Garrett's Gta 1000 Ultra
By Andy Sabisch
From Page 8
March, 1991 issue of Lost Treasure
The Graphic Target Analyzer, or GTA 1000 Ultra, is the newest addition to the Garrett line of metal detectors and is truly unique in both design and performance.
The GTA 1000 is a full-featured computerized metal detector that offers virtually an unlimited number of operator-set program options, yet is simple enough to be used directly from the box by pressing only one button.
The first evident feature is the unique construction of the GTA 1000 which results in exceptional balance. The GTA is mounted on a modified S-shape rod and, with the standard 5" by 10" elliptical searchcoil, weighs only 3 pounds 8 ounces.
The GTA 1000 comes equipped with the new Garrett elliptical-design searchcoil which provides for excellent ground coverage while being able to locate valuable targets extremely close to trash targets. The loop is waterproof and the GTA can be submerged up to the control housing for shallow-water hunting or prospecting in streams.
The new padded-armrest design features a built-in detector stand which keeps the GTA 1000 upright when recovering a target.
The battery packs and the internal speaker are also incorporated into the armrest which helps improve the overall balance of the detector. The battery pack is removable and has a belt clip built-in which allows it to be hip-mounted which further reduces the weight of the GTA 1000 by nearly a pound. A coiled cord connects the battery pack to the armrest which allows for easy removal and replacement.
By using surface-mount circuit board technology, pressure-sensitive touch pads, and an LCD meter, the control housing has been reduced in size to only 4-1/2" wide, 3-1/2" high, and 2-1/2" deep. Nine touch pads, located on the face of the housing, control the operation of the GTA 1000.
The touch pads are POWER, which turns the detector on and off; SELECT, which allows change of any of the controls; <+> and <->, which are used to adjust the control selected; OPERATE, which returns the GTA 1000 to the search mode after all changes have been made; LAST MODE, which will switch the GTA between the last mode used and the current mode (i.e. from COINS to ALL METAL and back again); PINPOINT, which activates the electronic pinpointing and depth reading circuitry; and ACCEPT/ REJECT, which allows the user to define the targets to be accepted or rejected.
The GTA 1000 features 6 operating modes. Three have been set at the factory and are called the COINS, BEACH, and ALL-METAL modes. These have been calibrated to allow the treasure hunter to quickly change modes as needed with virtually no adjustment; however, any of the settings can be changed if desired. The other three modes are operator programmable. All of the functions on the detector can be adjusted and the settings will be retained in the operator-programmable modes even when the power is turned off.
The GTA 1000 allows the user to start hunting with virtually no instruction simply by pressing the POWER touch pad. The detector will be in the COINS mode and will automatically reject nails, tinfoil, most pull tabs, and screw caps while still locating nickels, most gold rings, and other coins. Changing the operating mode on any of the GTA's functions is extremely simple.
By pressing the SELECT touch pad, the display on the meter will change to the setup mode with its six choices. The current mode will be shown by a constant display while the other modes will be flashing. By using the <+> or <-> pads, you can select any of the modes to search in. Once the MODE is selected, if you continue to press the SELECT touch pad, you will be given the opportunity to change the detection depth (sensitivity), audio threshold, and audio tone, or select surface elimination, enhanced audio response, and the type of batteries being used. All of these features are operated with the <+> or <-> touch pad.
When all the desired changes have been made, press the OPERATE touch pad to begin searching. The GTA prevents the user from making an error by alerting with a rapid series of "beeps" if the wrong touch pad is pressed during this process.
The meter on the GTA 1000 provides a great deal of information. In the lower right comer of the meter, battery strength is continually indicated. When the batteries have 20 minutes of life remaining, the segments will begin to flash, warning the user to replace them.
There are two rows of 24 individual segments across the top of the meter, each having two functions. The lower row indicates what targets will be accepted or rejected based on if the segment is displayed or not. When using the pinpoint mode, the lower row will indicate the target depth in inches. The upper scale will identify the target when the searchcoil passes over an object; and, when in the pinpoint mode, will indicate signal strength to aid in locating the target before recovery. The meter will also display what options have been selected by the user.
The GTA 1000 incorporates some unique functions that need further discussion. The SURFACE ELIMINATION circuitry will ignore most targets within one inch of the surface when activated. This is useful when searching an area with lots of surface trash and potential for older coins beneath it.
By ignoring targets near the surface, a lower level of discrimination is needed which results in more good targets being located. It can also be used when you have a limited amount of time and want to ignore the modem coins near the surface while still locating the older coins in the area.
The AUDIO BOOST circuit will amplify and enhance extremely weak signals that are usually caused by very deep or small targets. In heavily-hunted sites, this feature will. allow those targets overlooked by most treasure hunters to be located.
The BATTERY TYPE circuit allows the user to identify whether ni-cad or standard alkaline batteries are being used which results in the GTA accurately displaying battery strength during operation.
