Lock; Salt; Summary; Gain Control - Whites MXT PRO Owner's Manual

Chapter  MXT Pro Controls
Salt water beaches for example or alkali desert regions.
The Ground setting will not track into the nonferrous metal
region. The Salt setting will. The MXT Pro ground rejection
system is capable, in both the Ground
and the Salt settings, of considering some iron a ground
mineral. If operating in a known salt area, salt water
beaches for example, it is not necessary to balance in the
Ground TRAC setting. Simply select the Salt TRAC setting
and proceed to pump the search coil over the ground to
be searched. The Salt setting will balance and then track
to changes identically to the Ground setting only with an
extended range, well into the conductive target area.
TRAC Summary- The Ground TRAC setting is
recommended for most searching conditions.
Lock is used to hold a ground rejection setting that is first
established in the Ground or Salt TRAC positions. Lock is
recommended for areas that cause detector instability due to
spotty extreme ground peculiarities such as a lot of decom-
posing man made iron or random but regular high mineral
pockets or rocks in a low mineral base.
Salt provides extended ground rejection range to compen-
sate for conductive salt/alkali conditions. The Salt setting
can ground cancel extreme enough to reduce sensitivity to
low conducting metals, metals that appear low on the VDI
scale. The Ground TRAC setting will not balance nor track
into the nonferrous metal region. Despite this draw back the
Salt setting still provides improved overall performance while
operating in the salt/alkali ground condition.
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Gain Control/ON-OFF
With the GAIN control, you turn the instrument On/Off and
select the signal strength. You might expect increased signal
strength to always find more at greater depths. However,
high ground mineralization will mask good targets. It is
therefore necessary to adjust GAIN to give you the maxi-
mum allowable signal strength without masking targets or
overloading the circuit and at the same time allowing you to
operate the detector with a constant faint threshold hum so
that faint signals (deep or small targets) can be detected.

GAIN Control

The MXT Pro will indicate when ground mineralization is too
high for the current GAIN control setting. When the display
indicates, "OVERLOAD-REDUCE GAIN/LIFT LOOP" along
with an audible "squawk" reduce the GAIN till the overload
warning ceases.
On occasion, while searching, you might sweep the search
coil over a very large or very shallow target. The mes-
sage on the LCD display will read "OVERLOAD-REDUCE
GAIN/LIFT LOOP" only when the search coil is over
an isolated spot on the ground. Sweep the search coil
a little higher over the area and note the display and audio
indications to check for a real metal target. The MXT Pro self
corrects after the message and you can continue to search
as normal.
Again, OVERLOAD over a large area indicates Gain is too
high for the ground minerals. Overload over an isolated area