RIDGID SeekTech SR-20 - Manual (Page 11)

Ridge Tool Company 0
Tools For The Professional TM
seekTech sR-20
Figure 20: Tracing Line Showing High Distortion
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 quality
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 21).
5. Note that 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.
6. Confidence in the accuracy of a locate can be
increased by maximizing the Proximity Signal (and/
or Signal Strength), balancing 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. (See page 12.)
Figure 21: High Probability Locate
WARNING: 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 utility if the field is UNDISTORTED. Do NOT base a
locate solely on the Tracing Line.
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 appropriately 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
potholing or other means prior to digging.
As always, the only way to be certain of the location of a
utility is through visual confirmation by exposing the utility.
The accuracy of position and depth measurement improves
as the SR-20 lower antenna node is placed closer and closer
to the target utility. Rechecking the Measured Depth and
position periodically 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.
See below for tips on improving the signal.
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.
If the signal is clear, the SR-20 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 then show a clear signal again as it resumes
its travel after the tee. It shows very clearly when the line is
turning.
Tracing Line
Tracing Line