FIELD TEST

Lost Treasure Field Test Report Tesoro Clean Sweep Search Coil
By Andy Sabisch
From Page 24
April, 2004 issue of Lost Treasure

Since its inception, Tesoro Electronics has produced more optional search coils for their detectors than any other metal detector manufacturer. Jack Gifford, Tesoros founder, recognized the value in offering customers a wide range of search coils to handle all applications and this philosophy has been continued to the current line of equipment.

My family has used many of Tesoros detectors over the years along with most of the optional coils; however, my only exposure to the Clean Sweep coil had been a brief use on my Tiger Shark in an underwater search for a lost Rolex watch in some 50 of murky water (definitely a story for another day).

Details

Tesoro currently offers 10 different search coils for their line of detectors in both concentric and wide scan designs. The engineers at Tesoro designed the Clean Sweep coil using Wide Scan technology for two main reasons. First, it provides the same detection depth over the entire length of the coil providing excellent ground coverage with each sweep.

Secondly, Wide Scan coils are much less affected by ground mineralization, allowing them to be used in even highly mineralized areas without the falsing and chattering typically experienced when using a concentric coil.

The Clean Sweep measures 18 inches long by 3.5 inches wide and weighs in at 1.8 pounds. Dont think that makes the detector unwieldy, as it feels much almost feather-light when actually using it in the field based on the way it mounts. Hunting for hours should not be a problem for anyone using a Tesoro detector / Clean Sweep coil combination.

Wide Scan coils (or Double-D coils as they are also called) provide treasure hunters with an entirely different electronic field than the Concentric coil which is found on most detectors on the market today.

A Concentric coil is constructed with two circular windings shaped somewhat like donuts with one being mounted inside of the other. The detection field acts somewhat cone-shaped, i.e., the perceived detection field tapers as it goes away from the coil.

On a typical 8 concentric the actual area being searched at say 6 or 7 may only be an area 4 in diameter. As a result, if each sweep with a concentric coil is not overlapped by at least 50%, a fair amount of deeper targets will not be within the electronic field sent out from the coil. That is one of the leading reasons why there are still keepers in areas that have been heavily hunted for years.

Wide Scan coils on the other hand are made with two windings of the same size that are mounted in such a way that they overlap in the center. On a round wide scan coil, each winding is shaped like a D (hence the Double-D moniker). On a coil such as the Clean Sweep, each winding is rectangular in shape. By overlapping the windings in the center of the coil, the coil is able to detect targets along the entire centerline of the coil at maximum detection depth. This eliminates the need to overlap each sweep to ensure targets are not overlooked.

When you look at the Clean Sweep coils dimensions, it is easy to see the advantage it provides in being able to scan an 18-wide swath with every sweep. The detection depth is somewhat between what the round 4 and 7 coils provide, so while the Clean Sweep is not the coil to use if you are looking for coins on edge at 10, it excels in covering large areas in a short period of time where targets are not overly deep such as parks, schools, playgrounds and beaches.

Another positive feature of the Clean Sweep coil is the ease in which targets can be pinpointed. Since a target anywhere under the center of the coil will produce a signal of equal strength, one may initially wonder how to pinpoint a target.

Simply wiggle the coil from side-to-side just enough to generate a signal and slowly push the coil away from you. As soon as the signal disappears, the target will be directly beneath the back edge of the coil. With a little practice you will pinpoint targets with accuracy that will surprise you using a coil as large as the Clean Sweep.

One other interesting quirk that I found in doing some testing before taking the coil in the field came to light when I put it on my DeLeon. This model has a meter that provides target ID and depth indication. While the target ID was accurate, the depth reading for signals registered almost double what the reading was when the stock concentric coil was used.

For example, a quarter buried 5 inches in the ground registered 8 inches with the Clean Sweep coil. Not really a surprise since coil size does affect depth readings; i.e., a smaller coil results in readings deeper than the target actually is buried. Just a point to be aware of and another reason why a test garden is so important when trying out new equipment or honing your skills on your current gear.

Field Test

The timing was perfect for this report as the Clean Sweep arrived a few days before my family and I headed down to Charleston, South Carolina to spend some time with relatives for the Christmas holidays.

