
Dealing with clutter Signals (HI Mode)
When using induction to apply the tracing signal, an effective method of reducing interference caused by parasitic
signals from an adjacent line is to fins a second spot on the line that has a good clean null (equal strength lobes on both
sides). Move the transmitter to this spot. Confirm that this is the target line by backtracking with the receiver to the first
site of the transmitter and checking for a null. This procedure of leapfrogging the transmitter is also the standard
method for extending the tracing range on electrically poor or leaky lines.
Figure 5-4. Repositioning Transmitter to Reduce Interference
Single-Lobe Identification (HI Mode)
A second line parallel to the line being traced will emit a parasitic signal but at a reduced strength. Interaction of these
signals results in unequal side lobes, which cause a large null off to one side of the target line as indicated by signal
pattern curve A in Figure 5-5. To accurately trace a line under this condition will require practice. An alternate method
is to hold the receiver in a horizontal position perpendicular to the line and listen for a single high pitch audio signal that
occurs directly over the line as indicated by signal pattern B.
Figure 5-5. Single Lobe Identification Technique
Schonstedt Instrument Company
5-3
SIGNAL A
SIGNAL B