Locating Principles
How electromagnetic locating works
Voltage is placed on a metallic utility by a transmitter. This voltage produces an alternating current. Current travels in two directions on both the utility and through the earth.
A product of this current flow is a field detectable at the earth’s surface.
The field is detected by a coiled receiving antenna.
Alternating current can be applied using a variety of frequencies.
Without current, no field exists.
A coiled-antenna can be positioned in one of two optimized-response positions: peak and null.
The simultaneous use of multiple coiled-antennas within the field provides information beyond lateral location, such as utility depth estimation.
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