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Version 1.27
Estimating the depth using the Half-Width Method 6.5.3
The farther away the operator is from the object, the smaller the interference field of the
ferromagnetic object. This property is used to determine the size of the object and its depth in the
ground. The depth of the object in the ground can be determined by using the half-width method
whenever the interference field of the ferromagnetic object is not influenced by any other objects.
While determining the half-width value, the measurement range setting must not be
modified. Also maintain a constant distance between the probe and the ground.
Step 1: Mark the minimum and maximum
Mark the spot where you have the strongest positive reading, then do the same at the spot with the
largest negative reading. Draw a line between those two marks.
Step 2: Marking the Area around the Absolute Maximum Value
Starting from one of the marks (this can be the maximum or the minimum), walk along this line
towards the other mark until the displayed value has reached half of the absolute maximum value.
This spot is now marked.
Next return to the spot you’ve started from and walk in the opposite direction along the line
mentioned above. Keep walking until the displayed value has reached half of the absolute maximum
value. This spot is also marked.
Step 3: Measuring the Half-Width Value
The distance in between the two marked spots (halved maximum value) is now measured (in
meters). This value is known as half-width value.
Step 4: Calculating the approximate depth of the object
By using the following formula and the determined half-width value, the approximate depth of the
object in the ground can be calculated.
T = object depth
5/4 = empirically determined factor
D = half-width value