Construction Practice; Further Gpr Knowledge - Sensors & Software CONQUEST 100 User Manual

Conquest 100
Figure 2-13: The shape of the magnetic field generated can be simple or complex depending on whether the wires
are straight, vertically or horizontally oriented, their spacing and the degree of twist.
These factors mean that a deep wire with little current will not be detectable.
PCD can only detect 50 or 60 Hz AC current; it cannot detect wires carrying DC current, like
telephone, alarm and communication wires.
PCD responses in the GPR data don't necessarily come from the ground. Overhead wires or
nearby transformers can appear in the PCD response if the current is high enough.

2.7 Construction Practice

Before starting any work, you should obtain information about any construction practice that can
help in your interpretation of the Conquest results. Remember that construction plans and
drawings are just that: design plans! In construction, the implementation can deviate from the
plan. Do not be surprised when your Conquest results show some differences from your
expectations. This is a common occurrence.

2.8 Further GPR knowledge

While this manual explains operation of your Conquest 100 system, knowing GPR theory and
principles will help in making your scanning successful. Sensors & Software's website
(www.sensoft.ca) contains a wealth of information, case studies and support.
Click here to visit the FAQ (Frequently Asked Questions) page on our website to learn more
topics, such as:
1. Basic GPR Theory
2. How deep can GPR see?
3. What creates GPR Reflections
4. How do I select a GPR frequency?
5. How can velocity be extracted from hyperbolas?
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Principles of Operation