Fisher Labs CZ-21 QuickSilver Operating Manual page 33

FALSE SIGNALS
6. Wet Salt Water Sand: Your CZ-21 should be able to
handle most wet sand easily unless it's black. See
Black Sand above. You should able to reduce the
number of false signals caused by salt water by
lowering your sensitivity and making sure you are
ground balanced properly.
7. Hot Rocks: Some rocks, by virtue of their high mineral
content, will be seen by metal detectors as a metal
target. In the Autotune mode, the CZ-21 will respond
to most hot rocks. Prospectors must learn to distinguish
between hot rock and nugget sounds. In the
target I.D. mode, certain types of hot rocks will be
automatically rejected at DISC = "0" and virtually all
other hot rocks will be identified as iron or rejected
at DISC = "1."
8. "End of Swing:" Silent search motion detectors often
give false signals at the edges of the search pattern,
just as the coil stops and begins accelerating back
toward the operator. If this is a problem, try one or
more of the following:
9. Digging Tool: If you're carrying a metal sand scoop,
digging knife, or screwdriver, hold it behind your back
or keep it above your waist. Your CZ-21 is sensitive
enough to sound off each time you sweep the coil
beneath it.
10. Elongated Ferrous Objects: If you get two beeps
close together and can't find either target, you may
be near a nail or some other long, ferrous object.
Fortunately, in most cases your CZ-21 will identify
these objects correctly. In all cases, the target will be
between the beeps, or if you sweep at right angles
a) Keep your sweep smooth, slow and low to the
ground.
b) Check your ground balance.
c) Lower your sensitivity.
d) Make sure your search coil is properly secured
and the cable connector is firmly tightened.
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