Directional drill head beacons for keeping track of pitch, orientation, and depth of the drill head.
https://s3-us-west-1.amazonaws.com/h...s_fullsize.jpg
Previously:
https://www.homemadetools.net/forum/...967#post148950
https://www.homemadetools.net/forum/...173#post138380
https://www.homemadetools.net/forum/...071#post141081
https://www.homemadetools.net/forum/...666#post186214
https://www.homemadetools.net/forum/...055#post153383