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(b) Oscilloscope grid showing direct ping at 0, 5, 

 and 10. 



(a) Diagram of oscilloscope panel 



(c) Oscilloscope grid, showing direct ping at and 

 reflected ping at 6. (With dial (9) set at 5 milli- 

 seconds, pinger-to-bottom distance is 23 meters. With 

 dial (9) set at 2 milliseconds, distance is 9 meters.) 



Figure B-9. Oscilloscope monitoring of pinger-to-bottom distance. 



R-6 



