User manual

22
Garrett Metal Detectors AT Max
™
International
23
GND BAL Button—Hold the SHIFT button for Automatic Ground
Balance or, for Manual Ground Balance, push and release SHIFT
and then use the (+) and (-) MAN. GND BAL buttons.
Detector performance can be negatively affected by ground
mineralization. The AT Max International can be ground balanced
either automatically or manually to cancel unwanted ground
signals and obtain maximum stability and target detection.
Note: Always locate an area of soil free of metal before
attempting to ground balance the detector.
The AT Max includes High Resolution Ground Balance, with
175 points of resolution, ranging from conductive soil, such as
saltwater beaches, to ferrous mineralized ground. During Ground
Ground Balance
Balance function, the words GND BAL appear on the display and
the ground balance value is indicated on the LCD.
Automatic Ground Balance: Press and hold the SHIFT button
while continually "bouncing" or "pumping" the searchcoil from 1
to 8 inches (2 to 20 cm) above the ground until there is a minimal
audio response from the ground. 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 to 75 are indicated
with whole numerals. Ground balance values from 75 to 99
represent hot ground, and at this point the AT Max utilizes High
Resolution Ground Balance. Beginning at 75, the ground balance
value begins increasing in quarter-point steps. This is represented
by a whole numeral and increasing quarter-steps of the upper bar
graph. (See illustration below.)
GND BAL Indicator
(only displays when in use)
GND BAL
Button
MAN. GND BAL
(must press SHIFT first)
GND BAL Setting
(only displays while in
Ground Balance Mode)
Ground Balance
Window Value
Ground Balance values above 75 increase in quarter-points of resolution. The
above illustration indicates a Ground Balance value of 87.5. Above the solid
numeral 87, each quarter-point of value is indicated by five blocks of pixels on
the upper scale.
Fractional Ground Balance
Setting (Setting = 93.5)