Sonde Locating - RIDGID SeekTech SR-60 Manual

Operating Tips for Passive Line Tracing
1. In Passive Locating if you are looking for a known line, be
sure you are using the best frequency for the line in ques-
tion. This may be, for example, 50/60 Hz (1) for a power line,
or it may turn out that 50/60 Hz (9) produces a more reliable
response on a particular line.
2. If seeking a cathode-protected pipe in Passive Mode, use
higher-frequency (greater than 4 kHz) to pick up har mo-
nics.
3. Remember that pipes can carry currents that will show up
on a Passive Trace as well as cables will; the only guarantee
of a locate is exposure and visual inspection.
4. In general, Passive Trace locating is less reliable than Active
Line Tracing because Active Line Tracing offers the positive
identification of the signal from the transmitter.
5. Especially in Passive Line Tracing, knowing that you have
found something is not the same as knowing what you
have found. It is essential to use all the indicators available,
such as Measured Depth, Signal Strength, etc., to confirm a
locate. If it is possible to access part of a passively-located
cable, it can then be energized using a transmitter and posi-
tively traced.
6. While Passive Line Trace is most often used on 50/60 Hz
power lines, other cables such as phone lines, CATV lines,
etc., can be energized in operation, or by transient radio
frequencies in the region and may appear on Passive Line
Trace searches.
7. Verify a passive locate by finding a known termination point
and hooking up a transmitter to it to do an active locate on
the line, if this is possible.

Sonde Locating

The SR-60 can be used to locate the signal of a Sonde (transmit-
ter) in a 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. A Sonde is often used for locating non-conducting pipe
and conduit.
Signal strength is the key factor in determining the
Sonde's location. Take care to maximize the Signal
Strength prior to marking an area for excavation.
The following assumes that the Sonde is in a horizon-
tal pipe, the ground is approximately level and the
SR-60 is held with the antenna mast vertical.
The field of a Sonde is different in form from the circular field
around a long conductor such as a pipe or cable. It is a dipole
field like the field around the Earth, with a north Pole and a south
Pole.
In the Sonde's field, the SR-60 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 SR-60 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 if the planet were viewed side-
ways (See figure 33).
Note that because of the SR-60's Omnidirectional antennas, the
signal stays stable regardless of orientation. This means the sig-
nal will increase smoothly when approaching the Sonde, and de-
crease smoothly moving away.
Note: A Pole is found where field lines turn vertical. The
Equator occurs when the field lines are horizontal.
Ridge Tool Company
SeekTech SR-60
IMPORTANT!
Figure 33: Earth's Dipole Field
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