sensitivity of the receiver, turn the SIGNAL LEVEL
control in the clockwise direction, keeping the
response between 1/4 to around 3/4 scale. When the
signal from the line has faded so that it is no longer
detectible, push the SENSITIVITY button so that the HI
light glows. You may then continue tracing as before.
vi) At any time while tracing, you may determine the direc-
tion and depth of the line. To determine the direction,
rotate the receiver left and right as shown in
Figure 9
.
Notice that rotating the receiver will cause a peak
response as well. When the response is maximum, the
receiver box is parallel to the direction of the line. For
information on determining line depth, see part (c) of
this section.
vii) If, while tracing, the signal suddenly vanishes along the
direction you are moving, then the line either ends at
that point or it has turned to the right or the left.
Figure
10
depicts a simple way to determine if the line has
turned. Walk back up the line about four feet and then
walk in a circle either right or left. Keep the side of the
receiver box pointed toward the center of the circle. If
a lateral turn exists, the receiver will peak over the line,
giving the direction of the turn. If the line simply ends,
then no other strong peaks will be detected.
viii) If, during tracing, the signal gradually fades and the
receiver is set to its highest sensitivity, then you may
continue tracing by bringing the transmitter closer and
reenergizing the line at a point you have already
located. Usually, you would use inductive energizing
when moving the transmitter closer, but connecting to
a nearby part of the line that is exposed is preferred.
Model 902 Pipe & Cable Locator
17
