Metal Detector Field Test & Review - White’s Electronics Coinmaster GT
By Andy Sabisch
From Page 56
February, 2013 issue of Lost Treasure

There’s hardly anyone that has even a passing interest in metal detectors that has not heard of the White’s Electronics name as their reputation for producing quality metal detection equipment is legendary. 
Started by Ken White, Sr. and his wife, Olive, in 1950, Mr. White and a sole employee started out by hand-building one Geiger counter a day for people searching for uranium. 
Word of the quality of their equipment quickly spread and by the time the government stopped buying uranium 8 years later, Mr. White had 65 employees and the rest is history as they say. 
The Coinmaster line contained some of the most popular and productive detectors available throughout the 1960’s, 1970’s and 1980’s. 
The retired name has been resurrected with a new series that draws its pedigree from the Prism line, which helped many people learn about detecting and see what was waiting to be found just beneath the surface. 
The latest addition to the Coinmaster line is the Coinmaster GT, offering some surprising features for the price at which it is offered.

The Coinmaster GT comes well packed and is easily assembled. While it sports the Coinmaster name, it does not share the same design as the other Coinmaster models; i.e., the basic Coinmaster and the Coinmaster Pro. 
Due to the additional circuitry found on the GT, and the switch from two 9-volt batteries to 8 AA batteries, the battery pack is mounted under the arm rest, which while a tad heavier than the other models, provides perfect balance across the entire adjustment range of the shaft.
The GT weighs just over 3.5 pounds with the stock 9” concentric coil and battery pack. The combination of the AA battery pack and the low-draw circuitry provides for 25-30 hours of operation with alkaline batteries. Rechargeable batteries can be used with no impact on performance.
A comment I’ve made before when reviewing the Prism line is that the case is made of plastic rather than the legendary metal White’s housings, but from what I’ve seen and White’s has reported, it is as rugged as metal with less weight…nothing wrong, just different.
The GT offers two distinctive motion-based search modes – Discrimination and All-Metal.
An important point to note is that the visual target ID system – both the coarse grouping provided by the arrow beneath each of the 9 icons along the top of the screen, and the larger VDI number in the center of the screen (ranging from -95 to +95) providing more accurate target identification - is active in both search modes, which expands the GT’s versatility.
All adjustments are made using the 7 touchpads located beneath the LCD display on the face of the control housing. 
Showing thought for the end-user in the design phase, all of the touchpads can be accessed using the thumb of the hand holding the detector – many detectors require two-hand adjustments, which can be cumbersome at times and it’s nice to see that the GT is an exception to this.
The touchpads include ON/OFF, TONE ID, SENS(itivity), TRAC LOCK, BEACH, PP/ALLMETAL, and DISC(riminate) that provide the following functions:
ON/OFF: This serves a dual function – it turns the detector on, and if held, it activates a very useful backlight ideal for hunting in low or no light conditions such as beaches after the crowds leave, or areas where heat during daylight hours may be a determent to detecting
TONE ID: If you are in the motion discriminate mode, this touchpad allows you to activate an additional target ID circuit where each of the 9 distinct groups of targets shown above the LCD produce a different tone enabling you to identify targets based on their audio response.
If you prefer a single tone from all accepted targets, simply toggle this off. In the All Metal mode, selecting the Tone ID activates or deactivates a Voltage Controller Oscillator (VCO) audio circuit.
When active, the pitch and volume increases as the coil gets closer to the target, which helps pinpoint and separate targets in close proximity to one another.
SENS(itivity): As the name implies, this adjusts the sensitivity to metal objects as well as outside electrical interference and ground mineralization. Setting it as high as possible without the GT becoming unstable will result in maximum detection depth.
There are 8 distinct settings which are shown on the right side of the screen.
TRAC LOCK: The GT features a fully automatic ground balancing system which will continually monitor ground conditions and make any adjustments that might be called for.
If you find yourself in ground where mineralization changes frequently, contains traces of rusted iron, or you feel that the circuit is tracking too quickly and is causing detected targets to fade away, activating the TRAC LOCK function will prevent the GT from trying to make continual adjustments and can improve overall stability under certain conditions.
BEACH: If you hunt saltwater beaches or areas with high alkali content, such as the deserts of the Southwest, activating the BEACH circuit changes the range of the ground balance & tracking circuits to better handle these conditions. Simply press the touchpad, allow the GT to track the ground and start hunting
PP/ALL METAL: Pressing and releasing the touchpad will toggle between the motion Discriminate and motion All Metal search modes.
Pressing and holding it will activate the non-motion Pinpoint mode, and in this mode the display will change to indicate the target depth in 1/2” increments from 0” to 12.” 
NOTE: The GT actually has two depth indications – the small one on the left side of the screen reads out continuously when a target is detected and indicates in 2” increments from 0” to 10”+.  I
n pinpoint you get the larger indication in the center of the screen.
DISC(riminate): The GT has nine separate groups of targets which are shown as icons above the screen.  Incorporating notch discrimination, users can decide how to handle any of the groups simply by pressing the upper half of this touchpad to scroll through the groups and then accept or reject each one using the lower part of the touchpad.
Operating the Coinmaster GT is about as easy as it gets…simply turn it on, select the preferred search mode, adjust the desired level of discrimination & sensitivity, sweep the coil across the ground to set the ground balance for conditions present (or bob the coil up & down a few times), and start searching for a good target. 
The Coinmaster GT features a battery monitoring system which checks battery strength when the unit is turned on.
Good batteries will produce a high pitched tone while batteries nearing the end of their life produce a low tone. When they are almost exhausted, a LOW BATT icon appears on the screen along with a distinctive 3-beep alarm.

