26
Ground balancing
–
technical info
Fe
3
O
4
BARGRAPH
The Fe
3
O
4
7-segment bar graph indicates the amount of ground mineralization,
independent of type, expressed as an equivalent volume concentration of magnetite
(Fe
3
O
4
). It updates every second. It is sensitive to motion and will give the most accurate
readings if you pump the search coil up and down several times over the ground. The
presence of metal or “hot rocks” will cause the readings to be inaccurate. If you stop
moving the search coil, the bar graph will go blank
Indication
Relative
mineralization
% Fe
3
O
4
Susceptibility
7 Bars
High
Over 1
Over 2500
2 to 6 Bars
Medium
0.26 -1.0
61-2500
1 Bar
Very Low
0.006-0.25
15-60
None
---
Less than 0.006
Less than 15
Magnetic susceptibility is expressed in micro-cgs units. In a saltwater environment in the
absence of iron minerals, the bar graph indicates relative electrical conductivity.
In soils with greater than 10,000 micro-cgs units’ magnetic susceptibility. The signal from
the soil may saturate, or overload, the circuitry. This will not harm the detector but the
machine will not be usable in that condition. The solution is to hold the search coil
several inches above the soil surface s it is not “seeing as much dirt”. By listening and
watching you will know how high you need to hold the search coil in order to avoid
overload.
The highest magnetic susceptibilities are usually found is soils developed over igneous
rocks, in alluvial black sand streaks on beaches, and in red clay soils of humid climates.
The lowest magnetic susceptibilities are usually found in white beach sands of tropical
and subtropical regions, and soils developed over limestone.
Target display and audio
Signal Indicator
The lower-left bar graph designates SIGNAL strength only when operating in DISC Mode.
The signal strength indicator at the bottom-left of the screen indicates how large or
close the buried metal target is.
If all bars are illuminated, the target is large or close to the search coil.
If one or two bars are illuminated, the target is far away or small, or both.
