Ditch Witch OnGrade - Manual (Page 40)

OnGrade Operator’s Manual
Grade Boring Concepts - 39
Theory of Operation
CMW
Depth Limitation
The depth measurement accuracy of the 8500TK tracker is reduced when the beacon is more than 30’ (9.1
m) below the tracker or 29’ (8.8 m) below the ground surface when tracker is mounted on the grade pole.
For short sections of a bore which are deeper than this, continue drilling using only pitch information until
the depth is less than 29’ (8.8 m).
IMPORTANT: CMW does not recommend using the On-Grade system for installations deeper than 29’
(8.8 m).