Theory of Locating -
C
able Locators consist of a transmitter and a receiver. In the
case of the Pro800, the transmitter is the long black box and the wand is yellow and
black. In operation, a transmitter places a specific frequency signal onto the metallic
conductor you are trying to trace. This placing of an AC signal onto a cable produces an
electrical current and an electromagnetic field around that cable. If the wand is close
enough, this signal is received and amplified by the wand.
It is very important to understand that the circuit you are creating follows the laws of
physics and electricity. A cable transmitter creates an electrical current (AC) that travels
down the cable, through grounding to the earth, and then back to the transmitter through
the ground stake. The tracing signal will always travel on the path of least resistance. If
there is too much resistance or no circuit path, no current will flow and no locate will be
possible. So keep in mind that when a signal is heard, it is because the signal has a
complete path that is creating an electrically friendly way for the signal to travel back to
the transmitter. The signal doesn't just randomly wander through the dirt. It follows a
path provided for it, whether it is a pipe, wire, reinforcing bar. etc.
It is also important to note that in the tracing circuits, a return path needs to be present.
Basically, the return path completes the circuit. In most cases, this will be the earth
ground as the signal transmits down the cable and returns to the ground stake.
However, any return is possible, so a common wire could work. Or if you have a looped
wire, like a dog fence, the loop itself returns to the start and therefore provides a 'ground'
instead of the ground stake. You don't have to use a ground stake but you do have to
give the signal a way to return to the transmitter.
Battery
-
The Pro800 transmitter comes with a 12 volt rechargeable battery, located
inside the battery compartment.
