c. Variometer Phasing and Sensitivity Check-. Refer
b. Starting. Refer to figure 2-4 and start the mine
to figures 2-6 and 2-6.1 and check the mine detector for
variometer phasing and sensitivity. If the detector does not
2-6.1, turn the detector in for repair.
Refer to figure 2-4 and stop the mine detector set.
d. Using the Detector Head. Refer to figure 2-7 for
proper positions and use of the detector head.
Do not leave the battery in the mine detector set when
the set is not in use. The battery will sometimes corrode,
causing damage to the terminals inside the battery
housing. (Refer to fig. 2-1 for removal of battery).
If more than one mine detector set is being used in the
area, keep the detector heads at least 20 feet apart, to
2-10. Mine Detector Set Operation
be heard when units are operating too close to each
a. Genera/. The mine detector set functions
electronically as an audio frequency, mutual inductance
bridge. The coils in the detector head, comprising the
mutual inductance bridge, are electrically balanced. The
transmitter coils send out electromagnetic waves, setting
up a magnetic field with a radius of from 3 to 4 feet around
Cease searching suspected mined area if the usual low
the detector. When a metallic object is encountered, the
level (2,500 cps) signal changes to a sharp piercing high
magnetic field set up by the detector head becomes
level signal. When battery voltage drops below 7 volts
distorted. This distortion results in an unbalance in the
the output amplifier module automatically induces a
mutual inductance bridge resulting in a signal increase in
low raspy signal. Operation of equipment during this
the headset. A phase discriminating circuit built into the
condition imperils life as voltage is below the required
mine detector set cancels out false signals caused by salt
minimum level for detection of metallic objects.
water or magnetic soil. Only signals caused by metallic
objects are transmitted to the headset. Figure 2-5 illustrates
the mine detector set circuits in block diagram form.
The detector head cover (fig. 2-8) must be installed on
the search head whenever the detector is operated on
rough terrain to pervent damage to the search head.
Do not operate the mine detector set if it is improperly
adjusted. Cease searching suspected mined areas
e. Buried Metallic Object Encountered. A noted
immediately if faulty signal responses or other
increase in the headset signal volume as the detector head
indications of improper operation are detected.
is moved over the ground, is an indication that a metallic
object is buried in this particular area. Proceed to locate the
exact position of the buried metallic object as outlined in
Do not operate detector unless yellow with black stripe
output amplifier module is installed. Output amplifier
modules other than the yellow with black stripe may
not alert the operator of low battery voltage. Detectors
Alwasys keep the detector head parallel to the ground
operated with low battery voltage will not detect
during a search operation. Never allow the detector
metallic objects, which endangers the life of the
head to drop or rest on the ground during mine
detecting operations in a suspected area.
f. Searching Areas that Are Covered With Metal
Do not operate the mine detector set prior to
performing preliminary adjustment and sensitivity
check. Faulty signal repsonses or other indications of
improper operation endangers the life of the operator.
Be extremely careful when searching an area that is
covered with metal fragments as there is danger of
Signal. Refer to figure 2-4 and adjust the controls for a
encountering metallic mines yielding signals that might
be mistaken for those caused by the metal fragments.