Another feature of the GTA 1000 is the loop-recognition circuitry found on the Grand Master II CX and Master Hunter CX On most detectors, the target identification and coin-depth reading circuits have been calibrated for the standard searchcoil that comes with the unit. If larger or smaller coils are used, the accuracy of the readings becomes questionable. The GTA automatically senses the loop installed and provides accurate readings with any of the factory loops.
A headphone jack is located on the rear of the armrest assembly and will accept any standard 1/4-inch headphone plug.
The GTA 1000 is powered by 8 AA-penlight batteries, held in 2 battery packs located inside the armrest. The batteries can be replaced by opening the door at the rear of the armrest and sliding the packs out. There are no wires connecting the batteries to the detector, and there is only one way to reinstall. the packs, eliminating the possibility of damaging the circuitry. The alkaline batteries that came with the detector provided me with over 30 hours of use.
An optional ni-cad rechargeable battery system is available from the factory, and will. provide 10- 12 hours per charge. Important reminder: any customized programs that you have saved in the three user-programmable modes will be lost if the batteries are removed for longer than four minutes.
I unpacked and quickly assembled the GTA 1000. An important fact to remember is to ensure that the searchcoil cable is wrapped securely around the shaft to avoid any false signals which may be caused due to the high sensitivity of the unit.
The instruction manual is extremely detailed and is pocket size for quick reference in the field. The GTA 1000 also comes with a 25 -minute video tape which explains the controls and shows how to search with the detector. After reading through the manual and watching the video, I laid the detector on the table to air test its response to targets normally encountered in the field.
I turned the GTA 1000 on and selected the COINS mode of operation. Leaving all the controls at the factory-preset settings, I passed targets such as coins, jewelry, small relics, and trash past the searchcoil. The GTA 1000 produced clear repeatable signals at impressive distances on most of the targets and provided accurate target identification readings on the LCD meter. The nail, tinfoil, and pull tab produced no audio response; however, the meter did indicate what the target was.
I then took the GTA 1000 outside to my test garden to check response to targets ranging from 3-8 inches deep in the mineralized red clay. I checked each of the targets in the COINS mode with the controls at PRESET. The GTA 1000 detected each good target and provided a positive target ID reading, while rejecting the trash targets.
One of the gold rings produced a broken signal and registered near pull tab; however, since some gold rings appear electrically similar to pull tabs, it is nearly impossible for any detector to reject all pull tabs while still accepting all gold items.
Pressing SELECT and using the <+> touch pad to switch to the ALL METAL mode, I increased the- detection depth to 90% and repeated the test. The GTA 1000 was able to detect each of the targets, even with the loop held an inch or two off the ground, and provide accurate target identification with only one sweep over the target. Most importantly, the GTA did not produce any chattering or falsing due to the mineralization present, despite the high sensitivity setting.
I found that pinpointing with the GTA 1000 was very simple to accomplish. When a target is located, the searchcoil is moved slightly off of the target, and the PINPOINT touch pad is pressed and held. The searchcoil is then moved over the target, and the upper segment on the LCD meter is observed. When it reaches the farthest position, reading from right to left, the target will be directly below where the rod connects to the coil and the depth will be indicated by the lower segment.
I decided to see how the GTA 1000 performed while searching for coins in some of the local parks. At the first park, I selected the COINS mode and left all other functions at the factory-preset position except THRESHOLD, which I reduced since I was using headphones.
Near the swing set, I passed the searchcoil over several pull tabs laying on the ground and was pleased that the GTA did not produce any audio response. I received a solid signal that indicated DIME, and by pressing the PINPOINT touch pad, the meter showed that it was four-inches deep. Recovering a clad dime, I continued searching.
Over the next 10 minutes, I re covered a few more coins when I received a signal that indicated just below where zinc pennies had been reading. From three inches, I found a bottle cap. To ensure that I would not locate any more of these, I passed the coil over the cap, observed the meter indication, and pressed the REJECT touch pad. The corresponding segment on the lower scale disappeared, and the GTA no longer produced a response when the searchcoil was passed over the target.
I found that the elliptical searchcoil could be brought extremely close to the metal supports for the swings or climbing gym without receiving a signal. This allowed me to find several coins within an inch or two of the metal posts that probably would have been missed with a round coil.
Over the next hour, I was able to recover 32 coins. Most importantly, with the GTA in the COINS mode, I had recovered only four pieces of trash despite the large amount of trash that was in the ground.
Over the next few days I spent several hours in other parks and tried out more features of the GTA 1000. In one park, several soda cans had been run over by a mower, resulting in small pieces of scattered aluminum. In order to ignore these targets, I decided to use the SURFACE. ELIMINATION feature. By ignoring the targets in the first inch, all the aluminum slivers were ignored, and I was able to recover a number of coins below them.
