Amprobe ATGC-1 Ground-Coil - Manual (Page 7)

6
� WARNING
If the Receiver does not pick up a signal it does not necessarily mean that the area is safe
for excavating. It is possible that live conductors that do not have current flowing through
them or are not grounded at both ends, do not effectively couple the signal. Extra measures
should be taken to insure that a safety hazard does not exist before any excavating begins.
It is advisable to use the Rechargeable Battery Pack Model B2024 when using the Ground Coil
as it allows a deeper and three times more signal to be induced for longer tracing distances.
Placing the coil directly over the conductor is not recommended, as minimal signal induction
will occur.
TRACING UNdERGRoUNd CoNdUCToRS, WATER pIpES ANd GAS pIpES
Setup
Look around and observe your surroundings. Setup the coil in the area that the conductor 1.
most likely would be buried, approximately 30’ away from where you want to start
identifying the location of the conductor.
Arrange the ATGC-1 Ground Coil in a circle on the ground approximately 3’ from the top
2.
center of the conductor or pipe (Fig. 2). Note: placing the coil directly over the conductor
will not induce any signal.
Plug the ATGC-1 Ground Coil (A) and B2024 Battery Pack (D) into the Transmitter (E).
3.
Set the Transmitter to the “HIGH” MODE and turn the unit “ON”. 4.
At a distance of 25–30 ft from the coil, point the Receiver (C) perpendicular to the ground 5.
with the front label and Signal Strength Indicator facing the coil. If you do not get far
enough away from the coil, the receiver will only pick up the signal radiating through the
air off the coil itself.
Set the Receiver to the “SHORT” MODE and set the Range selector switch to X100
6.
(AT-2000 series only).
Turn the Receiver on by rotating the thumbwheel and set it to 5 (AT-2000 series only). 7.
Finding the Conductor(s)
While maintaining a 25–30 ft radius from the coil, trace the area in a circular pattern, 8.
remembering to keep the Receiver perpendicular to the ground with the front label and
Signal Strength Indicator facing the coils as you are circling the coil (Fig. 3). Individual
short “ghost” signals may be received while moving in this circular direction. This is
normal and due to stray signal current. If you stop moving you will realize that there is
no real signal present. The real signal radiating off the conductor will continually pulse.
Multiple signals may indicate multiple conductors. Locate the area in which the maximum
signal strength is displayed on the conductor you wish to trace
positioning Coil for best signal Induction
When the area of the maximum signal is located, place the Receiver (E) probe tip against 9.
the ground on the centerline (D) of the conductor (F). With the Receiver held in place,
have your partner incrementally adjust the position of the ground coil to the left or right
of its original position to further increase the signal strength displayed on the Receiver.
Adjust the sensitivity down if the Receiver full scale deflects.
Once the coil is positioned to induce the absolute maximum signal. You may turn from
10.
the coil and begin tracing the conductor away from the calibration point, by moving the
receiver back and forth in a pendulum motion, adjusting the sensitivity as necessary. Mark
the ground with paint or chalk where the maximum signal is received.