13
Due to the sensitivity of the 1212-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 1212-X
does a good job of rejecting junk but it can be fooled by “hot”
mineralized spots in the soil, large 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, or 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 trash rejection level. Some other sources of false
signals are:
1. ELECTRICAL INTERFERENCE: Caused by radio/TV
stations, power lines, or nearby detectors
operating at the same frequency.
SOLUTIONS: Move further away, reduce sweep
speed.
2. HIGHLY MINERALIZED SOIL: Usually causes
constant static on good target sounds. SOLUTIONS:
Increase trash rejection level, 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 (see Figure 4) 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
the beeps or, if you sweep at right angles to your
original direction, you’ll receive a single beep
directly over the target (except for the very shallow
coin). One way to tell the difference between a
coin and a nail is to set your trash rejection to about
FALSE SIGNALS
