Garrett At 4 Beach Hunter
By Jack Reid
From Page 20
June, 1989 issue of Lost Treasure

The new Garrett AT4 Beach Hunter is an improved version of the AT3 Beach Hunter which I field tested for Lost Treasure (November 1987) at the time it was introduced. But there are a number of significant differences and performance is defi-nitely better, although my experi-ence with the AT3 was much more then satisfactory. Others have even used it with really spectacular re-sults.
The AT4 I field tested was sent to me directly from the factory. As-sembly was fast and easy and re-quired no tools. I simply followed the steps contained in the accompa-nying 21-page booklet. There were only two steps worth mentioning.
One is that packed with the detec-tor were two small rubber washers; these have to be inserted in the grooves on the inside of the stem connector ears, which are a part of the top of the search coil.
The other is that the coil cable must be wrapped around the stem and secured with two spring clips supplied with the detector to prevent false signals from a dangling cable. Some such arrangement is common to just about all detectors being manufactured today because of their increased sensitivity.
With the AT4 there should be three to four feet of slack cable at the upper end to reach the control box when body mounted, which is the detectors only search configuration.
When seen disassembled in the shipping carton, the AT4 seemed almost identical to the AT3 Beach Hunter. But once Id put it together and had a chance to read the instruc-tion book, I found some notable dif-ferences. Since the older Beach Hunter was such a departure from Garretts other detectors, a compari-son is worth mentioning.
Both stems are S-type with an armrest and a pistol grip handle, but the lower end of the AT4 stem is all fiberglass reducing the possibil-ity of false signals. When adjusted to a comfortable searching length for me (Im about 6), there is about a footless of exposed metal stem than on the older instrument.
The lower end of the AT3s stem was held in place entirely by a slip nut at the bottom of the upper sec-tion of the stem. This has been re-placed by snap locks and a double row of holes drilled in the upper section. While this is, no doubt, a more Stable way of doing it and the slip nut may have been a problem for some people, it never was for me, neither in the surf nor in tall grass.
Moreover, Ive seen the AT3 Beach Hunter successfully used in competitive Shootouts, where the detector is whipped back and forth frantically for as many as 45 minutes at a stretch, with pauses only to dig targets.
At first glance, the control boxes of both detectors seemed identical with the exception of the cosmetic change; the cover of the AT4s box is yellow while the AT3s is black. In fact, the position of the control knobs and their calibrations are the same for both instruments, as is the location and construction of the watertight, PINPOINT button. But there, similarity ends.
The coil connector at the back end of the box, which formerly had a permanently mounted, watertight connector has been changed to ac-cept a polarized watertight plug with a cap screw.
The same is true of the earphone outlet, which is in the same position as before, but now it also serves as an inlet for the charger, either 100 volts supplied with the AT4 or a 12-volt optional unit, to pump up the detectors ni-cads. These are the only batteries used thus avoiding the chance of compro-mising watertight integrity each time batteries had to be changed, every 30 or so hours of op-eration.
Gone also are the internal adjust-ments for threshold level and for fresh-water and land or saltwater pinpoint-ing. The bottom line is that the AT4 Beach Hunters control box is not intended to be opened for an in-definite period of time.
Ni-cads are good for about 20 ours of searching per charge and can be recharged up to 1,000 times, which adds up to years of use before the case has to be opened to replace them. The latches on each side of the control box have plastic inserts to prevent accidental opening, and the warranty is voided if they are re-moved. Although the control box is watertight and will resist pressure up to six feet, it is not made for diving or other deep-water use.
The control box is equipped with belt loops and a stout web belt with a clasp buckle is supplied with the detector. There is ample length for the control box to be worn hip mounted or to hang it from ones neck, which allows the detector to be used in somewhat deeper water without the control box being con-tinuously submerged. There is no provision to attach the control box to the stem.
Garretts new Crossfire search- coil, which is standard on the detec-tor, is both larger than its former standard loop (8 112 in diameter vs. 7 112) and lighter. So, while the nominal weight of the instrument is four pounds, three ounces, the swing weight (stem and coil) is feather light, being less than two pounds because it is always used in body mount.
Although both the control box and the coil are watertight, Garrett recommends washing them off with fresh water after theyve been in contact with salt water. Disassem-bling and rinsing the stem with fresh water is also suggested after use at a saltwater beach to get rid of sand and saltspray residue. This, in fact, makes sense with any detector to protect the snap locks.
