Garrett Electronics Grand Master Ii
By Andy Sabisch
From Page 10
January, 1990 issue of Lost Treasure
The Garrett Grand Master II is the top of the Garrett line of metal detectors and is a greatly improved version of the original Grand Master that was introduced in 1988. Having used various Garrett detectors over the years with a great deal of success, I was looking forward to seeing how their newest addition performed in the field.
The Grand Master II is a full-featured metal detector that has been designed for both the novice as well as the experienced treasure hunter. The detector can be used directly from the box with almost no instruction, yet it does allow the user to create virtually an endless number of customized settings for specific applications.
The first features that are immediately apparent with the Grand Master II are its lightweight and excellent balance. The detector weighs a little more than 3-3/4 pounds with the batteries and the 81/2-inch search coil, and is extremely well balanced. As a matter of fact, when I removed the detector from the box, I thought that the factory had forgotten to include the batteries. The Grand Master breaks down easily into a compact package which is convenient for taking the detector on trips.
The controls on the Grand Master II look more complicated than they actually are. On the left side of the control housing, there are two knobs and four set of touch Pads.
The knobs are used for adjusting the discriminate settings in both the Ferrous and Non-Ferrous ranges and there are pre-set markings on both knobs which are designed for general coin hunting. The three sets of touch pads in the center of the side panel perform both primary and secondary functions.
The primary function is to allow you to control the Detection Depth (sensitivity), Audio Pitch, and Audio Threshold levels. The secondary function allows you to control the Ground Balance (manually), Volume, and Threshold Regulation (manual or automatic retuning).
The fourth set of touch pads is located at the rear of the panel and allows you to select one of three audio responses the detector will produce while in the discriminate mode. There is also a standard 1/4-inch headphone jack on the side panel with a plastic plug to keep dirt out when not using headphones.
The meter assembly which is located at the end of the handle also has five touch pads for operating the detector. The touch pads perform the following functions: ON- turns the detector on and allows the user to check the battery level while hunting. ALL METAL -places the Grand Master II into a non-motion, all-metal mode, and when held, activates the secondary functions of the touch pads on the side of the control housing, and engages the Fast Track ground-balancing circuitry; PINPOINT DEPTH- activates the depth reading circuitry and allows for precise non-motion pinpointing; DISC - places the detector into a ground-canceling, motion discrimination mode; and OFF - turns the detector off.
The meter itself serves several different functions. First, it indicates the strength of the batteries when the detector is turned on for approximately three seconds, and whenever the ON touch pad is pressed while operating. Second, it will indicate the approximate depth of coin-sized objects down to 12 inches. Third, it will indicate the probable ID of the target when operating in either the discriminate or all-metal mode. The final function is to provide the user a number of pieces of information on the upper 0 to 100 scale.
This scale can be used for determining signal intensity when in the pinpoint mode, or for detonating where each of the features adjusted by touch pads are set. For example, if either of the Detection Depth (sensitivity) touch pads on the control housing are pressed and held, the meter will indicate the present sensitivity level and then proceed to move in the direction desired based on the touch pad being pressed (<>, <->). This works with either of the three sets of touch pads on the control housing for both the primary and secondary functions.
A useful feature of the target I.D. circuitry is that if the Grand Master II is not entirely sure of the I.D. of the target detected, it will move the needle to the far left-hand side of the meter to the area marked Out of Target ID. Range. This will occur if the target is a piece of iron, the target is too deep or too small to identify, or if the target is too large or close to the surface and overloads the target I.D. circuitry.
As recommended in the manual, if the target appears to very weak when checking in the pinpoint mode, it is best to try and recover it as it might be a deep object, a coin on edge, or a small piece of jewelry. As the old adage says, If in doubt-dig.
Another valuable improvement in the Grand Master IIs circuitry is the automatic recognition of the size of the loop installed. On other detectors, the target I.D. and depth-reading functions are calibrated to the standard-size loop, and using either smaller or larger coins, the accuracy of these readings is reduced.
The Grand Master II He will automatically determine the size search coil installed and make the required internal adjustments to provide accurate target depth and I.D. readings regardless of the loop size used. If the two-box attachment, the Blood Hound, is installed, the Grand Master II will automatically sense this and function only in the all-metal mode.
The Grand Master II is powered by six C cell batteries which are located in a compartment at the rear of the control housing behind the handle. Inside this compartment, toward the front, are four small switches.
The center two are used to change the operating frequency of the detector slightly to eliminate the interference caused by electrical power lines, radio transmissions, or other Grand Master II operating nearby. These two switches offer four possible operating frequencies depending on the position they are placed in.
The outer two Switches are being reserved for a future use by the factory. Under normal use, alkaline batteries will provide about 25 to 30 hours of use. An optional ni-card rechargeable battery system is available that provides 15 to 20 hours of use per charge.
