Triplett Fox & Hound 3 – PN: 3397 - Manual (Page 39)

39
to the other wire. Notice that at approximately the midpoint
between the wires, the tracer tone becomes very weak. This
is the “null point” . . . the place where the signal from one
wire cancels the signal from the other wire. Notice how this
null differs from simple loss of signal . . . that is, there’s a
very narrow zone where the null occurs, and the signal gets
stronger quite rapidly on either side of the null. By waving
the HOUND 3 back and forth while slowly moving along the
length of the wire, the path of the null point can be followed
between the wires. These wires can be thought of as being
on either side of the open fault . . . so by using this tech-
nique, it will be possible to localize the area in which the
fault occurs.
TRIPLETT
TONE HI
LO
CONTINUITY TALK
WARBLE
OFF / LINE POLARITY
STRONG
SIGNAL
NULL
SIGNAL
FADES
Figure 7