INTRODUCTION TO SONAR 



7. Depress marker button. Observe that a 

 straight line is drawn down the full length of 

 the paper. This line should be straight from 

 top to bottom, otherwise the stylus is out of 

 adjustment. 



Security Operation 



If it is not desired to place pulsed energy 

 in the water periodically, the fathometer may 

 be operated as for normal operation, except 

 that the ping switch is triggered downward to 

 SINGLE PING, then is released. The circuitry 

 is arranged to pulse the first time the keying 

 contacts operate after triggering and then re- 

 lease immediately. The ping switch may be held 

 down as long as desired without damage. The 

 result is exactly the same as if this switch 

 were in the AUTOMATIC position. 



Shutdown 



Put the ping switch to the OFF position. 

 Throw the power switch to the OFF position 

 (center). This action disconnects both sides 

 of the 115-volt, 60-cycle supply from the equip- 

 ment (except the service outlet). 



ROUTINE MAINTENANCE 



Routine maintenance as used here applies 

 to fimctions, besides operation, that should be 

 performed by the operator. When the operator 

 checks out fathometer equipment before a run, 

 he should be prepared (if necessary) to make 

 minor adjustments, and replace lamps, tubes, 

 styluses, or paper. Moreover, he should be 

 satisfied that the equipment will render con- 

 tinuous satisfactory performance during the an- 

 ticipated operating interval. 



The manufacturer's technical manual that 

 accompanies the particular fathometer aboard 

 your ship lists a step-by-step procedure for 

 accomplishing minor adjustments, replacing 

 parts, and preventive maintenance requirements. 



TAPE RECORDER 



Sonar Technicians, particularly aboard sub- 

 marines, must be able to make recordings of 

 sonar echoes and of other sounds detected by 

 the transducer or hydrophone. Such recordings 

 are valuable aids in classifying sounds (deter- 

 mining the nature and/or source). All ships 

 and submarines are supplied with the necessary 



equipment to make such recordings. The most 

 common installation is the AN/UNQ-7 recorder- 

 reproducer sound set, familiarly known as a 

 tape recorder. 



The AN/UNQ-7 tape recorder is more sophis- 

 ticated than many commercial types. It is a 

 two-track recorder and reproducer, and is 

 responsive to all frequencies inthe audible range. 

 Both tracks may be recorded either simulta- 

 neously or independently. Normally, track B is 

 used to record signals directly from the sonar 

 equipment. Track A is used for recording voice 

 information. 



When a recording reproduced by the equipment 

 is played back, both tracks can be heard, or only 

 one track, each channel having its own volume 

 control. In short, the AN/UNQ-7 acts as a com- 

 bination of two separate recorders that are 

 capable of being coupled to allow superimposing 

 two audio information channels upon each other. 

 Figure 6-16 shows the front panel of the recorder. 

 Later models, namely the -7B, -7C, and -7D, 

 are transistorized and have a somewhat different 



7.54 

 Figure 6-16, — Tape recorder AN/UNQ-7. 



104 



