Vivax Metrotech 4.04.000170, User Handbook Manual

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3 Using the vLoc3 RTK-Pro
3. Using the vLoc3 RTK-Pro
3.1 Passive Locating
NOTE
The compass indicator is not active during the passive location.
Passive locating refers to the process of detecting signals that “naturally” occur on pipes and cables. These tend to fall into two
categories, radio signals and power signals.
Radio signals - Low-frequency radio transmitters create radio signals. These are used for broadcasting and communications
and are positioned throughout the world. As the frequencies are very low, the signals tend to penetrate and hug the earth's
curvature. When the signals cross a long conductor such as a pipe or cable, the signals are re-radiated. It is these re-radiated
signals that the Radio mode can detect.
Power signals
- are created by mains power running in the supply cables. These signals are 50 or 60Hz, depending on the
country. For instance, the UK is 50Hz power, but the USA has 60Hz. When electrical power is distributed throughout the network,
some power finds its way back to the power station via the ground. These stray currents can jump onto pipes and cables and
also create power signals. Note that there has to be an electrical current flowing to create a detectable signal. For instance, a
live cable that is not in use may not radiate a detectable signal. Also, a very well-balanced cable, i.e., the same current flowing in
live and neutral, will cancel out and may not create a signal. In practice, this is unusual as there are usually enough imbalances
in the cable to create a good detectable signal.
3.1.1 Detecting Power Signals
1. Switch on the vLoc3 RTK-Pro receiver and select Power mode using the “f” button. Notice that the antenna mode indicator
will be showing “Peak” or “Omni peak,” as these are the only options in the passive modes.
51.6
Power 50 40dB
4G
2. Hold the vLoc3 RTK-Pro vertically and away from likely positions of cables or pipes.
3. Adjust the sensitivity using the “+ “ and “-“ buttons so that the bar graph reading is just starting to show some movement.
Note that the compass feature is not available for the Power or Radio modes.