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3 Using the vLoc3-5000
3.2.2 Detecting Radio Signals
1. Locating Radio signals is very similar to detecting Power signals as they are both passive signals.
2. Hold the vLoc3-5000 vertically and away from likely positions of cables or pipes.
3. Adjust the sensitivity control so that the bar graph reading is just starting to show some movement. Now follow the
procedure described above in the Power mode section.
3.3 Active Locating: Applying the 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, signal clamp or
induction (this is further explained in the following sections).
Active locating has the benefit that, unlike passive detecting, the operator is in control of the signals and therefore can be more
specific about what line is detected. That is to say active signals can be used for line tracing. Also, passive signals are not
always present on a line so using active signals ensures more lines are detected.
Choosing the correct frequency will depend on the application but as a general rule, select low frequencies as these tend to “bleed
off” less than higher frequencies. A good general-purpose frequency is 33kHz and is a good starting point if in doubt.
When using “Induction” or the “Signal Clamp”, the frequencies available are limited to a set of frequencies optimised for the
equipment. The full range of frequencies is available in “Direct Connection” mode.
For frequencies below 45 kHz, authorities such as the FCC allow higher power output to be used; for frequencies of 45 kHz and
above, power output for this type of equipment is restricted to 1 watt. Therefore, more power is available when lower frequencies
are used.
To inject a signal requires the use of a transmitter. The signal can be injected, or applied, to the target line in a variety of ways.
3.3.1 Direct Connection
This method involves making an electrical connection to the cable or pipe.
WARNING
When connecting to a cable, only connect to the sheath of that cable. 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.
