® | Locating |
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Field Strength: | Field Strength: | ||||
| 100% |
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| 0% |
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| 0% |
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| 100% | |
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Parallel Field Lines and Antenna | Perpendicular Field Lines and Antenna | ||||
Orientation of Field Lines with Respect to Antennas
Front and Rear
Negative Locate Points
If the field line is vertical with respect to the antennas, each antenna will read 50% of the signal (figure). This occurs at two locations: one behind the transmitter, known as the rear negative locate point (RNLP), and one in front of the transmitter, known as the front negative locate point (FNLP). Each of these locations is a specific point that is independent of the transmitter’s signal strength. Both the rear and front negative locate points are important to accurately locating the transmitter, but the FNLP is used more frequently. The FNLP is also used to aid against oversteering.
>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>
Field Strength:
50% 50%
>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>
Field Strength:
50% 50%
Horizontal Field Lines at PLL
Vertical Field Lines at FNLP and RNLP
Positive Locate Line
Above Transmitter
When the field line is horizontal with respect to the antennas, each antenna will read 50% of the field strength at that point. This location is directly above the transmitter and is referred to as the positive locate line (PLL). The transmitter’s exact lateral location below the PLL can be determined either by using the FNLP and RNLP or by finding the peak signal. However, locating the trans- mitter’s position below ground using the peak signal is not encouraged due to its susceptibility to interference potentials.
DigiTrak® Mark III Operator’s Manual | 55 |