User's Manual

Appendix B
DigiTrak
®
SE™ Operator’s Manual 69
The locate points (FLP and RLP) are also shown in Figure B2. These points are located at the vertical
components of the signal field, as illustrated with short vertical yellow lines in the figure above. Note that
the locate points are not the same distance from the LL when the transmitter is pitched. Again, this
situation requires compensation for the projected depth and the fore/aft offset.
Using the tables provided below, you can look up the actual depth (Table B1) and the fore/aft offset
(Table B2) based on the receiver’s depth reading (projected depth) and the transmitter pitch. You can
also look up the projected depth (Table B3) if you know the required depth (actual depth) of your instal-
lation and you want to find the corresponding projected depth reading that you will see on the receiver
during drilling. The final table (Table B4) provides conversion factors for determining the projected depth
from the actual depth or the actual depth from the projected depth at various transmitter pitches.
Table B1 lists the projected or displayed depth values (shown in red) in 5 ft (1.52 m) increments in the
first column and provides values for the actual depth (shown in green) at different transmitter pitches. For
example, if you have a displayed depth of 25 ft (7.62 m) and your transmitter is at a 40% (22°) pitch, then
you can see from Table B1 that the actual depth of the transmitter is 22 ft 8 in. (6.91 m).
Table B1. Determining Actual Depth from Displayed (Projected) Depth and Pitch
Pitch→
Displayed
Depth ↓
±10%
(5.7°)
±20%
(11°)
±30%
(17°)
±40%
(22°)
±50%
(27°)
±60%
(31°)
±75%
(37°)
±90%
(42°)
±100%
(45°)
5'
(1.52 m)
5'
(1.52 m)
4' 11"
(1.50 m)
4' 9"
(1.45 m)
4' 6"
(1.37 m)
4' 4"
(1.32 m)
4' 2"
(1.27 m)
3' 10"
(1.17 m)
3' 6"
(1.07 m)
2' 6"
(0.76 m)
10'
(3.05 m)
9' 11"
(3.02 m)
9' 9"
(2.97 m)
9' 5"
(2.87 m)
9' 1"
(2.77 m)
8' 8"
(2.64 m)
8' 3"
(2.51 m)
7' 7"
(2.31 m)
7'
(2.13 m)
5'
(1.52 m)
15'
(4.57 m)
14' 11"
(4.55 m)
14' 8"
(4.47 m)
14' 2"
(4.32 m)
13' 7"
(4.14 m)
13'
(3.96 m)
12' 5"
(3.78 m)
11' 5"
(3.48 m)
10' 6"
(3.20 m)
7' 6"
(2.29 m)
20'
(6.10 m)
19' 11"
(6.07 m)
19' 6"
(5.94 m)
18' 10"
(5.74 m)
18' 1"
(5.51 m)
17' 4"
(5.28 m)
16' 6"
(5.03 m)
15' 3"
(4.65 m)
14'
(4.27 m)
10'
(3.05 m)
25'
(7.62 m)
24' 11"
(7.59 m)
24' 5"
(7.44 m)
23' 7"
(7.19 m)
22' 8"
(6.91 m)
21' 8"
(6.60 m)
20' 8"
(6.30 m)
19'
(5.79 m)
17' 6"
(5.33 m)
12' 6"
(3.81 m)
30'
(9.14 m)
29' 10"
(9.09 m)
29' 3"
(8.92 m)
28' 3"
(8.61 m)
27' 2"
(8.28 m)
26'
(7.92 m)
24' 9"
(7.54 m)
22' 10"
(6.96 m)
21'
(6.40 m)
15'
(4.57 m)
35'
(10.67 m)
34' 10"
(10.62 m)
34' 2"
(10.41 m)
33' 1"
(10.08 m)
31' 8"
(9.65 m)
30' 4"
(9.25 m)
28' 11"
(8.81 m)
26' 8"
(8.13 m)
24' 6"
(7.47 m)
17' 6"
(5.33 m)
40'
(12.19 m)
39' 10"
(12.14 m)
39'
(11.89 m)
37' 9"
(11.51 m)
36' 2"
(11.02 m)
34' 8"
(10.57 m)
33'
(10.06 m)
30' 5"
(9.27 m)
28'
(8.53 m)
20'
(6.10 m)
45'
(13.72 m)
44' 9"
(13.64 m)
43' 11"
(13.39 m)
42' 5"
(12.93 m)
40' 9"
(12.42 m)
39'
(11.89 m)
37' 2"
(11.33 m)
34' 3"
(10.44 m)
31' 7"
(9.63 m)
22' 6"
(6.86 m)
50'
(15.24 m)
49' 9"
(15.16 m)
48' 9"
(14.86 m)
47' 2"
(14.38 m)
45' 3"
(13.79 m)
43' 4"
(13.21 m)
41' 3"
(12.57 m)
38' 1"
(11.61 m)
35' 1"
(10.69 m)
25'
(7.62 m)
Table B2 lists the projected or displayed depth values in 5 ft (1.52 m) increments in the first column and
provides values for the fore/aft offset (shown in purple), rounded to the nearest inch (or cm) at different
transmitter pitches.