D. SEISMIC PROFILER (cont'd) 



6. Transducers: 



Type: Transmitter: Sparker; Receiver: wideband omnidirec- 

 tional, or at times directional, hydrophone 



Location: Both transducers are towed 10 to 20 feet apart 

 aft of the ship at a depth of 3 to 5 feet and a speed of 4 

 to 6 knots. The transducers can be hull-mounted if the 

 ship is sufficiently quiet. 



Transmitter life: About 7 hours 



"2 



7. Acoustic power: Sparker: 1.3 x 10 watts (calculated from a 



measured value of 100 db above a microbar) 



8. Acoustic frequency: 



Approximate range: 30 c.p.s. to 10 kilocycles 

 Peak: 300 to 600 c.p.s. 



9. Acoustic pulse length: 0.1 to 0.2 millisecond, (A bubble pulse 



of about 4 milliseconds is associated with the discharge 

 pulse.) 



10. Acoustic pulse repetition rate: 2 to 4 pulses per second (normal), 

 20 pulses per second (maximum) 



11. Receiver band pass filter network: Adjustable 



High pass: 75 c.p.s. 

 Low pass: 10 kilocycles 



12. Graphic record: 



Scale: to 20, 40, 50, 100, 150, 200, 300, 400, 500, 1,000, 



1,500, and 3,000 fathoms 

 Paper type: Wet, electrosensitive (Alfax A) 

 Paper dynamic range: About 20 db 



13. Net weight: About 1,000 pounds (excluding recorder) 



14. Relay rack (19 inches wide) panel space: 120 inches (one 72- 



inch panel and one 48-inch panel) 



15. A. C. power consumption: Not known, except that a 5-kilovolt- 



ampere source is sufficient 



D-7 



