Garrett Metal Detectors Gtax 400
By Reg Sniff
From Page 14
May, 2001 issue of Lost Treasure

Founded in 1964, Garret Metal Detectors, the manufacturer of the GTAx 400, is one of the oldest metal detector companies. Besides this model, Garrett also produces one of the largest selections of detectors for treasure hunters as well as a wide variation for police and security purposes.
Designed primarily for the coinhunter, the GTAx 400 is best described as an economical motion detector equipped with target ID, notch discrimination, and sensitivity adjustment capability. Unlike some of the more expensive models, the GTAx 400 does not have all the features, such as a pinpoint mode, target depth readout, or multiple programming modes.
That is not to say that this detector doesnt have extra features, because it does. The first and foremost is the target ID feature. Equipped with the fundamental GTA (Graphic Target Analyzer) design, the GTAx 400, like other GTA detectors, has an LCD screen that divides the full detectable spectrum into 17 distinct divisions. Each division, or more commonly called segment bar, can be individually selected to accept or reject a target.
In basic terms, this means the GTAx 400 with target ID will allow the owner to see all metal targets, and both see and hear selected targets. More importantly, the detector allows the operator to select what targets they will hear and what ones will be ignored.
To select a target to be heard, one has to accept or turn on a segment corresponding to the target. To ignore an item, one merely deletes the corresponding segment bar. When a target is passed over that falls in the accepted range, the detector will respond audibly and the corresponding segment will be displayed. This feature, for the benefit of any new readers, is called notch discrimination.
Powered by 8 AA batteries (supplied) and equipped with an eight and one-half inch crossfire searchcoil, the GTAx 400 is well balanced, reasonably light and most of all, easy to use.
Assembly of the GTAx 400, like other GTAx models is quick and easy. Also, like other models, Garrett provides a brief Video that gives an excellent overview of the detector features and proper operational techniques. Personally, I strongly recommended that both new and experienced owners take time to watch the video, taking note of the proper sweep mode as well as the detector adjustments.
The GTAx 400 has five touchpad controls that are used to turn on and/or adjust the instrument. To turn on this detector, one merely presses the large ONE TOUCH touchpad and you are ready to hunt. Pressing the same pad again, will turn the instrument off. Initial setup of this instrument is the typical coin-hunting mode, where items such as iron objects and pull-tabs are rejected.
Getting Started
My personal preferences are a little different from the factory settings, so once I turned the detector on, I elected to adjust the discrimination settings. To do this, all I had to do was press the SET DISC pad, move the flashing cursor using the -" or the + touchpads to the segment I wanted to change, and then press the SET DISC pad again. Each time the SET DISC pad was pressed, the corresponding bar below the flashing bar would change state. Once finished I could wait for a few seconds for the program to reset to the hunt mode or I could quickly double tap the SET DEPTH pad.
I also elected to adjust the depth capabilities. Again, this was also a simple matter. To set the sensitivity or depth capabilities, I pressed the SET DEPTH pad and the present depth adjustment or capability would be indicated on the upper set of bars. Increasing or decreasing the depth capabilities or sensitivity was accomplished by pressing either the + or - pad. Once the depth adjustments were made, I had to press the SET DEPTH pad again to reset to the hunt mode.
Before going any farther, I would like to mention that once changes are made, they are stored in memory and remain when the detector is turned off and back on. This is a nice feature that allows a person to change locations without having to readjust the detector every time.
A person can reset the detector back to the original factory setting by pressing and holding the ONE TOUCH, on/off touch pad for several seconds or until you hear a beep.
Initial testing
Initial testing began at my home where I normally begin testing a new detector, over targets I have buried. Target depths range between three and six and a half inches.
Initial testing showed the target ID was very accurate on surface and shallow coins, and was respectably accurate on very deep targets. The signal from one deep dime was intermittent and read higher than normal, but this has been the norm on all other previous field tests. Overall depth capabilities were exceptional for an economical detector.
One feature lacking on this detector is a pinpoint mode, so, for a person like me who regularly uses this mode to center over a target and determine the target size, the GTAx 400 made it a little more difficult to pinpoint a target for digging. Pinpointing is done by xing the target with the search coil and mentally noting the location of the response. As for size of a target, I did find that I could distinguish a fairly large target by the longer response time.
In The Field
The GTAx 400 accompanied me to some rather strange places for testing. One such location was a site where we were looking for metal arrowheads. Although, very rare they have been found in an area about 40 miles from my home.
At this site, I found I could hunt at maximum sensitivity with no chatter and almost no false signals. What few false signals I did get, I finally determined, came from the vibration of wiring going to the searchcoil (my fault). I had the wiring a little too loose.
Hunting in the all-metal mode (all segments turned on), I didnt find any arrowheads (nobody did), but did find several pieces of metal including a few fence staples and small pieces of wire. The wire, like nails would usually give me a double beep when passed over from different directions.
The next location was also a failure as far as finding anything of value. It was the site of an old rodeo grounds abandoned in the 1920s. Unfortunately, the grass cover was extremely tall making it somewhere between difficult and impossible to get close to the ground.
At this site, I adjusted the detector to reject iron objects and accept all non-ferrous targets. I did manage to find a couple of strange items that I have not quite figured out, but no coins as hoped. Again, it was not the detectors fault.
The next strange location was in Arizona where I had planned to hunt for gold nuggets and meteorites for a week. Unfortunately, the trip was cut short and I didnt get to spend as much time as I wanted to try the GTAx 400.
While there, I did determine that this detector would not reliably detect the type of meteorite found at this location. This would be considered to be normal since the detector is set to accept metals and ignore hotrocks, and the type of meteorites found at this site responded like a hotrock.
As for gold targets, I tested the detector and found it could detect a small nugget, a little larger than a BB. Unfortunately, I didnt find any gold with the GTAx 400, but did find a few small pieces of lead. (I didnt find any gold with a gold machine either).
While searching for the elusive gold nuggets, I set the detector to accept all targets, knowing from experience that gold can respond about any way it wants.
During this testing, I did wish the stems of detector were a little longer. A tall person has to search very close to their feet.
Back home, I put the GTAx 400 through the tests it was primarily designed for, hunting for coins. My searches included the more common sites such as parks and yards.
My normal search mode was to accept all non-ferrous objects and reject only iron objects. The sensitivity was usually set at or near maximum, depending on the amount of interference nearby.
When I had finished I had found a very large pile of change, most of which were new coins. I did find a few wheatbacks to add to my collection. During my searches I recovered coin -sized targets from surface depth to depths ranging somewhere between 6 and 7 inches. Not bad for a detector in this price range.
The GTAx 400 is a very solid economical Target ID detector that has excellent depth for the price. Overall this detector is very quiet, and, as mentioned before, the target ID was respectably accurate. Simply stated, this detector goes on my recommended list of economical detectors.
For more information about the GTAx 400 or any of the Garrett detectors, one can contact Garrett at: Garrett Metal Detectors, 1881 W. State St., Garland TX 75042, phone 1-800-627-4011, web site: www.

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