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20 Garrett Metal Detectors

AT Max

™ 

21

Use the (+) or (–) SENSITIVITY buttons to step through the eight (8) 
levels. Use increased sensitivity when searching for very small or 
very deep targets. Use lower sensitivity levels when the detector 
is behaving erratically (due to excessive metallic trash, highly 
mineralized soils, electrical interference or the presence of other 
metal detectors) and the erratic operation cannot be resolved 
with ground balance, discrimination or by changing frequency.

Sensitivity

Sensitivity 

Button

Sensitivity 

Indicator

Audio Threshold Adjustment

Threshold is the constant background “hum” that is added to the 
target response. Press a Threshold button once to display the 
current setting. Press the (+) or (–) Threshold buttons again to select 
from 33 levels, ranging from -9 up to +23.
  Positive Threshold values add an audible background hum to 
the target response (i.e. positive audio bias), while negative values 
subtract audio from the target response (i.e. negative audio bias). 
A Threshold of zero adds no audio bias.
  Select a Threshold setting based on personal preference.  
However, to maximize the ability to hear faint signals, it is 
recommended to operate with a faint, yet barely audible 
threshold (i.e. faint positive audio bias). The louder the 
surrounding environment, the higher you may need to set the 
Threshold. Conversely, there may be times you wish to operate 
with a negative or silent threshold, for example, in order to reduce 
detector chatter, etc.
  Headphones are also highly recommended to maximize the 
ability to hear faint signals, particularly in noisy environments.

Threshold 

Buttons

Threshold Setting 

(only displays during 

Threshold adjustment)

Summary of Contents for AT Max

Page 1: ...ll Metal Mode Audio Characteristics 14 Discrimination Mode Audio Characteristics 15 Tone ID in Discrimination Modes 16 Proportional Audio Characteristics 17 Notch Discrimination 18 Sensitivity 20 AudioThreshold Adjustment 21 Ground Balance 22 Iron Discrimination 26 Iron Audio 28 Z LynkWireless Operation 32 BenchTests 34 HuntingTips 37 Pinpointing 41 Underwater Operation 45 Troubleshooting Guide 46...

Page 2: ...me pg 11 Sensitivity Direct press or keys to increase or decrease sensitivity level pg 20 Manual Ground Balance Press Shift Button then use or keys to change ground balance setting pg 22 Audio Threshold Direct press or keys to change level of background sound pg 21 Mode Indicator pg 12 Battery Level Indicator pg 47 Digital Target ID Also shows settings during adjustments Sensitivity Setting pg 20 ...

Page 3: ...d Factory default mode is Coins 3 0Adjust settings Adjust Sensitivity Threshold Volume or Discrimination settings if desired 4 0Begin scanning Lower the searchcoil to approximately 1 inch above the ground and scan the coil left and right at approximately 3 ft second The coil must be in motion for target detection but can remain stationary during Pinpoint Components Searchcoil Camlock Lower Stem Up...

Page 4: ...amlock by turning it right clockwise while holding the upper and lower stem assembly in front of you as shown below Extend lower stem and press mounting washers firmly into place Connect searchcoil to stem as shown and hand tighten wing nut Loosen upper camlock depress the spring clip in the S stem containing control housing and insert the S stem through the upper camlock collar into the upper ste...

Page 5: ...n then push the LIGHT button to switch the LCD backlight on or off Use the backlight in low light situations for improved visibility of the screen Adjust lower stem to comfortable length and hand tighten the camlocks Wrap cable snugly around the stem with the first turn of the cable over the stem Insert coil connector into the 4 pin connector of the control box by lining up connector pins Press fi...

Page 6: ... the maximum loudness of target sounds press the Shift button and then use the or VOL ADJUST buttons to set to your preference Note that the AT Max s volume adjustments only affects the maximum audio produced by a large signal and does not affect the audio level or sensitivity of faint signals i e Volume is a limiter and not a gain control thereby preserving maximum detection of faint signals To e...

Page 7: ...ects every type of metal All 12 discrimination pixels are switched on and High Res Iron Discrim is set to 0 zero indicating that no metals targets have been notched out eliminated Use this mode to find all metal items or when the material of the desired object is unknown Switch to the Zero Disc Mode to aid in locating a target when its signal is inconsistent Such signals could mean a trash target ...

Page 8: ... All Metal detector in that its Iron Discrimination and Iron Audio features can be used to hear if detected targets are ferrous as indicated by a low tone Iron Discrimination levels can only be adjusted in the ALL METAL Mode if the Iron Audio feature is on note these changes will not be retained when the detector is switched off See Iron Audio section pages 28 31 Gold prospectors and many relic hu...

Page 9: ...Example A Adjacent targets can often produce a single strong signal with many metal detectors The fast recovery of the AT Max however will provide two peaks of audio response to these adjacent coins These multiple audio responses provide the experienced user with more target information This fast recovery time helps the AT Max operator to separate adjacent targets The proportional audio response w...

Page 10: ...next time this item is encountered it will not produce an audible signal Tip Notch Discrimination can also be used to find specific metal items For example if an earring has been lost scan the matching earring in ZERO DISC mode and note its Target ID cursor Then press SHIFT and use the NOTCH DISC and ELIM buttons to switch off all the pixels except the one for the earring and an additional pixel o...

Page 11: ...buttons again to select from 33 levels ranging from 9 up to 23 Positive Threshold values add an audible background hum to the target response i e positive audio bias while negative values subtract audio from the target response i e negative audio bias A Threshold of zero adds no audio bias Select a Threshold setting based on personal preference However to maximize the ability to hear faint signals...