It is important to note that all custom settings made by the operator will be lost if the batteries are removed from the detector for more than four minutes. When using the ni-card system, the batteries are recharged in the detector to avoid losing any of the adjustments made.
The Grand Master II comes packed securely with an instruction manual small enough to put in your pocket and take out in the field for easy reference. During the assembly process, I found it easier to connect the search coil wire to the control housing due to the location of the housing connector. After spending some time reading over the instruction manual, I was ready to see how the Grand Master II responded to my test targets.
As stated in the manual, the detector can be used with very little practice in the Starter Phase. By setting the ferrous and non-ferrous discriminate controls to the preset marks and turning the detector on by pressing the On touch pad on the meter assembly, the detector is set up for most coin hunting situations.
When the Grand Master II his shipped from the factory, the sensitivity is set to 90 percent, the audio level will have a slight threshold sound, the audio frequency is set in the middle of the adjustment range and the audio response is set to standard. What this means is that if you make no adjustments other than set the discriminate controls to the preset marks, you will be searching with the detector set to the factory settings.
If you are using headphones and want to reduce the threshold sound, press and hold the audio threshold touch pad marked c-> until the sound level reaches the point that is desired. If you want to change the pitch of the audio response to targets, press and hold the audio pitch touchpad marked <+> to raise the pitch, or the touchpad marked <-> to lower the pitch. You may find that in some areas, the sensitivity level needs to be reduced to eliminate chattering or felting due to ground mineralization. This is done by pressing and holding the detection depth touchpad marked <-> and watching the meter. The needle on the meter will indicate the sensitivity level.
I began my testing by setting the discriminate controls to the preset marks and turning the unit on. The detector produced some chattering, so I reduced the Detection Depth to 75 percent to eliminate it With the Audio Response Depth set to Bell Tone, coins other than nickels produced the characteristic bell tone signal or as Garrett calls it, The Sound of Money.
I found that there was virtually no difference in the distance at which a target could be detected in any of the three audio response settings. With the controls at preset, the Grand Master II responded to most gold rings, while doing a good job rejecting pull-tabs.
After testing the response of the detector with a number of items, I took the Grand Master II out to my test garden to see how it responded to objects buried in the ground. The detector responded to all of the good targets buried, and rejected the trash items at impressive depths. The target I.D. was accurate as was the depth reading function in the pinpoint mode.
I tried searching in the all-metal mode, and found that in highly mineralized ground, either the Fact Track or the manual ground balance adjustment was required to maintain a steady threshold. Pressing and holding the all-metal touchpad on the meter assembly activate the Fact Track function. Sweeping the loop across the ground will automatically adjust the ground balance needed for the specific area. When a double tone is heard, release the touchpad, and the automatic Ground Track circuitry maintains the Grand Master II correctly ground balanced for the ground conditions that exist
If the Ground Track circuitry is unable to maintain the threshold due to extremely hot ground conditions that exist, or rapidly changing mineralization, the manual ground balance touchpads (secondary function on the Detection Depth touchpad) can be used to more precisely adjust for the mineralization present.
One important item that is not really covered in the manual is how to return all of the functions to the initial factory settings. If you have made a number of changes to the different controls such as Audio Level, Audio Pitch, Detection Depth, Volume, etc., or you have let someone else use the detector who has changed the settings you made to it, you might want to reset all the controls to the factory settings, and rebuild your customized program.
To do this, press and hold the all-metal touchpad on the meter assembly for five seconds. Then, press and hold the discriminate touchpad and release both touchpads at the same time. The Grand Master II will then be reset to the factory settings.
The first place I took the Grand Master II was to a nearby school built in the early 1940s that has been searched by nearly every treasure hunter in a 25-mile radius. I had recovered some nice older coins from here, but both the quantity and quality had dropped off in recent months. The number of previous hunters coupled with high mineralization and large iron objects in the schoolyard would provide a good test of the capabilities of the Grand Master II.
I walked around to the back of the school and turned the detector on. I set the discriminate controls to preset, reduced the Audio Threshold to result in silent operation, and set the Detection Depth to 80 percent. After a few sweeps, I needed to reduce the Detection Depth to 70 percent due to the falsing caused by the ground conditions, the Grand Master ran completely quiet at this point.
The first target produced a solid audio response and indicated penny on the meter. Switching to the Pinpoint mode and centering the target, the depth was shown at five inches. At about five inches, I recovered a 1944 wheat penny. As I got closer to the school building, I began to detect a number of screw caps from soda bottles. While the meter was able to I.D. them correctly, I decided to increase the non-ferrous discriminate control to eliminate them. After making this slight adjustment, I did not dig any more screw caps during my time at the school.
