Fisher Research Labs F70 User Manual page 22

OPERATING MANUAL
LCD Visual Display (continued)
Since different metal objects can produce similar signals, and since minerals in the soil can
distort the signals, the probable target ID's are just that -- probable. There is no way of
knowing for sure what's buried other than to dig it up. Experienced metal detector users have
a rule of thumb -- "when in doubt, dig".
TARGET
The target indicators are at the top edge of the
display. When a target is detected, a rectangle-like
indicator will illuminate over the target category
corresponding to the target's electrical characteristics.
DEPTH
When the PINPOINT is pressed-and-held to facilitate
pinpointing an object, the numerical display indicates
the approximate depth of the object, in inches,
based on the assumption that the object is a typical
U.S. coin. Small objects will read deeper than they
actually are, and large objects will usually read
shallower than they actually are.
CONF (Target Confidence Indicator)
This 4-segment graphic indicates how confident the detector is of the 2-digit target identification
it has assigned. If all 4 segments are displayed, the detector is confident that the target ID is
accurate. If 2 or fewer segments are displayed, the confidence is low. If no segments appear
when the 2-digital ID is displayed, the detector has no confidence that the value is accurate; it
has assigned its best guess. Junk targets tend to produce lower confidence indications than
coin targets of similar electrical conductivity. Sloppy sweep technique also reduces the
confidence indication. You can use this indicator to train yourself to sweep more skillfully.
DIRT (Ground Mineralization Indicator)
This bar graph displays the relative amount of magnetic mineralization (i.e. magnetic
susceptibility) of the soil. The primary magnetic minerals in most soils are magnetite (black
sand), and maghemite (a red clay mineral). The depth to which objects can be accurately
identified is strongly influenced by the magnetic susceptibility of the soil. High values (4 bars)
have a greater effect on detection depth in the Discrimination mode than in the Autotune mode.
For the most accurate DIRT reading, pump the search coil as though you were ground
balancing.
DIRT
BARS Description
4 Uncommonly heavy mineralization
(not uncommon in goldfields)
3 medium mineralization
2 light mineralization
1 very light mineralization
blank White beach sands
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GUIDE TO METAL DETECTING