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SeekTech SR-60
Figure 22: Tracing Line Showing
High Distortion
3.
Use the Guidance Arrows, Proximity Number, Signal
Strength, and Tracing Line to guide the line trace. These
pieces of information are generated from discrete signal
characteristics to help the operator understand the qual-
ity of the locate. An undistorted signal emitted from a line
is strongest directly over that line. (Note: Unlike the Signal
Trace lines, the guidance arrows require that the user orient
the locator so that the guidance arrows point 90 degrees to
the Signal Trace line. (See figure 23.))
Note: An undistorted line will also be clear rather than
blurred on the screen, and the sound accompanying the image
will have no "static" in it.
Note: Confidence in the accuracy of a locate can be increased
by maximizing the Proximity Signal (and/or Signal Strength), bal-
ancing the Guidance Arrows and centering the Tracing line on
the screen. Confirm a locate by testing whether the Measured
Depth reading is stable and reasonable. Agreement among all
these indicators means the probability of an accurate locate is
high.
Maximized
Figure 23: High Probability Locate
As always, the only way to be certain of the location of a utility is
through visual confirmation by exposing the utility.
16
The accuracy of position and depth measurement improves as
the SR-60 lower antenna node is placed closer and closer to the
target utility. Rechecking the Measured Depth and position pe-
riodically during the excavation process can help avoid damage
to a target utility and may identify additional utility signals that
were not noticed prior to excavation.
When line tracing, it is important to remember that tees, curves,
other conductors in the vicinity, and nearby masses of metal can
add distortion to the field, requiring closer scrutiny of the data to
determine the true path of the target utility.
Clarifying the situation can be done by assessing whether the
distortion is due to a poor signal that needs to be improved, a lo-
cal interference such as a near-by car, or a tee or turn in the line.
Circling the last location of a clear signal at a distance of about
20 feet (6.5 m) can clarify if the distortion is coming from a local
turn or tee in the line, and enable the operator to again pick up
the line nearby.
Always cross check the locate by ensuring that:
The Tracing Line shows little or no distortion response
(blurriness).
The Proximity Signal and the Signal strength maximize
when the Tracing Line crosses the map center.
The Measured Depth increases appropri ately as the
unit is raised vertically and the Tracing Line remains
aligned.
Measured Depth readings should be taken as estimates and
actual depths should be independently verified by pothol-
ing or other means prior to excavating.
Care should be taken to watch for signal interference
that may give inaccurate readings. The Tracing Line is
only representative of the position of the buried util-
ity if the field is UNDISTORTED. Do NOT base a locate
solely on the Tracing Line.
If the signal is clear, the SR-60 will often show a straight signal
line with very little distortion right up to a 90-degree tee, show
a small amount of distortion as it follows around the curve, and
Maximized
then show a clear signal again as it resumes its travel after the
tee. It shows very clearly when the line is turning.
Ridge Tool Company
WARNING
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