Top 12 Metal Detectors

Whites Surfmaster PI Metal Detector Field Tests at Kellyco Metal Detectors

Reprinted with permission from Lost Treasures
From page 36 of the October 1993 issue of Lost Treasure magazine.
By Andy Sabisch

White's Electronics was one of the first companies to produce a fully-submersible metal detector called the Surfmaster TR back in the 1970s. In 1981 they released the PI- 1000, their first pulse type detector, which quickly became the "detector-of-choice" for shallow water hunters and divers around the world. Its pulse circuitry was able to ignore adverse ground conditions such as black sand and salt water while responding to metal objects at exceptional depths. Reports of "worked-out" sites producing literally thousands of silver coins and pieces of gold jewelry were received by the factory on almost a daily basis. Over the years, White's has continued to improve on the design and performance of their pulse circuit and their current line of waterproof detectors contains both the PI-3000 and the new Surfmaster P.I., as well as a detector featuring a VLF circuit -- the Surfmaster II.

FEATURES

The Surfmaster P.I. utilizes a pulse circuit which results in maximum detection depth under virtually all ground conditions. Unlike VLF or TR-type detectors which may require frequent adjustments when searching areas such as salt-water beaches or soil with rapidly changing mineral content, the Surfmaster P.I. automatically ignores these "ground effects" resulting in more time spent recovering targets and less time making complicated adjustments.

Unlike most other pulse detectors currently available, the Surfmaster P.I. features a form of discrimination that allows users to ignore certain types of non-ferrous targets such as tinfoil and pull tabs. This discrimination is accomplished through a circuit called "PULSE DELAY" which varies the signal transmission rate and is controlled by a knob on the front of the case.

Maximum target detection depth is achieved when the PULSE DELAY control is set at the minimum position; however, all metal objects will produce a signal. As the PULSE DELAY control is turned in the clockwise direction, specific nonferrous targets will be rejected; however, a noticeable loss of detection depth will occur. As with any detector, it is advisable to use as little discrimination as possible in order to avoid missing a deeply-buried target or a small piece of gold jewelry.

The electronics of Surfmaster P.I. are mounted inside of a case made of heavy-gauge acrylic plastic similar to that used on underwater cameras and other electronic devices used by divers. Two metal clamps hold the lid/O-ring assembly securely in place, and the case is certified leak proof to a depth of 30 feet.

There are currently two versions of the Surfmaster P.I. available with the only difference being in the search coil that comes with the unit. For those treasure hunters that plan on spending most of their time on dry land, the non-weighted 9.5 inch coil is recommended. Whit it does have a tendency to float when submerged, it is lighter in weight and more suited for extended searching on the beach. The weighted 9.5 inch coil is designed for divers as well as TH'ers that spend most of their time wading in shallow water. The weight of the entire detector with the buoyant coil is 4 pounds 8 ounces, and the weighted coil adds an additional 10 ounces. For those people that need the heavier loop but find the weight and overall balance of the detector to be uncomfortable for land use, there are two solutions. First, the control housing can be easily hip mounted by depressing a pair of spring clips and removing it from the shaft. The second option is to remove the control housing from its normal location in front of the hand grip and reinstall it on the section of the shaft between the arm cup and the grip. Spring clips are included for this purpose and it will greatly improve the "feel" of the unit - particularly when searching for extended periods of time.

The Surfmaster P.I.'s operation is controlled through two knobs located on the front of the control housing and an internal variable resistor. The knob labeled "PULSE DELAY" serves a dual function. It turns the unit on and varies the pulse rate of the signal as discussed previously. The knob next to it labeled "TUNER" also provides two functions. It is used to adjust the threshold signal heard through the headphones and, when turned fully counter clockwise, tests the strength of the batteries. The battery condition will be indicated by the volume of the tone produced when the knob is placed in BAT CHECK position. When the tone is barely audible, the batteries should be replaced. Releasing the two metal snaps and removing the lid of the control housing reveals the circuit board. There is an adjustment screw located on the lower left-hand corner of the circuit boardjust above the battery compartment which allows the user to adjust the volume of the signal heard through the headphone. It has sufficient adjustment range to provide the desired volume for both waders and divers alike. An interesting note in the manual states that due to the Surfmaster' s circuit design, increasing the volume has no affect on the life of the batteries which is unlike most other detectors.

