False Signals - Fisher Lab CZ-21 QuickSilver Operating Manual

FALSE SIGNALS

A "false signal" occurs when a target is incorrectly identified. For
example , a small, broken-off piece of pull tab may be identified
as a nickel. Or a small, deep coin, especially in mineralized soil,
may read "IRON." The more sensitive the metal detector, the
harder it is not to have false signals. Your CZ-21 is an extremely
sensitive machine, so you're bound to encounter them. Here are
some of the most frequent sources of false signals and what to
do about them:
1. Trash: The most common source of false signals.
Large or irregular pieces of trash may give good,
consistent, high-tone signals. In this case you'll usually
have to dig the target, but with experience you'll be
able to eliminate many of the large targets whose
size will be obvious when you go into the pinpoint
mode. Another false signal response may be a "one-
way" or disappearing signal. You'll sweep over the
target and get a good signal but nothing on the
return sweep. When this happens you're over a
target that the CZ-21 can't positively identify due
to its size, shape, depth or alloy. The CZ-21 may I.D.
it as a coin when swept from one direction and iron
on the return sweep.
If your DISC control is set at "0" you'll hear first
a high tone (coin) and then a low tone (iron). Or if
your DISC control is set higher, to reject iron, you'll
hear the high tone sweeping one way and nothing
the other way.
Quite often the signal will just disappear and you
won't be able to find it no matter which direction you
sweep. These one-way and disappearing signals are
usually trash, and as a general rule you should ignore
them. If you have any doubts, tap the PINPOINT
button to get an accurate location, and then I.D. the
target. If you get a good repeatable tone, dig it. If you
still get a one-way signal or it disappears, move on.
Also, if your pinpointing location is different than your
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