The AT4 Beach Hunter is sup-plied with Garrett Model 16000 mono/stereo earphones rather than the watertight ones which were stan-dard on the AT3. The advantage is that they have individual volume controls on each phone while the watertight ones, which are available as an option, dont.
Improvements that arent visible lie in new electronics (the transmit frequency has been upped from 5.0 to 6.5 IUjz) which, combined with the new coil, have produced a more sensitive and deeper-seeking detec-tor and, at the same time, one less affected by salt mineralization and magnetic black sand. Garrett claims about a 30 percent increase in depth and sensitivity and, judging from my experience, this is just about right.
All of the controls are grouped in a panel at the upper end of the con-trol box. These consist of a com-bined Off/On switch and sensitivity control, a Non-Ferrous Trash Elimi-nation knob, a ferrous Trash Elimi-nation knob and a Pinpoint button. They are all water-tight and the knobshafts are sufficiently stiff to prevent accidental
Ground bal-ancing is built in, so there are no controls for this purpose. A watertight re-ceptacle for the earphones is also located on the control panel. This
doubles as the connection for the battery charger. Charging is done with the detector turned off, although the instruction book doesnt men-tion this.
The Beach Hunter is turned on by turning the Sensitivity knob clock-wise. This tests the batteries and the audio system at the same time. Three beeps mean strong batteries; two indicate that they are weakening but still adequate; one beep means Its time to recharge.
There is no speaker, which would be incompatible with a watertight control box. All the audio goes through the earphones. I didnt miss the speaker at all with either detec-tor. The sound of breaking surf will effectively mask weak beeps, even on a relatively calm day.
On top of that, using a speaker on a beach can always be counted onto attract a clutch of kibitzers, who quickly put an end to effective searching. Ive seen this happen even on a chilly beach early on a Monday. I dont know where they come from, but they materialize from nowhere seemingly as if by magic.
The AT4 Beach Hunter offers two operational modes: Search and Pin-point. The search mode is a ground-balanced, motion mode with notch discrimination. Pinpoint is all met-als, non-motion. The ferrous range elimination and non-ferrous range elimination knobs are used to set the discrimination program. The scales of each are marked with arrows to indicate suggested starting positions, as is the scale of the sensitivity control.
The intent of the AT4s discrimi-nation system is to be able to make probable target identification by audio, much in the way that a meter does it visually. When all three controls are at their suggested set-tings, iron nails, foil, small bottle caps and the like, will have little effect on the audio except as broken beeps. Nickels and small rings pro-duce a definite beep. The notch,
where the audio decreases or even drops out completely, is pulltabs.
All other U.S. corns, large rings and, unfortunately, large aluminum screwcaps, produce a distinctive belitone beep, which Garrett calls, coin alert The notch can be stretched to include the screwcaps by turning the Non-Ferrous Range Elim. knob clockwise, but its at the risk of losing pennies and/or dimes.
Working with AT4 in my test garden, I was able to arrive at a combination of discriminator set-ting and swing rate where the bottle caps no longer produced a really good coin alert, although they didnt drop out entirely. During my field test, where I dug everything, the indications were that I would have saved digging about half the bottle caps without losing any coins, just by audio identification.
The AT4 Beach Hunter is shifted to the pinpoint mode by pressing and holding the pinpoint button. There is a sharp increase is threshold hum when the target is directly under the marked center of the coil. The earli-est way to use it is to X the target. This proved adequate, even in places where digging had to be done very carefully. But on the beach, I was usually able to retrieve the target quickly with a scoop without pin-pointing.
The first place I took the AT4 was to a popular salt-water beach early on a Monday morning, where a Mend and I took turns searching with the detector. The beach has a lot of magnetic black sand, and Ive never been able to search it at full sensitiv-ity with any detector.
So I started out with the depth control fully clockwise and worked back from there until I no longer had false signals at the end of each swing. Turning it back about one-quarter of the way back from Max proved to be right for that part of the beach less correction than experience there with other detectors had led me to expect.
My discrimination setting turned out to just about right. We were able to predict bottle caps before we dug them about half the time without deteriorating the Coin Alert beep.
At one point, we got four distinct Coin Alerts close together on one sweep. It sounded like someone playing chimes and was repeated exactly when I swept the coil back.
The first scoopful of sand brought up three clad dimes and the second scoop, sure enough, a fourth dime all so close together that they must have been dropped at the same time. It was no great bonanza, but atribute to the accuracy of the AT4 Beach
Hunter nonetheless.
We found numerous other clad coins and a few items of junk jew-elry, mostly earrings. Mingled with these were three significant items.