Another feature that has been incorporated into the Surfmaster P.I.'s circuit is the Self Adjusting Threshold or S.A.T as it is commonly known. This feature shows that the engineers at the White's took the time to design a detector with the end-user in mind. Once the audio threshold has been adjusted for one's personnel preference, the S.A.T. circuitry will automatically maintain that setting even as the ground mineralization changes. By enabling treasure hunters to search from the dry sand to the wet sand and finally into the surf without requiring any adjustments to the detector, more time will be available to locate targets resulting in more "goodies" in your pouch at the end of the day.

The Surfmaster P.I. is powered by eight AA penlight batteries which are replaced by opening the control housing and removing the plastic holder. The detector comes equipped with standard carbon batteries; however, the manual recommends using high quality alkaline batteries for optimum operation. The carbon batteries supplied with the unit will result in 10 to 15 hours of use and alkalines will boost that time an additional 15 to 20 hours. An optional 10-cell Nicad rechargeable battery pack is available, however it will only last 10 hours between charges and the battery test feature will not provide you with an indication of the battery pack's strength.

A small packet containing silica gel is packed inside of the control housing and is designed to absorb any moisture that might find its way inside of the case. While it will not protect the circuitry from a major leak, it can remove the dampness introduced by a few drops of water or extremely humid air. The pack should be periodically dried out in accordance with the directions specified in the manual.

INITIAL IMPRESSIONS

After assembling the Surfmaster P.I. and reading over the instruction manual, I was interested in seeing how well it responded to various targets.

Laying out several items including a few gold and silver rings, coins, a pull tab, tin foil, and a rusted nail, I proceeded to air-test the unit with both the TUNER and PULSE DELAY controls at the preset marks. The first aspect that quickly became apparent was that the response to the various targets was remarkably similar to that of a standard VLF-type detector rather than the "oscillating" or "clicking" sound found on many pulse units. I also noticed that unlike previous pulse detectors, objects would produce a solid signal even when passed in front of the coil at a rapid rate.

On most pulse detectors the loop must be swept very slowly in order for a noticeable response to be obtained. This shortfall has been completely eliminated in the new Surfmaster P.I.

With the PULSE DELAY set at the minimum setting I was able to get repeatable signals on all of the targets at depths of up 7 inches. As I began to increase the pulse delay, I found that the tin foil was rejected while still responding to the larger gold rings. It should be noted that the PULSE DELAY control has no affect on the signal produced by ferrous targets such as nails, hair pins, screws, etc.

At the maximum position the pull tab gave only a broken signal; however, all of the gold rings were rejected and the overall detection depth was less than half of what it had been at the preset mark. As mentioned previously, one can see why very little discrimination, if any at all, should be used to ensure valuable targets are not overlooked.

Taking the Surfmaster P.I. out to my test garden, I received signals on most of the targets buried with the exception of a deeply buried dime and a pair of Civil War bullets at almost 9 inches. As with the air test, I found that by increasing the PULSE DELAY a significant loss of detection depth occurred and at the maximum setting, even some of the shallow targets would only produce an intermittent response.

Pinpointing was a little more difficult than with a conventional detector; however, by checking the target from several different directions and listening for the loudest audio signal, I was able to get within an inch or two of the target center.

The first site that I took the Surfmaster P.I. to was an older, well used beach located in central Alabama. This would be my first visit to the area; however, several fellow treasure hunters had told me that they had made some interesting finds there over the years.

Arriving at the beach I put on my wet suit, set the controls on the detector to the preset marks, and waded out from the shore. With the threshold signal just discernible, I began searching in about two feet of water. Almost immediately l received aloud signal, and after dumping a scoop of sand into the sifter, I picked up my first coin of the day - a clad quarter. It was soon apparent that no one had hunted this beach recently because clad coins were quite common. Over the next two and a half hours I recovered almost 30 clad coins and memorial pennies along with a number of pull tabs, bobby pins, and other pieces of trash so common to swimming sites. Despite my success I was a little surprised that I had not found any jewelry.

Hoping my "luck" would improve if I tried the deeper section of the beach, I headed out until the water was up to the middle of my chest. There were fewer signals in this area and it took several minutes before I located my first target. While attempting to recover the target, the desirability of the weighted search coil quickly became quite obvious to me. As I released the pressure I had been exerting on the rod of the detector, the loop floated towards the surface and the control housing, being heavier, sank towards the bottom. After struggling with the detector and long-handled scoop for several minutes, I found a way to work with the buoyant coil. Once I pinpointed the target and placed my foot next to the coil, I would move the coil to the side and gently place my other foot on top of it to keep it from floating to the surface. Another more durable solution would be to purchase a coil weight that clamps onto the detectors shaft from your local dealer and install it when searching in water any deeper than your waist (or buy a Surfmaster P.I. with a weighted loop initially).

