A Better Way Of Locating; Getting The Most Out Of Your Sr-20; Advantages Of The Omnidirectional Antenna - RIDGID SeekTech SR-20 Operator's Manual

The SR-20 cannot change the underlying conditions of a
difficult locate, but changing frequency, grounding con-
ditions, transmitter location, or isolating the target line
from a common ground can change the results, by mak-
ing a better ground connection, avoiding signal splits, or
reducing distortion. Other locating receivers will give an in-
dication that they may be over the line but they have
less ability to determine the quality of the locate.
The SR-20 provides more information. If all of the indi-
cators are aligned and in agreement, mark-outs can be
made with more confidence. If the field is distorted it
shows immediately. This allows the operator to do some-
thing to isolate the target line, change the grounding,
connection point, move the transmitter or change the
frequency to get better reception with less distortion. For
extra certainty, take steps to inspect the situation, such as
by requesting potholing.
In the final analysis, there is one "most important" com-
ponent in the locating task – the operator. The SR- 20 pro-
vides an unprecedented amount of information to be
able to make the correct decision rapidly and accurately.

A Better Way of Locating

What the SR-20 Does
The SR-20 is used above ground to sense and trace
electromagnetic fields emitted from underground or hid-
den lines (electrical conductors like metal cables and
pipes) or Sondes (actively transmitting beacons).
When the fields are undistorted, the information from the
sensed fields gives an accurate picture of the buried ob-
ject. When the situation is made complex by interference
from more than one line, or other factors, the SR-20 pro-
vides a display of information that shows multiple mea-
surements of the detected field. This data can make it
easier to understand where the problem is, by providing
clues as to whether a locate is good or bad, questionable
or reliable. Instead of just laying paint in the wrong
place, the operator can see clearly when a difficult locate
needs reevaluation.
The SR-20 provides more of the critical information the op-
erator needs to understand the situation underground.
What It Does Not Do
The SR-20 does not directly detect buried utilities and son-
des. Instead, the SR-20 locates by sensing electromag-
netic fields surrounding conductive objects; it does not
sense the underground objects directly. It provides more
information about the shape, orientation, and direction of
fields than other locators but it does not magically interpret
that information or provide an x-ray image of under-
ground objects.
A distorted, complex field in a noisy environment requires
intelligent human thought to analyze correctly. The SR-20
cannot change the results of a difficult locate, even though
it shows all the information about those results. Using what
the SR-20 shows, a good operator can improve locating
results by "making the circuit better", changing frequency,
grounding or the transmitter's location on the target line.
Advantages of the Omnidirectional
Antenna
Unlike the coils used in many simple locator devices,
the Omnidirectional antenna detects fields on three sep-
arate axes, and can combine these signals into a "picture"
of the apparent strength, orientation, and direction of the
complete field. Omnidirectional antennas offer definite
advantages:
The Mapping Display
The mapping display enabled by the Omnidirectional an-
tennas provides a graphic view of a signal's characteris-
tics and a bird's eye view of the signal from underground.
It is used as a guide for tracing underground cables and
pipes, and can be used to better pinpoint Sondes. It can
also be used to provide more information for complex lo-
cates.
Figure 54 – Mapping Display
The use of lines (representing the signals sensed by
upper and lower antennas) and guidance arrows (point-
ing toward the center of the detected field) combine to
give the locator a graphic picture of the receiver's loca-
tion, and where the target utility or Sonde is. At the
same time the operating screen provides all the infor-
mation needed to understand what is happening with the
field being located – its Signal Strength, continuous dis-
tance, Signal Angle, and proximity to the target. The in-
formation available at one moment on the SR-20 would
take multiple sample readings with some conventional lo-
cators. A distorted or compound field will be easier to in-
terpret when all the information is in a single display as
it is with the SR-20.
Ridge Tool Company
SeekTech SR-20
29