Gain Settings for Tracing a Cable or Line
You must use the proper Gain setting to obtain an optimum width null. A null is the audio signature that lets the operator
know when he is positioned directly over the target line. If you set the Gain too low, the null between the two signal
peaks (highest audio pitch) will cover too large an area, making it difficult to trace the line. If the sensitivity is set too
high, the null will be too narrow and very difficult for you to identify. You will find that setting the Gain to get the null
width as illustrated by the medium Gain curve in Figure 4-8 is the secret to successful tracing.
Figure 4-8. Null Shape Versus Gain Setting
Cable Tracing (HI Mode) Using Inductive Coupling
Position the transmitter over the target line and turn the power switch to ON. A steady beeping will be heard that indi-
cates the transmitter is operational. Move approximately 20 feet away from the transmitter along the suspected target
line before you start to trace the signal. This ensures that the receiver is not receiving the signal through air directly
from the transmitter. Adjust the Gain control for a medium pitch signal. Hold the receiver just below the large end as
illustrated in Figure 4-9.
Schonstedt Instrument Company
4-5
NOTE
Do not swing the receiver when pinpointing the
null. The null appears directly over the target
only when the receiver is held in a vertical posi-
tion. If it is held at an angle, the null will not
indicate the exact location of the target line.
TARGET CENTER
PITCH
INCREASE
AUDIO
OUTPUT
HIGH GAIN
MEDIUM GAIN
LOW GAIN
CABLE