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FALSE SIGNALS
A "false signal" occurs when something that shouldn't, sounds
like a good target. Your 1225-X does an excellent job of ignoring
junk but it's so sensitive to good targets that it can be fooled by
bad targets with similar electrical characteristics. Large pieces
of trash for example, or even some kind of bottle caps and pull
tabs. Small pieces of trash less than 2 inches from the search
coil will also sound good occasionally.
So what do you do about false signals? Well, 90% of them will
sound suspicious to you after you've had some experience and
you'll just ignore them. They may be very faint or very abrupt
with static. Often when you go back over the same spot, a false
signal will simply disappear. Other false signals may be very loud
and sharp but most of these will disappear if the coil is speeded
up or raised slightly. Some shallow, large or irregular pieces of
junk however, will fool the 1225-X no matter what you do. Here's
some other sources of false signals and what to do about them:
1. DETECTOR INTERFERENCE: Caused by nearby
metal detectors operating at the same (or close)
frequency.
SOLUTIONS: Move further away or reduce
sensitivity.
2. ELECTRICAL INTERFERENCE: Caused by Radio/TV
stations, power lines, etc.
SOLUTION: Move further away, lower the
sensitivity, reduce sweep speed. Wrap the search
coil cable tightly around the stem.
3. HIGHLY MINERALIZED SOIL: Usually causes
constant static or good target sounds. SOLUTIONS:
Lower the sensitivity, increase the discrimination.
Raise the search coil until false signals disappear
and sweep at that height.
4. WET SAND: Same as highly mineralized soil.
5. ELONGATED FERROUS OBJECTS: If you hear two
beeps very close together and can't find either
one, you're probably over a nail or some other
long iron object. But a very shallow coin or a coin
on edge will give the same response.
SOLUTIONS: In all cases, the target will be
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1225xManual-8702520.indd 7
DISCRIMINATION POINTS
By adjusting the DISC ("Discrimination") control, you will be
able to ignore or ("reject") small pieces of metallic target trash
and ground minerals while detecting valuable targets. The
lowest setting at which an object is rejected is reffered to as its
"discrimination point." Discrimination points are determined by
such factors as size, shape, depth, type of metal and ground
mineralization.
1. Scatter some sample targets such as coins, pull
tabs and small pieces of foil on the ground 1 to 2
feet apart.
2. Turn the 1225-X on by turning the DISC control to
zero.
3. Set the SENS control to 8.
4. Hold the search coil in the air, away from any metal
objects and check the batteries as explained in the
Control Function section (sensitivity control).
5. Hold the search coil in the air about 2 inches
above and parallel to the ground. Move it slowly
over the samples and note the sharp loud response
as you pass over each one. Keep in mind that the
1225-X is a motion detector in the DISC mode and
responds only when the search coil (or the target)
is moving.
6. Increase the DISC control to a setting of 3 and
again pass over the targets. Repeat this process at
settings of 4, 5, 6 and so on to 10. You will note that
as you increase the level of discrimination, the 1225-X
will reject some targets and continue to respond to
others. You have now determined the discrimination
points for the rejected objects. For example, the
small nail discrimination point may be at 3 and the
pull tab discrimination at 7.
7. Some objects such as shallow bottle caps, bent
pull tabs or trash less than 2 inches from the coil may
be difficult to reject. The 1225-X will instead respond
with a broken signal which will usually disappear if
the search coil is raised slightly. The strong signal of
a good target will usually get weaker when the coil
is raised.
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6/9/06 10:07:20 AM
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