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8
Using the vLoc-9800
8.3.5
Tracing a Buried Line
Once a buried line is located it is generally necessary, and a good practice, to trace that line for some
distance in both directions. Whenever practical it should be traced to a point that provides additional
confirmation of what type of service is being located (a telephone pedestal, a manhole cover etc). If tracing a
line to which a transmitter signal has been applied, one should trace out from the transmitter connection point.
The receiver should be held level to the ground and rotated in a small arc across the anticipated route of the
buried line. A clear response should be visible on the display and heard audibly.
8.3.6
Pinpointing & Confirming the Buried Line
Marking the exact position of the buried line is generally called pinpointing. Pinpoint the line before marking
its position. Place the receiver in "Peak" or "Left/Right" mode, pass the blade of the receiver across path of
the cable and identify the peak response on the display and/or audibly.
8.3.7
Distorted Fields
When locating always be aware that you are locating the signals radiating from the buried line, and these
radiated fields as they are called can be distorted by other lines or electromagnetic buried lines or metallic
features like crash barriers or wire mesh fences. The risk of an inaccurate location can be reduced further by
the following:
To check if the signal is being distorted by other radiated fields. First locate the cable in the either mode.
•
Place the locator on the ground and take a depth reading by pressing the "i" pushbutton. Note the result
and then raise the locator approximately 1.5ft (0.5m) Take another depth reading and check the depth
has increased by this amount. If it has, the depth is likely to be correct. If it has not, then the depth is not
likely to be correct because the signal is distorted.
Page 44
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