user manual
DEPTH ACCURACY
Depth measurement is a feature of the TW-7700. Accuracy is
defined on an ideal target, that is, one that is continuous, a
good conductor, and not surrounding by other utilities. There are
factors that can cause the operator to question the accuracy
of the utility being traced.
Inductive Transmitter Setup
Inductively, only a small portion of the signal attaches
itself to the utility. With a weakened signal, trace should
be accurate, but depth may not. The conductive method
will yield better results.
Low Receiver Signal Strength
When the signal strength falls below 20 â 25%, depth
readout may not be accurate. It would be beneficial to
move the transmitter to a closer point of contact.
Nearby Utilities
Close, nearby utilities may have some influence on the
accuracy of the Depth readout. This is more prone to
happen in the higher frequencies where signals can jump
to nearby utilities. Switching to a lower frequency can
give better results.
Moisture
Ground that is too dry or overly saturated may skew the
depth readout.
âTâsâ, elbows, or splits in the utility can distort the
transmitted signal in that general area.
9
WARNING: Do not connect output leads to a live
(energized) utility. Please prevent shock hazard and
equipment damage.