Field Test
As with any detector I am trying for the first time, I spent a little time checking the response to various targets – both good and bad – in an air test as well as in a test garden I added to the yard of a house I recently moved into.
My new house was built around 1915 and, while there is not a lot of yard that has not been disturbed or covered over, I was interested to see what the Coinmaster GT might turn up, as this would be my first time searching it since moving in. 
Rejecting the first two target groups (both being iron), I bumped the sensitivity up to 6 out of 8 and started hunting along the curb of the street. 
A few clad coins turned up from just under the surface to 3” deep or so, and the target ID as well as depth indication (both the continuous indication and the Pinpoint display) were dead on.
As I started my second pass I received a solid signal that registered as “55” and indicated a depth of 4 inches. 
Cutting a plug and checking with my probe I saw it was still in the hole.
Removing another few inches of soil, I saw something in the loose dirt and pulled an old child’s lead cannon free from where it had rested for many decades.
I was impressed with the GT’s response to the little cannon which had been between 6” and 7” deep. 
Finds such as this one mean more to me than a common coin as they are unique and one always wonders about the story behind how they wound up laying beneath the ground for so many years.
In case one questions the accuracy of the indicated target depth in this example, remember that the GT’s depth indication is based on a coin-sized object. 
Larger objects will tend to indicate a shallower depth than they actually are and the opposite will occur on targets smaller than coins; i.e., they will indicate that they are deeper than they actually are. 
Another 45 minutes searching the small side yard turned up more than I had expected based on its size and my “loot” included nine clad coins and memorial pennies, three Wheat cents, with the oldest being 1917, a 1936D Mercury dime, and a few gears that seem to have come from an old clock.
The Wheat cent was the deepest coin recovered and had been a solid 7” deep. The VCO option in the Pinpoint mode combined with the depth indication allowed me to quickly zero in and recover it...something that is a challenge on some detectors in the GT’s price range.
Not having the time between receipt of the detector and press-time for the magazine to visit my son and hunt some of the saltwater beaches around Charleston testing the Beach mode, I opted to take the Coinmaster GT to several local sites where ground conditions and trash content varied to see how it handled these challenges.
The next site I visited was a small park in the center of town that dated back to the late 1800’s. Based on the visibility of the park, I knew it had been hunted many times before, but as they say, it’s hard to get it all. 
Starting with the Discrimination set to reject the first three notches (iron and foil), I headed towards a pavilion on the far side of the park. Unfortunately, the ground was littered with pull-tabs and more were clearly just under the surface so additional discrimination was called for.
A few quick “clicks” on the DISC touchpad rejected the notch beneath the pull-tab icon and the Coinmaster GT went along ignoring those pesky targets.
Clad coins were fairly plentiful and I was surprised to find several in the 3” to 4” range, which indicated that the park might not have been hunted as thoroughly as I had initially suspected. 
Approaching one of the large oak trees towering over the playground area, I received a signal that indicated “70-71” on the VDI display and was clearly deeper than the other coins I had recovered so far. 
Cutting a plug – or at least attempting to do so thanks to a large root above the target – I worked to remove dirt from under the root. 
Finally retrieving it, I was happy to see it was a Wheat cent dated 1934.
It’s amazing the difference in the condition of recovered coins from different soils and the dark dirt in Illinois left coins in far better shape than the red clay surrounding my old house in the South had. 
I was able to recover one more Wheat cent – a 1956 – from the park, but a point that stood out was that I had recovered six nickels while still rejecting pull- tabs.
There is always the risk of losing a good target as more discrimination is applied; however, when time or patience is a factor, it’s good to see that the Coinmaster GT has the ability to accurately reject specific targets while not inadvertently rejecting those that one wants to retain.
Over the next few weeks I spent time hunting sites that were still in use as well some that had been abandoned for years.
In the older sites, which were littered with iron trash (nails, wire and the like), I found that hunting with the Tone ID turned off and adding minimal discrimination provided a “cleaner” signal and made it easier to discern the deeper signals.
Engaging the TRAC LOCK function also improved performance in that the detector was not continually trying to adjust for changes in the ground beneath the coil, which in most cases were the result of decaying iron trash. 
Remember that the target ID is displayed via a two-digit number in the main area of the screen as well as via the arrows beneath the icons along the top of the screen, so even with very little discrimination selected you can identify good targets amongst trash by the target ID values displayed.
In one area where a house had burned down years earlier, the smaller Double-D coil would have fared better than the stock 9” concentric coil, but by slowing down and working questionable signals from multiple directions; several “keepers” were recovered from this site.
Due to my work schedule and daylight savings time going away, I was forced to switch on the backlight at a few sites to finish up my hunts and found it worked perfectly – the display was very easy to read in the decreasing light.
Even with the use of the backlight, as I wrapped up the field test, the LOW BATTERY indication had not yet appeared.
Overall I found the Coinmaster GT easy to operate, lightweight and more importantly, a detector that allowed me to make some interesting recoveries at sites that other detectorists had visited before me.

White’s clearly recognized that there is a segment of active and would-be treasure hunters that want to go detecting yet don’t want to mortgage the house in the process of getting equipped. The Coinmaster GT offers this group a detector that is simple to operate yet provides features and performance that will find treasure even in sites that have been hunted by others at a price that will fit almost any budget.
Check out the new Coinmaster GT at your local White’s dealer and see if it has what you’ve been looking for. The White’s website contains more information as well as an informative video that covers many of the GT’s features and overall operation. The detector comes with the standard 2-year transferable warranty and retails for $399.95. Accessories for the GT including a 4”x6” Double-D search coil are available.
Contact the factory at 1011 Pleasant Valley Road, Sweet Home, OR 97386, (800) 547-6911, or visit their website at and be sure to mention you read about the latest addition to the White’s line in Lost Treasure Magazine.

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