Line Tracing; Active Line Tracing - RIDGID SeekTech SR-20 Operator's Manual

SeekTech SR-20
Figure 19 – Menu Key
Sounds of the SR-20
The sound level is driven by the proximity to the target.
The closer to the target, the higher the sound pitch will
be. A rising tone indicates increasing signal.
In Line Tracing modes, the default distortion response also
activates an audio signal proportionate to the distortion in
the detected field. When there is no distortion present, the
sound of the SR-20 is a clear warbling sound when on the
left side of the detected field, with a slight click added
when on the right side of the detected field. If distortion is
detected a sound similar to AM radio static sound can be
heard, which gets stronger as the degree of distortion in-
creases. If the distortion response feature is disabled, the
static sound does not occur.
In Sonde Mode, if the sound level reaches its highest
point, it will "re-scale" to a medium level and continue sig-
naling from the new starting point. Moving away from
the Sonde, it will drop to a lower pitch and remain there as
long as one moves away from the Sonde. Moving back to-
ward the Sonde it will resume rising in steps starting
from the level it had reached previously.
If desired, force the sound to re-center at a medium
level (in any mode) by pressing the Select Key during
operation.
Keys to locating with the SR-20
SIGNAL STRENGTH represents the strength of the field
being detected by the lower antenna node of the SR-20.
In a clear and undistorted field, you can locate based on
Signal Strength alone.
PROXIMITY SIGNAL reflects the proximity of the locator
to the target utility; the closer the locator moves to the cen-
ter of the detected field, the higher the Proximity Signal
number gets. The Proximity Signal is calculated from
the ratio of the signals received at the lower and upper an-
tennas, adjusted for scalability.
DISTORTION is the degree to which the field detected is
deformed from the simple circular shape. If multiple fields
are present, the detected field is pushed or pulled out of
12
shape and the different antennas will pick up different field
strengths.
GUIDANCE ARROWS are driven by the signals received
at the side antennas of the SR-20. When the fields de-
tected by these side antennas are equal, the arrows will
center. If one is receiving a stronger field signal than the
other, the arrows will point toward the probable center of
the target conductor.
Line Tracing with the SR-20
There are two major ways to look for lines underground
with the SR-20. They are called Active and Passive. The
difference is that in Active Line Tracing, a current is
placed on a conductor using a transmitter, and that spe-
cific signal is then sought for using the locator. Passive
tracing does not use a transmitter and listens for any
signal that may be picked up at particular frequencies.

Active Line Tracing

In active line tracing, underground lines are energized
with a Line Transmitter. This active signal is then traced
using the SR-20. A Line Transmitter is different from a
Sonde in that it is used for tracing an energized line,
rather than acting as a target for a locate. Line trans-
mitters energize lines by direct connection with clips, by
directly inducing the signal using a clamp, or by inducing
the signal using inductive coils built into the transmitter.
Connect the ground lead and the power lead of
the transmitter before powering the transmitter
on, to avoid electric shock.
1. Energize the target conductor according to the
transmitter manufacturer's instructions. Select the
transmitter frequency. Set the frequency used on the
SR-20 to the same frequency used on the trans-
mitter.
Direct Connect Method: The transmitter is attached by
direct metal-to-metal connection to the target conductor
at some access point such as a valve, a meter, or other
point.
IMPORTANT! The connection between the trans-
Inductive Clamp Mode: The transmitter is connected to
an inductive clamp which is then closed around a pipe or
cable. The transmitter energizes the clamp, which then
induces a current in the conductor.
Ridge Tool Company
WARNING
mitter and the conductor must be a
clean, firm connection. The transmitter
must also be connected to a ground
with a strong open path to ground.