Page 12: ...Then release the button and begin hunting The ground balance value will have been indicated on the LCD A low ground balance value indicates conductive soil such as saltwater beaches high ground balance values indicate ferrous soil As the detector is being ground balanced the ground setting value can be observed where the Digital Target ID number would normally display Ground balance values from 0 ...

Page 13: ...ite ferrous oxide minerals black sands hot rocks terra cotta 60 80 Moderately mineralized soils red clay brown clay iron bearing clay minerals etc 20 60 Likely an iron object 0 20 Highly conductive non ferrous minerals such as saltwater Automatic Ground Balance Window Mineralized ground is often a mixture or matrix of different soils rocks and pockets of concentrated mineralization each possibly r...

Page 14: ...using the IRON DISC button In Illustration 2 the same iron nail is laying above a gold coin Since the Iron Discrimination level is now set to 24 the nail by itself would not be detected however the two objects nail and gold coin have a combined conductivity of more than 24 Therefore the gold coin is detected due to the combined conductivity being higher than that of the discriminated target nail a...

Page 15: ...ing tricked into digging an undesired target Iron Audio helps the operator identify flat iron objects such as bottle caps that would otherwise appear to be good targets With the use of Iron Audio discriminated iron targets normally silent will produce a Low Tone ID Using Iron Audio an iron nail Iron Audio Iron Audio is ON IRON AUDIO Button produces several fast low tones as the searchcoil passes o...

Page 16: ...produce a distinctive response of Low High Low as compared to the coin s response of only High tone Coin IRON AUDIO ON In All Metal Mode with this example iron targets below 35 are now heard with flanking low tones and targets above 35 produce a clean medium tone Mid Tone Low Tone Iron Audio Use in ALL METAL Mode In the ALL METAL Mode all metallic targets encountered by the AT Max are normally ide...

Page 17: ...Oncepaired iftheheadphone receiverisswitchedofformoved out of range the AT Max will search and attempt to reconnect to the receiver for 30 seconds indicated by a flashing icon If the connection is not reestablished during this time the AT Max will switch off its wireless transmitter It will be necessary to switch the AT Max off and then on again to initiate a new 30 second search To un pair forget...

Page 18: ...across the searchcoil again to verify that it has been eliminated If not raise the Iron Discrimination setting a little higher until the iron target no longer produces an audible response The factory preset Iron Discrimination level of 35 in COINS Mode will eliminate most iron nails from detection without adjustment Iron Audio bench test Next remain in ZERO Mode with your Iron Discrimination level...

Page 19: ...to the COINS Mode set IRON DISC to 35 and switch off the Iron Audio feature Pass the bottle cap across the coil again and notice the subtle breaks and inconsistencies of the target response indicating it might be good or made of iron Pass a non ferrous target such as a coin or gold ring across the coil and note its clean tone in comparison to that of the bottle cap Remaining in COINS Mode with IRO...

Page 20: ...d see pages 22 25 Saltwater beaches typically Ground Balance between 0 and 20 If necessary reduce Sensitivity until signals become stable Swing the searchcoil flat and at a constant height Do not bounce the coil or lift the coil at end of swings Swing the searchcoil parallel to the water s edge The detector will be less stable in shallow breaking surf where the searchcoil is in and out of the salt...

Page 21: ...d fields and varying amounts of moisture near the water Do not swing the searchcoil perpendicular to plow lines and the water s edge as this may produce abrupt changes in ground response that can reduce the detector s performance Pinpointing Accurate pinpointing enables fast recovery with the smallest hole possible To use Pinpoint Position the searchcoil to the side of the target s suspected locat...

Page 22: ...l side to side to center the target the point where the strongest audio response is heard and the maximum signal strength is displayed on the LCD Then pull the coil slowly toward you see Image A while noting the target signal DD tip pinpointing technique PULL COIL TOWARD YOU Indicates target position Image A Image B Once the target signal drops off both audibly and on the LCD meter shallow targets...

Page 23: ...or and narrow its detection field Continue moving the searchcoil toward the target to find its central peak response If needed repeat the retune process to further narrow the target s response A quality hand held pinpointer such as Garrett s Pro Pointer AT is a recommended accessory item to speed the target recovery process and to aid in locating secondary targets The AT Max can be submerged in wa...

Page 24: ...e other undesirable targets You may also use the ZERO mode which detects all metal targets to ensure desired targets are present Target ID Cursor bounces If your Target ID Cursor bounces erratically chances are you ve found a trash target However a Target ID Cursor may bounce if a good target such as a coin is not parallel to the searchcoil e g on edge It may also bounce if there is one or multipl...

Page 25: ...detector observe these precautions Never trespass or hunt on private property without permission National and state parks monuments and military zones etc are absolutely off limits Avoid areas where pipelines or electric lines may be buried If found do not disturb and notify proper authorities Use reasonable caution in digging any target particularly if you are uncertain of the conditions If you a...

Page 26: ...n and then the Warranty Support menu for more details AT Max Warranty and Service This device complies with part 15 of the FCC Rules Operation is subject to the following two conditions 1 This device may not cause harmful interference and 2 this device must accept any interference received including interference that may cause undesired operation Changes or modifications not expressly approved by ...

Page 27: ...ils fully submersible Garrett headphones Garrett Pro Pointer pinpointing detectors Z Lynk Wireless Receiver kits and a wide selection of books on treasure hunting are available from your dealer or by calling Garrett s factory at 1 800 527 4011 AT Max ACCESSORIES To see Garrett s complete collection of metal detector accessories and books please visit www garrett com and view products within our Sp...

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