RIDGID NaviTrack II - Manual (Page 11)

NaviTrack® II
10
Sonde Locating
The NaviTrack® II can be used to locate the signal of a sonde
(transmitter) in a pipe (must be a non-metallic pipe !!), so that
its location can be identified above ground. Sondes can be
placed at a problem point in the pipe using a camera push rod
or cable. They can also be flushed down the pipe.
IMPORTANT! – Signal strength is the key factor in
determining the sonde’s location. To ensure an accurate
locate, take care to maximize the signal strength prior to
marking an area for excavation.
The following assumes that the sonde is in a horizontal pipe,
the ground is approximately level and the NaviTrack® II is
held with the antenna mast vertical.
The field of a sonde is different in form than the circular field
around a long conductor such as a pipe or cable. It is more like
the field around a bar-magnet, with a north pole and a south
pole. Because of differences in the two kinds of fields, the
display in Sonde mode shows signal strength in the upper left
corner, rather than Proximity signal.
In the sonde’s field, the NaviTrack® II will detect the points
at either end where the field lines curve down toward the
vertical, and it will mark these points on the map display with
a “pole” icon ( ). The NaviTrack® II will also show a line at
90 degrees to the sonde, centered between the poles, known
as the “equator”, much like the equator on a map of the Earth.
Figure 16: The Earth’s Dipole Field
To get an idea of a dipole field, imagine the sonde underground
with a field similar to the Earth’s magnetic field, as shown in
Figure 16.
When locating a sonde set up the locate in the following
manner:
• Activate the sonde before putting it in the line.
Select the same frequency on the NaviTrack® II and
make sure it is receiving the signal.
Figure 17: Sonde Frequencies On the Main Menu
•
After the sonde has been sent into the pipe, go to the
suspected sonde location. If the direction of the pipe is
unknown, push the sonde a shorter distance into the
line (~4-5 m from the access is a good starting point).
Location Methods
There are three major parts to locating a sonde. The first
step is to find direction. The second part is homing in on (or
“localizing”) the area of the sonde. The third is completing
the locate by pinpointing its location.
Step 1: Finding the Direction
1. Hold the NaviTrack® II so the antenna mast is pointing
outward. Sweep the antenna mast in the suspected
direction of the sonde while observing the signal
strength and listening to the sound. The signal will
be highest when the antenna mast is pointing in the
direction of the sonde.
2. Lower NaviTrack® II to its normal operating position
(antenna mast vertical) and walk in the direction of the
sonde. Approaching the sonde, the signal strength will
increase and the audio tone will rise in pitch. Use the
signal strength and the sound to maximize the signal.
Ground
Ground
Pole
Equator
Pole
Pole Pole
Equa
tor