that it can detect the signal in different response modes
depending on how it is positioned. By manipulating the
receiver over the line and properly interpreting the results,
an operator can perform several locating tasks with high
accuracy.
a) Peak Detection Method
Tracing a line by finding maximum points of signal, or
“peaks”, is the most intuitive method of tracing, although
not the most accurate. Both location and direction of a
line can be determined simply by positioning the 902
receiver so that it indicates a maximum relative response.
The following steps illustrate how this is accomplished.
i) After having energized a pipe or cable, turn on the
receiver. At first, set the sensitivity to low (HI light off);
also, make sure that the LOCATE MASS feature is
deactivated (LOCATE MASS light off).
ii) If you are using inductive energizing, walk down the
line 20 or 30 feet, moving further out of range of air
signals coming from the transmitter. If you are using
conductive energizing, you may begin tracing close to
the transmitter.
iii) Hold the receiver vertical and in the approximate direc-
tion of the line as shown in
Figure 8
. Adjust the
SIGNAL LEVEL control so that the receiver responds
to the signal from the line at around 3/4 scale.
Model 902 Pipe & Cable Locator
15
