OKM eXp 6000, User Manual

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Operating modes 47
vertical position. Do not bend over to bring the antenna closer to the ground. It is designed to be higher
above the ground to eliminate some of the smaller signals that can create false anomalies within the
scan.
Prior to beginning the scan, some important items that one needs to remember is:
•
Create a path and be sure that it is free and clear of obstacles.
•
The path must be straight.
Pulling a line or rope from the beginning to the end of the path is advised.
•
Be sure that during the scan the antenna is held at the same height.
•
The speed or distance between impulses needs to be the same.
Changing the speed will result in an inaccurate scan.
•
Complete the control scan.
A control scan is a repeat of a scan using all the exact same parameters.
When all the scanning is done correctly, conducting the data analysis is much easier.
The single line method is also a very accurate way of locating deeper voids and tunnels. When the single
line method is used, the chances of making an error is greatly decreased. This method is used for an
initial investigation of an area.
In the example from figure 6.11 the void is circled to show the location. A scan like the one above will be
repeated several times to ensure that the void is real and that it also does not move.
The repeating of the scans is also known as control scans.
A note to remember is that the bigger the tunnel opening or void is, the deeper the tunnel can be
detected. If the tunnel is very small then the maximum depth will be decreased and may be difficult to
find. The depth of a tunnel cannot be accurately determined. The Visualizer 3D software is designed to
measure depth starting from the surface disturbance to the object itself.
OKM GmbH
www.okmmetaldetectors.com
Figure 6.11: Single line method used to locate tunnel