GROUND BALANCING -Technical Info
Fe3O4 BARGRAPH
The Fe3O4 4-segment bargraph indicates the amount of ground mineralization, independent of type, expressed as an equivalent volume concentration of magnetite (Fe3O4). 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 bargraph will go blank.
INDICATION | % Fe3O4 | SUSCEPTIBILITY |
4 Bars | -High | 0.4 - 1.6 | 1,000 - 4,000 |
3 Bars | -Medium | 0.1 - 0.4 | 250 - 1,000 |
2 Bars | -Low | 0.025 | - 0.1 | 60 - 250 |
1 Bars | -Very Low | 0.006 | - .025 | 15 - 60 |
none | - - | less than .006 | less than 15 |
Magnetic susceptibility is expressed in micro-cgs units. In a salt water environment in the absence of iron minerals, the bargraph indicates relative electrical conductivity.
In soils with greater than 4,000 micro-cgs units magnetic susceptibility, the signal from the soil may saturate (“overload”) the circuits. 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 so it isn’t “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 in 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.
Ground Error
The bottom left-hand corner of the display contains a graphic which indicates if your detector’s ground balance setting needs to be adjusted.
The Omega has a tracking system which continuously analyzes the phase of the ground you are searching.
It then compares this ground phase value with the detector’s internal Ground Setting indicated on the bottom right of the display.
*If the detector’s internal Gound Setting is equal to the actual phase of the ground, the detector is properly ground balanced and the Ground Error window is clear.