Later, at a school yard dating back to the 1930s, I searched the grassy area behind the playground but received very few signals; therefore, I pressed the SELECT touch pad and turned on the AUDIO BOOST circuit to amplify the weaker signals. After several minutes with still no signal, I began to wonder if it was time to move one. Finally, near a large tree, I received a signal that read PENNY on the meter and indicated almost eight-inches deep in the PINPOINT mode; it turned out to be a 1936 wheat cent.
Over the next 30 minutes, I found 4 more wheat cents and a 1946 silver dime at similar depths, and all produced clear, repeatable signals. As I headed back to the area around the swing set, I easily turned off the AUDIO BOOST circuit, and continued to recover coins among the trash.
The next site I took the GTA 1000 to was the stamp-mill foundation from one of the old gold mines near my house. My wife and 1, as well as many other TH'ers, had searched this site previously; however, due to the mineralization and the amount of ferrous trash present, hunting was extremely difficult.
Due to the ferrous trash, I decided to search in the BEACH mode which would automatically ignore pieces of iron and tinfoil while responding to all other targets. I also pressed the SELECT touch pad, chose the ALL METAL mode, and pressed OPERATE. Then, by pressing the LAST MODE touch pad, I could easily switch between the BEACH and ALL-METAL modes to determine the size of a target, or check if multiple targets were present.
I returned to BEACH mode and began searching near the foundation. The mineralization caused some falsing at the preset sensitivity setting, so I reduced the sensitivity to 60% and continued searching. Near one of the doorways I received a signal that registered just above NICKEL, and indicated five-inches deep in the PINPOINT mode. After cutting a plug and removing the loose dirt, the detector indicated that the target was out of the hole. Carefully sifting through the dirt produced an 1898 V nickel in fair condition.
Filled with renewed enthusiasm, I continued to search. After 15 minutes, I received a signal that read below penny; however, it would not repeat. Turning 90 degrees, I swept the searchcoil over the area and this time received a repeatable signal.
I went to LAST MODE to check the area in ALL METAL and saw that there were several targets nearby, all reading as IRON. Quickly pinpointing the good target, I recovered an 1892 Indian head penny from 41/2 inches.
Over the next 45 minutes I found one more V nickel dated 1902 and two Indian head pennies dated 1894 and 1901 and, other than I shotgun shell casing and 4-.22 shells, had not recovered any trash targets. The ability to switch between the discriminate and all-metal modes at the touch of a button was extremely useful in determining target value.
A few days later we returned to the site. Rosanne used the GTA 1000; she selected the COINS mode, and left the sensitivity at 60 percent. Searching near the bottom of the foundation produced some non-repeatable signals; however, by using the ALL METAL and PINPOINT modes, she determined that they were being caused by large ferrous objects and concentrated smaller trash targets.
Along a narrow pathway she received a signal that bounced between QUARTER and HALF and occasionally would not repeat. Checking the area in - the ALL METAL mode indicated that there were several targets quite close together with most registering as iron. Turning slightly and rechecking the spot in the COINS mode, a repeatable signal was obtained; PINPOINT registered five inches.
After cutting a plug and moving some roots, she saw a silver coin near the bottom of the hole. Carefully brushing some dirt off revealed an 1876 Seated Liberty Half Dollar in extra fine condition. After admiring the coin, we agreed that it would be hard to match that find and decided to head home.
Our next site was the Central Alabama Artifact Society Treasure Hunt (this was Rosanne's first competition hunt). She selected the COINS mode and reduced the sensitivity to 50% to avoid interference from other detectors. During the silver dime hunt she was able to find as many targets as some of the "pro's" had found. In other hunts, she found several more silver coins, including a 1964 quarter at over five inches that had not been planted in the hunt.
Overall, the light weight of the GTA 1000, combined with the discrimination capabilities and lack of interference from nearby detectors allowed Rosanne to do quite well.
The Garrett GTA 1000 has been designed to be used successfully by either the novice or experienced treasure hunter in virtually any situation. The easily- adjustable functions combined with the programmable notch discrimination system allows the user to adjust the GTA to specific searching needs.
The factory offers a complete line of optional searchcoils including a 4-1/2-inch circular coil for high-trash areas, an 8-1/2-inch circular coil for general searching, a 12-1/2 inch circular coil for deeper targets or greater coverage with each sweep, and a YxT elliptical coil for trashy areas or prospecting in rocky sites.
If you're looking for a computerized detector that's extremely easy to use yet one you won't outgrow, check with your Garrett dealer for a close look at the new GTA 1000. For the name of your nearest dealer and a copy of the informative buyers guide, write: Garrett Electronics, 2814 National Dr., Garland, TX 75041-2397, or call (214) 278-6151 and mention that you read about it in Lost Treasure.