Product Manual
11
HIGH POWER (with handle)
An interesting phenomenon on the TW-6 compared to the TW-5
and an earlier model is that you may prefer to use it in HIGH power,
on-the-handle. The Sensitivity knob will need to be lowered to
about 3 or slightly less to get the meter reading down to zero and
no sound when balancing. As you approach a pipe or cable lying
beneath the ground, the signal may be slight, approximately 20
to 30 and it can be difcult to identify the peak.
Now turn the Sensitivity knob up so the meter reading becomes
70-75. As you move forward and backward, you will easily see
a peak on the meter. Mark the spot on the ground where you
have stopped, with both feet together. Then go on beyond the
conductor, turn around and approach the conductor in the same
way, stopping with feet together at the highest meter reading and
mark the spot on the ground. Measure between the two points,
bisect it and you have the centerline of the conductor.
Be aware that when you use HIGH power on the handle, you will
need to be further away from vehicles, metal buildings and metal
fences to avoid sensing them as well.
MODES OF OPERATION
14
DETERMININING CONDUCTOR DEPTH BY TRIANGULATION
This procedure is only accomplished when the transmitter is close
enough for the receiver to receive a strong and clear signal.
Once you have determined the exact centerline of the conductor
(either Inductively or Conductively), place the receiver above and
parallel to it. Hold the receiver as close to the ground as possible.
Now, tip the receiver back until the bubble inside the depth level
indicator rests between the outer edge of the center ring and the
black border of the level.
When it does, the receiver will be at a 45-degree angle to the level
ground. Care should be taken at this point, as a few degrees of
deviation will affect the nal depth analysis. The operator should
be holding the receiver at 45 degrees and facing toward the
conductor centerline. Now, back away slowly, at a right angle
to the conductor, keeping the bubble as steady as possible. The
meter indication should manually be adjusted by means of the
sensitivity control to stay on scale in order to observe the point
where the needle will fall to a minimum signal. After this point, the
signal begins to increase again.
Position the receiver at the minimum or null point. Measure the
horizontal distance from the centerline of the conductor to center
of the fastener, which holds transmitter and receiver together. This
distance, minus the distance of the center of the locator loop
above the ground distance (5”) is the depth of the conductor.
If the conductor is buried in sloping ground, make a depth
determination on each side of the conductor and average the
two distances to nd the cable depth.
A tracer probe with its smaller receiver coil in the tip, is quicker
and easier to use, hence it yields greater accuracy in depth
nding and tracing. The same principle of triangulation is used
when using the receiver or receiver with tracer probe.
MODES OF OPERATION