Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4909336 | Drill steering in high magnetic interference areas | David C. Brown | 1990-03-20 |
| 4593559 | Apparatus and method to communicate bidirectional information in a borehole | David C. Brown, Harold J. Engebretson | 1986-06-10 |
| 4459760 | Apparatus and method to communicate information in a borehole | Donald H. Van Steenwyk | 1984-07-17 |