Product Manual

7
MODES OF OPERATION
Your Fisher Model TW-6 allows two modes of operation: INDUCTIVE
and CONDUCTIVE. In the INDUCTIVE mode, the Transmitter
induces the electromagnetic eld around the object sought.
The Transmitter radiates this eld through both soil and water.
INDUCTIVE is subdivided into two modes: (1) On the handle for
LOCATING and (2) Transmitter placed on the ground directly
above and in line with the conductor for TRACING and the path
of the conductor.
The CONDUCTIVE mode operates when you connect the
Transmitter directly to an exposed portion of the pipe or cable in
question with the Ground Plate Assembly, or with the Coupling
Clamp, or the Ground Rod Assembly.
THE INDUCTIVE MODE
HOW TO ASSEMBLE
1. If you have the 3-piece handle, insert the two
end sections into the central section and turn the
knobs until they are “nger-tight”.
2. Place the Transmitter on its back and insert
handle end with one screw into V-shaped slot.
3. Turn the knob until it is “nger-tight”.
18
TRACING PROCEDURE
Turn the transmitter ON and turn receiver SENSITIVITY knob all the
way up in NORMAL. Then, when the conductor is located, turn
SENSITIVITY down to get a precise indication of the location. Use
NORMAL for ordinary tracing, HIGH for extended tracing. In the
Conductive Mode, you can have Transmitter and
Receiver as near to each other as 20 feet apart and closer yet
if you use the Tracer Probe, without air coupling occurring. With
HIGH power, the distance increases.
With settings and connections completed, the operator need only
walk out his trace while paying attention to signal strength over
the conductor. As in the Inductive Mode, the receiver should be
carried vertically and parallel to the pipe or cable being traced.
However, once the position is discovered, you may turn the
receiver to a horizontal position to get a pinpoint reading.
If you’re dealing with a maze of pipes, trace each line and mark
its surface location on pavement with colored chalk or spray paint
as you locate it. Extra long yellow or white golf tees are very handy
markers when locating over turf or open ground.
Another tip...start tracing operations away from the congested
location. The pipe is then carefully traced into the desired area
with little chance of false indications. The Tracer Probe also helps
reduce spurious signals from nearby pipes and cables.
The Tracer Probe
As you trace out the pipe or cable, signal strength gradually
diminishes. When you reach the limit of NORMAL, switch to HIGH
sensitivity and adjust the sensitivity knob for a sharp null over the
conductor you are following.
The tracer probe designed especially for the TW-6 is slightly shorter
than the earlier model and does not need a separate SENSITIVITY
knob. It can be used effectively with the earlier TW-5 model. The
Tracer Probe for the TW-5 can be used with the TW-6 but reduces
tracing distance.
Once you have located the pipe or cable with a sharp “null”,
back away at right angles, dragging the tip of the Tracer Probe
on the ground and maintaining the level bubble centered in its