Vivax Metrotech 4.04.000170, User Handbook Manual

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3 Using the vLoc3 RTK-Pro
If the Omni mode is selected, the locator's orientation is not important, but it is still necessary to pinpoint the line accurately
before taking a depth measurement.
The signal current value will also be displayed. This feature is useful for confirming that the detected signal is radiating from
the correct line. If the signal is “bleeding off” onto other services, these signals will generally be less than that of the originating
signal. However, care should be taken as the signal current will gradually reduce over the length of the line, but watching for a
sudden drop in current over distance should indicate that either:
1. There is a ground fault on the line, which is a shunting signal to the ground.
2.
There is a “Tee” off from the mainline.
3. The operator has migrated from the connected line to a line with some signal bled across from the mainline.
4G
Log
29
50°42′59.90570′′N
3°26′35.54358′′W
63.3mA
27.50m
0′1′′ (2DRMS)
NOTE
If a valid GNSS/RTK fix is available, an additional screen with a
spirit level similar to the screen at the right will be shown.
It is possible to log this data into the receiver's internal memory.
This is explained in detail in the “Datalogging” section.
3.8 Distorted Fields
Always be aware that you are locating the signals radiating from the buried line. These radiated fields can be distorted by other
lines or electromagnetic signals from buried lines. Metallic structures like crash barriers or wire mesh fences can also help to
distort signals.
vLoc3 series receivers can detect the presence of possible distortion. The Vector screen has a circle drawn around the target
line, which increases in size in the presence of possible distortion. The Plan view screen has “Tram” lines on either side of the
calculated position, which moves further from the line as possible distortion is detected.
However, when using the traditional screen, the risk of an inaccurate location can be reduced further by doing the following:
• Check to see if other radiated fields are distorting the signal. Locate the cable, first in the “Peak” mode and then in the “Null”
mode (or use the left/right arrows). The two locations should indicate that the cable is in the same place. If they do not, the
signal field is distorted, and the depth and current measurement may be inaccurate.
2
1
3
1 Null Position
2 True Position
3 Peak Position