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3 Using the vLoc3-5000
3.10 Sonde-Location Mode
A Sonde is typically used for locating non-metallic pipes or ducts or the camera end of a sewer inspection camera. Low-
frequency versions (512Hz/640Hz) can transmit through some metallic pipes such as cast iron pipes which is why they are
frequently used with sewer inspection cameras.
The Sonde Location mode is a Peak mode which means that the bar graph and audio will grow when approaching the sonde
and at their maximum when over the sonde.
Sonde screen:
67.2
25dB
2.1m
8kHz
2
2
3
4
5
6
8
7
1
1.
Peak signal detector
2.
Signal strength bar graph
3.
Sonde icon
4.
Null point
5.
Direction to sonde
6.
Frequency selection
7.
Numeric signal level (mirrors the bar graph)
8.
Gain setting
The Sonde transmitting coil radiates differently than that of a line.
Due to this construction the sonde gives a different “Peak” pattern than
when locating a buried utility.
There will be three distinct peaks. A large Peak will be followed by two
smaller Peaks on each side of the large one. A Null point will be between
each small peak and the large peak. The sonde is located under the
center of the “large peak.”
The vLoc3 receivers detect the two “Null” signals and the position of
the main “Large Peak.” It uses this information to provide a reliable and
efficient method of sonde location.
NULL
NULL
MAIN PEAK
The vLoc3 Sonde Screen will display the
Large Peak as a Sonde icon
and the
Null Points as double blue circles
, as shown in the illustration
to the right.
Method
1. Switch on the vLoc3 receiver and use long presses on the Enter key to enter the Sonde screen.
2. Press the “f” key to select the sonde frequency matching the sonde being located.
3. Insert the activated sonde into the pipe. Push the sonde about 10 – 12-feet (3-4m) into the pipe.
4. Hold the locator vertically and stationary with the tip on the ground.
5. When the receiver is within the sondes range a screen similar to the one below will be seen. On the screen, the arrow will
be pointing to the sonde. The bar graphs on either side of the screen are identical and indicate the signal strength. Use the
+ and – keys to alter the receiver gain to keep the signal within the bar graph's limits.
