6 Using the vLoc-5000
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Pinpoint the Sonde as in the first procedure.
6.2
Passive or Active Location
There are two types of location method available with this system, they are:
6.2.1 Passive
Locating
Passive locating is locating buried utilities using the electromagnetic signals that exist in the environment. We
group these under two settings:
Power (P) – these are signals that generally originate from electrical power generation systems. These
are around 50/60 Hz and their associated harmonic.
Radio (R) – these are signals that are generally originated by low frequency radio transmissions. These
are generally in the range of 16 kHz to 22 kHz.
Passive location is used to search an area to see if buried metallic lines are present (known as locating to
AVOID). It does not help to identify what buried pipe or cable is present, only to confirm that there is a pipe or
cable there. A typical application would be to check an area before installing a fence post.
6.2.2 Active
Locating
Active locating is using a transmitter to apply a very precise frequency to a pipe or cable, and then using a
receiver turned to find the signal being radiated at that precise frequency. Active location frequencies can be
applied by direct connection, clamp or induction.
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