PINGER-TO- 

 BOTTOM DISTANCE 



Figure R-8. NAVOCEANO scientist using the Mark 15A Precision Depth Recorder to determine pinger-to-bottom 



distance. 



8 clockwise. (See figure R-9a. Tlie Tektronix 

 Model 310A controls are shown.) Set controls 

 1, 2, 3, 9, 10, 11, 12, 13, and 14 as shown in the 

 figure. Adjust controls 15 and 16 to obtain a 

 continuous signal trace across the grid. Adjust 

 controls 4, 5, 6, and 7 for desired positioning, 

 focus, and intensity of the trace. Connect the 

 oscilloscope input "to the PDR phone output, 

 and commence lowering the pinger. 



Step 3. Observe the signal going to the oscil- 

 loscope. Adjust the vertical amplitude dial (1) 

 to obtain a readable trace, and set the Secondary 

 Time/Division dial (9) to .2 seconds. Adjust 

 the Stability dials (15 and 16) until the direct 

 ping is on the zero, 5, and 10 of the scope grid 

 (fig.R-9b). 



Step 4. Determine the pinger-to-bottom 

 distance. As the pinger is lowered, the signal 

 traces on tlie strip chart will either di\'erge or 

 converge, will automatically shift when they 

 reach the edge of the chart, and will cross when 

 the pinger-to-bottom distance is equal to the 

 largest multiple determined in step 1. The 

 traces will continue to diverge and converge 

 as bottom is approached and at each crossing 

 the pinger-to-bottom distance will be less by 

 400 fathoms (fig. R-10). 



Step 5. Continue lowering until the pinger 

 is approximately 100 fms off bottom (when 

 traces are separated by about one-fourth the 

 full scale of the PDR) : then, reduce winch 

 speed and lower the pinger with caution. 



Step 6. When the pinger is approximately 

 20 fms off bottom, stop the winch. From this 

 point, rely mainly on the oscilloscope. 



Step 7. Begin to lower slowly. Turn the 

 Time/Division dial (9) to 5 milliseconds; the 

 unit now is set up to measure pinger-to-bottom 

 distance from 37.5 meters down to 3.8 meters 

 (see table R-2). When the pinger-to-bottom 

 distance decreases to 15 meters, turn the 

 Time/Division dial (9) to 2 milliseconds; the 

 unit then is set up to measure between 15 and 

 1.5 meters. 



Step 8. Continue to monitor the pinger-to- 

 bottom distance, paying out and taking up wire 

 as required until the operation is completed. 



R-9 Maintenance of Pinger. — Should the 

 pinger cease to function during an operation, it 

 should be raised immediately. The pinger may 

 be flooded, the leads may have fouled, or one of 

 the components may have failed. 



Step 1. If flooding is suspected, the unit 

 should be hoisted inboard and drained, by loos- 

 ening the driver lower end cap. Check "O" 

 riiigs for nicks or cuts. 



Step 2. If flooding has taken place, wash the 

 parts with fresh water and dry. 



Step 3. If malfunction of a component 

 caused the trouble, refer to the instruction 

 manual. 



Step 4. If a lead was fouled and disconnected, 

 cover the connection with electrical tape and 

 lower again. 



Step 5. Batteiy voltage should be checked af- 

 ter each lowering. 



Step 6. To bench t€st the driver, connect the 

 output leads across the transformer primary or 

 across a 1-ohm 10-watt resistor. 



R-5 



