False Signals - Fisher CZ-20 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-20 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-20 can't positively identify due to its
size, shape, depth or alloy. The CZ-20 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, press 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 I.D. location, your target is
probably a piece of iron. Reducing your
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