One was a kitchen knife with a four- inch, serrated stainless steel blade. It gave a good, solid beep but despite its size didnt ring the Coin Alert, just the way it shouldnt have.
The others were both pennies. One was a 1980 in what would have been at least American Numismatic Association MS-65 (Choice Uncirculated) condition, except for a heavy red discoloration from years of contact with the acidity in the sand.
So it is reasonable to believe that the coin had been underground since its year of minting.
The other penny was a l937S that was so corroded that it took an 8X lupe to make out the date. Both were so deep that it took several scoops to bring them up.
This was in a popular picnic area that has been searched by many treas-ure hunters with many kinds of de-tectors. In fact, I had searched ex-actly the same place over a year ago as part of my field test of the AT3 Beach Hunter. I might have simply missed one coin, but not both.
This made me believe Garretts claim that the AT4 Beach Hunter has more sensitivity and depth than the AT3. I cant vouch for how well the other beachcombers were doing with their detectors, but those coins must have been swept over at least dozens of times without being de-tected.
If all a beachcomber is going to do is search picnic areas well away form the surf, a watertight control box is of value mainly because it. will keep blowing sand out. There are lots of coins, costume jewelry and often items of real value to be found there. But the real goodies are more likely to be recovered from out in the surf.
It takes considerable force to dis-lodge a large ring or bracelet, but wave action, possibly helped along by the slippery residue of suntan lotion, is often enough to do it.
On top of this, a person frolicking in the surf is probably not aware of the loss until its too late to recover it. Then theres the undertow formed by each wave gravitating back to the sea after it has broken on the beach. It will carry objects out into the water to the point where the wave loses velocity and objects fall to the bottom, usually a few feet out into the surf.
Its much like roaring mountain streams carrying gold nuggets down river and depositing them on the bottom in calmer water. This means searching out in the surf at least knee deep and exposing the control box to damage from salt spray, or even worse, a total submergencewhich usually means at least a big repair bill for a conventional detector.
Ive accidentally submerged the AT3 Beach Hunter several times and the AT4, which has even better watertight integrity, once without any problems resulting. I was care-ful to wash off the control boxes thoroughly with fresh water as soon afterward as possible.
Ive had my best luck in the surf with both detectors when the dis-crimination controls were fully counterclockwise, producing a mo-tion, all metal mode. Theres not much in the way of the usual junk out there but there are a lot of wrecks, some very old, and who known what kind of artifacts will be washed up, particularly after a storm?
Ive found a few of them search-ing the surf, all ferrous metal, all badly corroded, some to the point of being unidentifiable, and none of any real value, but theres always that next time.
Ive done better with jewelry and rings. Here again, searching in all metals is good insurance against losing any of the smaller targets, particularly plated ones. One find was a mans ring with a small lapis stone. It was definitely homemade and seemed to have been fashioned from some other object. It was dis-colored from long immersion, but there was no corrosion.
The material appears to be Ger-man silver, which is neither Ger-man nor silver. Its an alloy of cop-per, zinc and nickel and was first used in Britain in the 19th century, mainly for medical equipment.
The ring gave off a strong Coin Alert in All Metals, but a later air check showed that it would have been considerably weaker had the discriminator controls been set at the initial settings mark. It began to deteriorate notably with the Non-Ferrous Eliminator set clockwise even as far as Screwtop.
My experience with the AT4 in the surf revealed the only weakness I found in the detector, one that can be corrected easily. The non-metal-lic knurled nuts supplied as mount-ing fittings are too small to be suffi-ciently tightened by hand for use in the surf.
They were fine for use ashore, even in tall grass, but the coil is so light and large that the bottom currents tended to flip it up so that it was no longer parallel to the bottom, and I was continuously using one foot to maintain adjustment. The solution is to change them to wing nuts, as used on the AT3 Beach Hunter, so that theres more leverage for tighten-ing.
Other than this one minor and easily correctable deficiency, I found the AT4 Beach Hunter to be a highly satisfactory detector. Its a very worthy successor to the AT3, which I thought was a great detector, par-ticularly since l watched Jesse Black-shire of Memphis, Tenn., use one to win the $5,000 first prize at the Lost Treasure Classic last June, although it wasnt designed as a competition shooter.
Its price of $649.95 is a very moderate increase over the cost of the AT3, and since it offers better all-around performance and water-tight integrity, I think its well worth
it. For more information, contact Garrett Electronics, 2814 National Dr., Garland, Tx 75O41-2397.

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