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2. + and -
a. In Discrimination mode, + and - change the level of discrimination (target
rejection)
b. In All-Metal mode,
+ and - provide a manual override to the Ground Balance
Setting.
The goal of Ground Balancing is to eliminate the sound as the searchcoil is being
pumped over the ground. In some soils, the sound is not completely eliminated.
After balancing to ground with GG some users may want to further adjust the
ground balance point manually.
To manually adjust ground balance:
1. Operate in ALL-METAL mode.
2. Pump searchcoil up and down over the ground as in the GG procedure.
3. Press
+ or
-
while pumping
If the ground balance adjustment is incorrect, there will be a difference in the
sound as the searchcoil is either moving toward or away from the ground. It
sounds like you are either
pulling the sound out of the ground, or pushing the
sound into the ground.
•If the sound is louder as you raise the searchcoil, increase the ground
balance setting.
•If the sound is louder as you lower the searchcoil, reduce the ground balance
setting.
NOTE: Experienced users often prefer to adjust the ground balance to get a weak
but audible response when lowering the searchcoil. This is called
adjusting for
positive response.
Positive and Negative Response
The purpose of ground balancing is to adjust the metal detector to ignore ground
minerals. If the setting is incorrect, ground minerals will give either a
positive or a
negative response, depending on which direction the adjustment is off.
POSITIVE RESPONSE
If the G.B. setting is too high a number, the response of minerals will be positive.
This means that when the searchcoil is lowered to the ground in PinPoint or All
Metals mode, the sound will get louder as the searchcoil approaches the ground.
The sound will grow quieter as the searchcoil is raised. What, if anything, you will
hear in Discrimination mode depends on the discrimination setting.
When searching in an All Metals mode, if ground balance is properly set to cancel
the ground, and you sweep over a
positive hot rock, the rock will give a “zip”
sound similar to that of a metal object.
NEGATIVE RESPONSE
If the G.B. setting is too low a number, the response of minerals will be negative.
When the searchcoil is lowered to the ground in PinPoint or All Metal mode, the
machine will be silent. The machine will sound off as the searchcoil is lifted away
from the ground. What, if anything, you hear in Discrimination mode depends on
the Discrimination setting.
When searching in All Metal mode a
negative hot rock will produce a “boing”
sound after passing over it, making it difficult to know where it is located. It will
not have the sound and “feel” of a metal object.
CONTROL PANEL
GROUND BALANCING
GAIN versus THRESHOLD
“Gain” increases, or multiplies, the strength of signals from buried metal objects.
For maximum detection of the smallest or most deeply buried objects, increase
the Gain. To minimize the weakest signals, reduce the Gain.
“Threshold” controls the detector’s audio level. Positive threshold values
amplify the audio response of weak target signals. Negative threshold
values suppress sensitivity.
For searching at maximum sensitivity
, first set the gain at a low level. Then
set threshold into the positive region, with a comfortable background-hum
volume level. Then increase Gain to a comfortable level, free of chatter.
For silent searching
, set threshold to a negative number, and also reduce
Gain if necessary. Silent searching will result in the loss of some sensitivity.
TOUCHPAD CONTROLS
1. GG / PINPOINT
This button has a dual function, depending on the detection mode.
a. In DISC mode, press-and-hold the button to activate PINPOINT.
Pinpoint temporarily engages a no-motion detection mode. Searchcoil
motion is not necessary to detect metal. Any metal within the searchcoil’s
detection field will induce a sound. Pinpoint is generally used to verify a
target previously detected in Discrimination mode.
b.
In ALL-METAL mode, press-and-hold the button to activate GROUND GRAB.
Ground Grab allows you to set the detector’s internal ground setting equal
to the phase of the ground you are searching over. See the section on
Ground Balancing for a more thorough explanation of this feature and the
reason for using it.
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