i5000 Receiver - Operations Manual
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4.4.1 Signal Select
The direction of the signal in the targeted line is determined by analyzing the sign of the
demodulated Signal Select signal. When the receiver is positioned over a signal that carries an
inverted field (i.e., one in which the phase is –180° from the expected, the Guidance Compass
points down, as shown below for a line that is bonded to the target line and carries return current.
Figure 4-7 Signal Select Sample Scenario
An example of how the Distortion Alert feature acts as a warning about situations that (using
traditional methods) appear to be quite ordinary can be seen below. In this case, there is
significant bleedover from the target line to a shallower line, with the current running in the same
direction forward in both lines. Since the bleedover line is shallower, its effect diminishes as the
receiver is positioned farther to the right or left. Thus the red filling is at a lower level in the
Guidance Compass in these areas. The measured distortion approaches a peak about in the
same place as the signal strength peak, indicating the presence of another conductor.
Figure 4-8 Distortion Alert Sample Scenario
In this particular case, the centerline estimate is not significantly biased, though the depth
estimate is less accurate.
