False Signals - Fisher 1266-X Operating Manual

FALSE SIGNALS

Due to the extreme sensitivity of the 1266-X, you're bound to
get some "false signals" once in awhile. A false signal occurs
when something that shouldn't sounds like a good target. The
1266-X does a good job of rejecting junk but it is so sensitive
that "hot" mineralized spots in the soil, large, can fool it pieces
of junk, some kinds of bottle caps and pull tabs or trash less
than 2 inches from the coil.
So what do you do about false signals? Well, 90 percent 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 also disappear if the coil is
speeded up or raised slightly. Some shallow, large or irregular
pieces of junk however, will sound off no matter what you do.
You may reduce the number of false signals by increasing the
discrimination level and/or reducing the sensitivity. Some other
sources of false signals are:
1. ELECTRICAL INTERFERENCE: Caused by radio/TV
stations, power lines, nearby detectors operating at
the same frequency. SOLUTIONS: Move further away,
lower the sensitivity, and reduce sweep speed.
2. HIGHLY MINERALIZED SOIL: Usually causes
constant static or good target sounds. SOLUTIONS:
Make sure you're in the normal "Pull" sensitivity
control position. Lower the sensitivity, increase the
discrimination, raise the search coil until false
signals disappear and sweep at that height.
3. WET SAND: Same as highly mineralized soil.
4. 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
buried coin on edge may give the same
response. In all cases, the target will be between
16