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4 Using the vLoc3-DM Receiver
4.2 Active Locating - Applying the Locate Signal using the Loc3, 25-Watt
Transmitter
Active locating uses a transmitter to apply a precise frequency to a pipe or cable, then uses a receiver turned to detect the signal
being radiated at that precise frequency. Active location frequencies can be applied by direct connection or signal clamp. This is
further explained in the following sections.
Unlike passive detecting, active locating has the benefit of the operator controlling the signals and can be more specific about
what line is detected. Passive signals are also not always present on a line so using active signals ensures more lines are
detected.
Choosing the correct frequency depends on the application and the environment. As a rule start with the lowest frequency you
have available. Lower frequencies travel further with less bleed off onto nearby utilities than higher frequencies.
When using the signal clamp with the Loc3-25Tx (25-watt transmitter), the clamp frequencies available are limited between 8kHz
and 10kHz.
A transmitter is required to apply a locate signal. Depending on the transmitter model the transmitters locate signal can be
applied by direct connection or transmitter signal clamp.
4.2.1
Direct Connection
This method involves making an electrical connection to the cable or pipe.
WARNING
The direct connection leads are not designed for connection to live cables.
WARNING
Do not touch metal parts of the connection clips when connecting to the line or when the transmitter
is on.
WARNING
Only authorized personnel should make connections to cables.
To make a direct connection plug the direct connection leads into the transmitter. Insert the ground stake into the ground a few
meters perpendicular to the line. Connect the black lead to the ground stake. Now take the red lead and connect to the target
line.
