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ELECTROMAGNETIC INTERFERENCE
The principle use for the Sensitivity Control is to eliminate
Electromagnetic Interference (EMI).
A hobby metal detector is an extremely sensitive device; the search coil
creates its own magnetic field and acts like an antenna. If your detector
beeps erratically when the search coil is motionless, the unit is probably
detecting another magnetic field.
Common sources of EMI are electric power lines, both suspended and
buried, motors, and household appliances like computers and
microwave ovens. Some indoor electronic devices, such as dimmer
switches used on household lighting, produce severe EMI and will cause
the detector to beep erratically. Other metal detectors also produce their
own electromagnetic fields, so if detecting with a friend, keep two metal
detectors at least 20 feet apart.
If the detector beeps erratically, REDUCE THE SENSITIVITY by pressing
the Down-Sensitivity Arrow on the left of the control panel.
SEVERE GROUND CONDITIONS
A secondary use for the Sensitivity Control is to reduce false detection
signals caused by severe ground conditions. While your Discovery 1100
contains circuitry to eliminate the signals caused by most naturally
occurring ground minerals, 100% of all ground conditions cannot be
anticipated. Highly magnetic soils found in mountainous and gold-
prospecting locations can cause the detector to emit tones when metal
objects are not present. High saline content soils and sands can also
cause the detector to false.
If the detector emits false, non-repeatable, signals, REDUCE THE
SENSITIVITY.
MULTIPLE TARGETS
If you suspect the
presence of deeper
targets beneath a
shallower target, reduce
the sensitivity to
eliminate the detection
of the deeper targets, in
order to properly locate
and identify the
shallower target.
SENSITIVITY ADJUSTMENT