Surprisingly, many of the signals that I received in the deeper water turned out to be pieces of tinfoil from cigarette packages. In order to avoid digging these pesky targets, I increased the PULSE DELAY control until they produced a "scratchy" signal and continued hunting. I realized that I would be sacrificing some detection depth and might miss some smaller pieces of gold jewelry; however, the number of good targets I would recover would increase by not wasting time on the foil. After nearly an hour hunting the deeper area, I headed into shore to see what I had recovered.

Dumping my sifter out on the grass, I picked out 13 coins, all modern, a set of car keys, and two rings -- unfortunately both of them were gold plated.

As I walked around in the sun trying to warm up, I looked down the length of the beach and saw a diving board at the end of the pier sticking out from shore. I felt fairly certain that the area underneath the diving board had not been worked previously so I pulled my SCUBA gear from the back of the truck and headed towards the pier. Shortening the Surfmaster P.I.'s shaft as much as possible, I put the regulator in my mouth and dropped to the bottom. As I approached the area near the diving board I received nearly a constant signal. Hoping that it meant a solid layer of coins and other valuables, I reached into the mud below the loop and immediately felt several beer and soda cans. Not willing to give up completely, I attempted to clear a small area and then work it with the Surfmaster.

After nearly 30 minutes of picking up cans and piling them on the edge of the pier I was ready to try searching the bottom. This time I was plagued by smaller pieces of trash such as tin foil and pull tabs so I increased the PULSE DELAY to maximum and rechecked the area. Despite the loss of detection depth caused by this adjustment, I was able to ignore nearly all of the non-ferrous trash and with the last 40 minutes of air in my tank, recovered 11 coins including a 1954 silver quarter and three wheat cents from the 1940s and 1950s. I found it difficult to maneuver the detector underwater due to the length of the rod; however, the factory indicated that the optional Divers Rod was designed to alleviate this concern.

The instruction manual states that the Surfmaster P.I. can be used for relic hunting "due to its inherent sensitivity to gold, copper-nickel alloys and lead." Since I spend a fair amount of time searching for Civil War relics from the Atlanta Campaign that was fought near my home, I decided to see how well it performed in this application.

One of the battle sites near Kennesaw Mountain contains extremely mineralized ground, and even the best detectors available have a difficult time handling these conditions. Hoping that the Surfmaster P.I. would be able to ignore the mineralization, I packed my equipment in the truck and drove over to the site.

Hiking up the hill to an old Confederate trench line, I set the PULSE DELAY at the preset mark and adjusted the TUNER until a faint threshold came through the headphones. After only a few sweeps I received a loud signal. Centering the coil over the target I began to remove several inches of dirt. When the detector indicated the target was out of the hole, I spread out the loose dirt and came up with a small piece of barbed wire that had been buried about 4 inches deep.

Over the next few minutes I recovered several more pieces of wire from the top edge of the trench and began to get somewhat frustrated. Walking about 30 feet further down the hill, I began searching again. Almost 20 minutes went by before I received my first signal. After several minutes of digging in the hard clay, I saw something white laying on the pile of dirt. Wiping it against my leg, I saw it was a dropped .58 caliber Minnie ball. Considering that it had been almost 5 inches deep, I was hoping that possible additional relics other treasure hunters had missed might still be in the area.

Carefully searching the immediate area produced three more Minnie balls and a small artillery shell fragment. Continuing down the hill Iran into more barbed wire and handfuls of rusted nails. Due to the inability of the Surfmaster P.I.'s circuit to ignore ferrous items I decided to call it a day and head back to the truck.

While I was not able to work this site as thoroughly as I would have liked due to the amount of trash present, the detector had ignored the mineralized ground which had caused problems for virtually all other detectors in the past. If there had been fewer iron objects in the ground the Surfmaster P.I. would have probably produced artifacts others had passed over.

SUMMARY

The Surfmaster P.I. has been designed to provide treasure hunters with a simple-to-use detector which is unaffected by adverse ground conditions. I found that once the threshold level was set, the detector operated without requiring any further adjustments. Precise pinpointing was somewhat difficult primarily due to the size of the search coil; however, since recovering targets from a beach or in the water is relatively easy, this should not be a major concern. Overall, the Surfmaster P.I. functioned well in the various sites I searched with it.

Since the Surfmaster P.I. will be used primarily on the beach, a coil cover is highly recommended to prevent damaging the coil. Another option worth buying if you plan on doing any diving with the detector is the Diver Rod Kit which allows the shaft to be shortened to a convenient length needed for one-hand operation.


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