7 Tracing Techniques and Helpful Information
For best results, use the Direct Connection method of coupling signal to the targeted
conductor. (Section 4.1)
7.7 What is Field Strength of the Signal?
When the signal is applied to the conductor using any of the three methods described
in Section 5, an electromagnetic field is created on the conductor. The Receiver
measures the strength of this field, displaying it on the digital meter.
The field strength decreases as you move away from the target conductor and as you
go farther away from the Transmitter.
7.8 “Ghost” Conductor Due to Adjacent Conductor
If there is another conductor near the target conductor, it too may pick up the signal
from the Transmitter. When this occurs, there will seem to be a trace – a “ghost” trace
– between the two conductors.
A ghost trace can be detected by noting the following:
1. When the Left/Right Guidance needle changes direction and the tone changes
from broken to solid or solid to broken and the Left/Right Guidance meter
needle moves in the same direction as you are moving. (Normally, the Left/Right
Guidance needle moves in the opposite direction.)
2. The field strength reading will drop as you move toward the “ghost” conductor.
(Normally, field strength would increase.)
3. If you take a depth measurement over a “ghost” conductor, you will get a random
or “Error” reported.
The Receiver reads a “ghost” conductor when each coil on each side of the cross
section of the antenna receives the same amount of signal from two separate
conductors.
The location of the “ghost” will vary, according to the size, depth, and conductivity of
any adjacent conductors.
To re-establish the correct trace, backtrack and search the area in a 180º arc.
7.9 Completing the Circuit Path
Ground on Either Side of Trace Area
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