Fisher 1225-X - Manual (Page 7)

5
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.
DISCRIMINATION POINTS