Garrett AT Pro Owner's Manual page 23

• The detector will be less stable in shallow, breaking surf
where the searchcoil is in and out of the saltwater.
In this area the detector is encountering a constantly
changing environment produced by the surf, making it
difficult for the detector to stabilize.
To improve stability, negatively bias the ground
balance by several points. To do so, simply press
and release the Ground Balance button and
use the (-) NOTCH DISC pushbutton to manually reduce
the ground balance setting. For example, if the Ground
Balance number was 11, reduce the Ground
Balance number to 7 or 8. Introduce only
enough negative bias to achive sufficiently stable
operation. Reduce the detector's Sensitivity as needed.
Note: While some background chatter may remain, the
more definitive response of a target can be recognized.
• If necessary, notch out the first pixel under Foil. It is
important to note that by notching out this pixel,
detection of some small jewelry items will be reduced.
Tips for locating targets amongst terra cotta/hot rocks:
Magnetic minerals such as hot rocks and terra cotta can
mask the presence of good targets. In order to detect a good
target, first ground balance the AT Pro to the terra cotta or hot
rocks that are present. Be aware, however, that the combined
Target ID might be very low (e.g. a bronze coin and terra
cotta together may register between 10 and 15 on the Digital
Target ID). Therefore, Iron Discrimination levels must be
reduced in order to ensure detection of good targets covered
by the terra cotta. The Iron Audio feature can also be used
so that all targets above the point of discrimination produce
either a medium or high tone (i.e. "good" targets).
42 Garrett Metal Detectors
• Isolating adjacent targets. The narrow detection field
of the AT Pro's DD searchcoil allows better separation of
adjacent targets versus a similar size concentric searchcoil.
Use narrow swings of the searchcoil in trashy areas to isolate
good targets amongst the trash.
DD
Searchcoil
• Swing your searchcoil parallel to plow lines and the
water's edge. This will minimize the negative effects caused
by uneven ground in plowed 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.
Concentric
Searchcoil
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AT Pro™