Getting up on the first day revealed sunny skies with temperatures heading for the high 60s--perfect detecting weather considering it was the end of December. Having brought along three different Tesoros to try the Clean Sweep with, a Silver uMax, an Eldorado and a DeLeon, we packed up our gear and headed for one of the local beaches.

While the weather was picture-perfect, it had been a while since the beaches were packed with bathers, so we knew that pickings might be a bit slim but one never knows what might turn up. We arrived at the first beach about two hours before low tide, ideal as far as being able to hunt the beach as the water receded.

My wife Rosanne wanted to do some hunting and after seeing how light the Silver uMax/Clean Sweep combination was compared to two other water detectors we had with us, she got the chance to use it first.

Setting the Sensitivity at 10 and the Discriminate between IRON and FOIL to ensure any small gold jewelry was not rejected, we started out near a large rock breakwater. As she started hunting in the wet sand area, I warned her to expect a good deal of chatter from the salt and black sand on this beach, based on past experience with VLF detectors (and concentric coils).

She responded that it was running completely silent which prompted me to walk over to see for myself. The ability of a Wide Scan coil to hunt without adverse effects of mineralization was readily apparent; this was the first time I had been able to hunt the wet sand on the Carolina beaches with a VLF detector without having to significantly reduce the sensitivity setting.

Several of the targets she detected were recovered from the 5 to 7 range, about the same as where I was recovering targets using a detector designed for the salt water.

We used the Clean Sweep with all three Tesoros, on several beaches surrounding Charleston and found the ability to hunt into the wet sand without much adjustment of the Sensitivity control being required was consistent among all three units. The DeLeon provided accurate target ID on signals even as waves washed over the coil and pinpointing with all three was extremely accurate.

On the last day at the beach we tried the Silver uMax/Clean Sweep in the All-Metal mode and found that a noticeable increase in detection depth was achieved. The way we hunted was to search in All-Metal and then check any signals in Discriminate. If the initial signal was faint (indicating a deep or small target) and no response was heard in the Discriminate mode, we scraped some sand away and rechecked the area. If the target were a deeper keeper, a positive signal would be heard. This technique allowed us to find some targets down close to 9, quite impressive for the Clean Sweep coil!

Arriving back in the Charlotte area, I took the Clean Sweep along with the Silver uMax and DeLeon to several local schools and parks to see how it performed when coin hunting. Many of them had large playground areas surrounded with bark or wood chips. This is an ideal location to find coins and other goodies since they disappear as soon as they are lost. Although I hit these areas on a regular basis to keep up my pinpointing skills, they are continually replenished with new items being lost.

I found that I was able to hunt them in a fraction of the time I usually spent using an 8 round coil and several of the coins that I recovered came from the bottom of the wood chip layer which told me that I was not missing any targets using the Clean Sweep coil. Even some of the wide open grassy areas that most detectorists tend to ignore were a snap to hunt with the Clean Sweep and with the increased area I could cover with each sweep. I was able to recover more targets per hour at sites I hunted on a regular basis than I had before with standard coils.

Summary

The Clean Sweep coil offers Tesoro users with a unique choice not afforded to users of most other detectors. If you are looking for a coil that offers exceptional ground coverage with each swing and surprising detection depth, the Clean Sweep definitely deserves a closer look.

I found that the Tesoro Silver uMax with the stock 8 concentric and the Clean Sweep coils offered an unbeatable combination in terms of performance and versatility at a price that fits anyones budget. If you already own a Tesoro detector, the Clean Sweep coil may just turn into your primary coil for most of your hunting.

The Clean Sweep coil sells for $189 and comes complete with a coil cover and a lower pole to make switching coils a breeze. Call the factory at (800) 528-3352, or write them at 715 White Spar Road. Prescott, AZ 86303.

Visit their web site at http://www.tesoro.com, for more information on the Clean Sweep or to obtain the latest copy of their informative Metal Detector Information booklet. Be sure to mention you read about the Clean Sweep coil in Lost Treasure!

Lost Treasure Field Test Report Tesoro Clean Sweep Search Coil


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