the All-Metal mode and check any signals in discriminate. Walking up a slope that had been recently cleared; I received a solid signal that checked good in Discriminate. Using a mattock, I started to dig in the hard red Georgia clay. I re-checked the hole several times and finally, at more than 10 inches, I saw a Williams Cleaner bullet partially exposed in the hole. Pleased with my initial success, I continued up towards the top of the hill where some trenches were still evident. On the way, I recovered four more bullets at similar depths. It was interesting to note that there were signs of recent digging by other relic hunters in the same area and they had obviously missed the bullets I had found. The trenches were a little more difficult to search than the open slope due to the size of the coil and the confined nature of the trenches.

After some trial-and-error, I found that standing in the middle of the trench and sweeping the coil along the sides parallel to the center worked the best. The deep leaf cover made it difficult to accurately determine the depth of targets I recovered but they ranged from 4 to more than 12 inches underneath the leaves themselves. In addition to several shotgun shells and other modern trash, I did find three more bullets and an infantry cast I button. On the way back to the truck I took a shortcut through the woods; however, I found that the thick undergrowth made it extremely difficult to sweep the WOT.

The next site I visited was an area on the south side of Atlanta where some of the Confederate trench works from the defense of the city still remained. Some of the area was part of a park and was covered with grass. This made searching with the larger WOT almost effortless compared to hunting in the heavy underbrush at the previous site I had been at. As with most sites here in the south, this one had been heavily hunted before but I was optimistic about the capabilities of the WOT in detecting some of the deeper targets that might still be present. Opting for the All-metal mode for maximum depth, I started searching along the tree line. Less than five minutes went by before I received a clear signal. It turned out to be a round musket ball at just under 10 inches. Nearby a .58 caliber bullet was recovered at nearly 12 inches. Over the next two hours I recovered 14 bullets including one carved into a dice piece. As a point of comparison, my hunting partner searching the same area with his Sovereign equipped with a 10 inch coil found 3 bullets. On several occasions he came over to check my signals and was unable to pick them up even at maximum sensitivity and using the All-Metal mode.

My job transferred me to central Pennsylvania and brought most of my detectors and accessories along with me including the WOT. I was interested to see how well it faired when used for coin hunting. There was one old abandoned school nearby that I along with dozens of other treasure hunters had searched many times over the years. I know that no place is ever truly worked out but a good day was one or two clad coins any more. I put the WOT on my Sovereign and decided to spend an hour or two at the old school. Starting out in All-Metal I was quite surprised at the number of signals that I was picking up. A check in Discriminate showed that they were mostly ferrous trash so I opted to use the discriminate mode as my search mode. I hunted this site several times over the next week and found 43 coins including 5 silver dimes and 12 wheats, a silver ring, token and other trinkets. Many had been deeper than I had ever found coins in this area before 8 inches or more!

I have talked with beach hunters on both the East and West coasts that have had phenomenal success with the WOT in areas where they were not finding anything with the 10 inch Minelab coils. Coins at depths approaching two feet in the wet salt sand and larger items such as watches or pendants even deeper. The one complaint that I did hear was that it was tiring digging that deep for targets I guess one could have worse problems!


If you own a Minelab Sovereign or Excalibur and you want to reach targets that are beyond the reach of the 800 or 1000 Minelab coils, then the Coiltek WOT is something you should seriously think about adding to your equipment arsenal. It provides a significant increase in detection depth and unlike larger concentric coils used on other brands, it does not loose any sensitivity to smaller targets with the increased depth. My experience as well as that of others I talked to showed that many targets the WOT detected were beyond the depth of standard coils.

The WOT is ideal for searching open areas such as grassy parks or sandy beaches. Wooded areas pose a challenge in terms of being able to sweep a large coil but in most cases, you should be able to work it around most obstructions!

The Coiltek WOT sells for $349 and comes with a one-year no-questions-asked warranty. An introductory special brings the cost down under $200 which makes this a real bargain in terms of the additional performance it provides. The model that fits on the Excalibur sells for $60 more.

For more information or to order a Coiltek coil for your Minelab metal detector, contact Profile Gold Prospecting Supply, Coilteks exclusive U.S. distributor for their entire line of searchcoils. You can reach Doc Lousignont by writing to 3740 S. Royal Crest Street, Las Vegas, NV 89119, calling (800) 477-3211 ext. 11 / 1-702-732-8000 ext. 11, faxing (702) 732-1572 or visiting their web site at h Be sure to mention that read about the Coiltek WOT in Lost Treasure!

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