I then received a fairly strong signal that would not provide a positive target I.D., and when checking the signal in the all-metal mode, it appeared to be two targets very close to each other. Upon removing a plug, I found a large wad of tinfoil at about three inches. Not sure if this was the only signal, I checked the hole, and this time the meter locked onto "DIME."
At 5 112-inches deep, and less than one inch from the tinfoil, I recovered a 1936 mercury dime in excellent condition. After several hours, I decided to stop and look over my finds. Despite the number of hunters that had been there before me, I had still been able to recover over 60 coins including a number of older wheat cents, nickels, and the silver dime.
My old treasure hunting partner, Jim Harrick, had come down for the weekend from New Jersey, and wanted to try searching for Civil War relics. Since I live near Kennesaw Mountain and Atlanta, there were a number of sites available for us to hunt. One site that had been extremely productive in the past was being developed, so we decided to hunt it one last time before it was built over.
I proceeded into the last small stand of trees at the edge of the construction site and immediately saw a number of holes left by previous relic hunters. Setting the ferrous discriminate control to 15 to reject small pieces of iron and the nonferrous control fully counter-clockwise (disabling the upper discriminate range), the Detection Depth at 80 percent and the audio response to Standard, I began to search in the layer of leaves and branches.
After a few minutes, I received a strong signal that indicated ZINC PENNY on the meter. Pressing the Pin Point touchpad, I easily centered the target and read the depth at seven inches. From around that, I recovered a nice .69 caliber minnie ball which is fairly uncommon from this area.
As I continued to search on the small wooded area, I continued to find both dropped fired bullets at depths ranging froth four to nine inches deep. Despite a great deal of small iron nails and pieces of barbed wire, the Grand Master II was not falsing or responding to the trash items.
After an hour or so, I walked out to the area that had been cleared to try hunting in the all-metal mode. Due to the highly mineralized ground, I decided to use the Fast Track function to maintain a steady threshold tone. The Grand Master II functioned very well in this mode, and by using the meter to visually discriminate out the iron objects, I was able to recover another six minnie balls and a broken eagle button at depths of up to eight inches. After two hours, I had found 17 bullets and the button in an area that had been hunted extensively for quite some time.
On the way home, we decided to stop at an old abandoned house on the outskirts of a small town. The house had been built in the late 1800s and the yard was quite overgrown. I set the ferrous discriminate control at preset and the non-ferrous control fully counter-clockwise anticipating a lack of trash items such as pull-tabs and screw caps.
With the Detection Depth still at 80 percent, I began searching the front yard of the house. Near the path leading to the porch, I received a signal that indicated Penny on the meter. Checking the depth in the pinpoint mode showed the depth to be about eight inches.
After several minutes of trying to recover the target from under a large root, I found a 1927 wheat penny. After recovering several other coins in the area of the porch, I proceeded to the side yard. About halfway through this area, I received a signal that read in the quarter area of the meter, but did not lock when sweeping the coil over the target in different directions.
Checking the depth of the target showed it to be four inches deep, yet it appeared to be larger than a coin-sized object. After digging down four or five inches, the signal was still in the hole. At nine inches I recovered a toy cap gun in working condition. The size of the target had made it appear to be more shallow than it really was, but this is common among all target I.D. depth reading detectors-that are calibrated for coin-sized objects.
After two hours of searching at this site in 95-degree weather, I was ready to call it a day and headed home. In addition to the toy cap gun, I had found a number of old coins, a few clad coins including a 1967 half dollar, two old keys, and some metal cars from the 1950s.
I continued to use the Grand Master II, at various nearby sites for both coin and relic hunting and, in all cases, the detector functioned well providing me with a number of valuable and interesting finds.
The Grand Master II approved to be an excellent detector for all types of treasure hunting. I found it extremely easy to use to adjust for specific situations. The meter is easy to read and provides the user with a great deal of useful information.
The Grand Master II has a number of optional search coils available. With the sensitivity of the standard 8 1(2-inch coil, I would recommend the optional 4112-inch coil for searching areas that have a great deal of trash targets. The smaller coil would allow for more accurate target I.D. readings and less chattering caused by trash near the surface.
The optional 12 112-inch coil is ideally suited for relic hunting or searching for deep, older coins in areas that may been heavily worked in the past. The Depth Multiplier attachment easily converts the Grand Master II into a deep-seeking, two-box type detector for cache hunting or searching for larger relics while ignoring smaller targets such as nails or individual coins.
If you are looking for a full-feature, target ID detector that works well in all areas of treasure hunting, you need to take a look at the new Grand Master II before you buy your next metal detector. For the name of your nearest dealer, write the factory at Garrett Electronics, 2814 National Drive, Garland, TX 75401-2397 or call them at (214)278-6151. 75401-2397 or call them at (214)278-6151.