Current And Signal Angle Reading; Passive Line Tracing - RIDGID SeekTech SR-20 Operator's Manual

SeekTech SR-20
Current Strength
vices that are connected to AC power will radiate a certain
amount of electronic "noise" back onto the power lines
they are connected to. Examples of such devices in-
clude computers, copy machines, refrigerators, anything
with an electric motor, TV sets, air conditioning units etc.
Another common way electromagnetic noise can get
onto the line is by way of induction that can operate with-
out any direct physical connection to the buried line. In
some areas for example, buried utilities act as anten-
nas for high powered, low frequency radio transmissions
(submarine navigational and communication signals in the
UK for example) and will reradiate these signals. These
reradiated signals can be very useful for locating.
Similarly, buried lines that run side by side near each
other, particularly for longer distances will tend to bleed
signals onto each other. This effect is more pronounced
for higher frequencies. Due to coupling (either through in-
duction or through capacitance), all metallic lines in an
area may be energized. Because of this, it is possible to
locate lines passively, but it is difficult to identify which
line the locator is tracing.
1. Select a Passive Line Trace Frequency (
icon).
16
Current Strength
Figure 24 – Screen Display in Different Locations (Line Tracing)
or
Ridge Tool Company
Figure 25 – 60 (9th) Hz Passive Trace Frequency
2. The SR-20 has multiple Passive Line Trace fre-
quency settings. Power frequencies (identified with
the power icon ) are used to locate signals generated
as the result of power transmissions, usually 50 or 60
Hz. To reduce the effects of inherent noise from line-
load or neighboring devices the SR-20 can be set to
locate various multiples (or harmonics) of the base
50/60 Hz frequency up to 4,000 Hz.
2. The 9x multiple is the setting most commonly used to
locate 50/60 Hz signal. In well balanced high voltage
electric distribution systems, the 5x multiple may
Signal Angle