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® | Locating |
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4.Step further to the side of the transmitter and again find the point where the
5.Repeat this procedure to find the third location (Point 3).
When all three of these points are lined up, they confirm the location of the PLL, from which the heading of the transmitter can be determined, because the PLL is at a 90° angle to the transmitter. As drilling continues, the drill should be steered to maintain constant slant distances at either of Points 1, 2, or 3. If the slant distance increases, the transmitter is moving away. If the slant distance decreases, the trans- mitter is moving toward the side position.
Splitting the Front and Rear Negative Locate Points
At increased depths, a phenomenon occurs whereby the fine tuning of the FNLP and RNLP (when the receiver is held perpendicular) results in a range or distance between the FNLP (or RNLP) which requires you to “split” this range or distance for the true FNLP (or RNLP).
For instance, find the FNLP by walking out in front of the transmitter (your back is towards the drill). Now turn perpendicular so your left shoulder faces the drill. With the trigger held in continue to walk towards the left side of the drill string, note that the
Four-Turn Technique
The
To find the FNLP or the RNLP:
1.Be sure the transmitter is awake and the receiver has completed its
2.Hold in the trigger and rotate the receiver around the plumb line axis point (see the “Using Depth Antenna Plumb Line to Mark Locate Points” in the Receiver Section) until you see a “+” sign in the top left window.
3.Walk in the direction the receiver is facing when the “+” sign is found (keeping the trigger held in) until the “+” sign changes to a
4.Turn the receiver 90° to the left.
5.You will see either a “+” sign or a
6.When the “+” sign changes to a
DigiTrak® Mark III Operator’s Manual | 51 |