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Ridge Tool Company
19
When line tracing, it is important to remember that Tees,
curves, other conductors in the vicinity, and nearby
masses of metal can add distortion to the field requiring
closer scrutiny of the data to determine the path of the
target. These distortions are likely to be worse when trac-
ing passively.
For best accuracy, use directly connected Active Line
Tracing whenever possible.
WARNING
In Passive Line tracing, or when signals are ex-
tremely weak, the Measured Depth will generally
read too DEEP and the actual buried depth may be
MUCH shallower.
Operating Tips for Active Line and
Passive Line Tracing
• The NaviTrack II quickly identifies distorted fields. If the
lines are not centered on the map, when the Proximity
Signal or Signal Strength is maximized, distortion is
creating a complex non-circular field. To improve the
tracing circuit:
1.Try changing the frequency used to a lower one.
2.Move the ground stake position away from the line
being traced.
3.Make sure that the line is not commonly bonded to
another utility. Undo common bonds only if safe to
do so.
4. Move the transmitter to a different point on the line,
if possible.
• If the tracing lines will not center or if they move
across the screen erratically, then the NaviTrack II
may not be receiving a clear signal. The Measured
Depth and the Proximity Signal may also be unstable
under these circumstances.
1.Check the transmitter to be sure that it is operating
and well grounded.
2.Test the circuit by pointing the lower antenna at ei-
ther transmitter lead.
3.Check that the NaviTrack II and transmitter are op-
erating on the same frequency.
4.Try different frequencies, starting with the lowest,
until the line can be picked up dependably.
5.Re-locate the ground connection for a better cir-
cuit. Ensure there is enough contact (ground stake
is sufficiently deep) especially in dryer soils. When
soil is dry, soak the earth around the ground stake to
improve signal.
• Using the Signal Angle Indicator is another way to
check for distorted signals. Move the NaviTrack II
perpendicularly to both sides of the traced line until the
Signal Angle Indicator reads 45 degrees. Be sure to
keep the lower Omnidirectional antenna node at the
same height and the locator level. If there is little or no
distortion the traced line should be in the middle and
the distance to each 45 degree point should be ap-
proximately the same on either side.
Another variation of this technique is to move the same
distance to the right and left of the traced line, say 24
inches (60 cm) and check that the Signal Strength read-
ings are similar.
Figure 30 – Checking for Distortion
• While tracing, the Proximity Signal and Signal Strength
should maximize, and the Measured Depth should
minimize at the same place where the lines center
on the display. If this is not the case, the utility may be
changing direction or other coupled signals may be pre-
sent.
• Higher frequencies bleed over to adjacent utilities more
readily, but may be needed to jump breaks in tracer
wires or go over insulating couplers. If the line is un-
grounded at the far end, higher frequencies may be the
only means to make the line visible
(See on page 28).
• When using the transmitter inductively, be sure to
begin the locate about 30 feet (10m) away to avoid “di-
rect coupling”, also known as air coupling. This occurs
when the NaviTrack II picks up the signal from the
NaviTrack
®
II
Same Distance
45° Point
45° Point
Energized Pipe