Chapter 6— PRINCIPLES OF SONAR 



P 



I -v THROW TO ON AND WAIT 30 SECONDS , 

 ' OR THROW TO STANDBY IF INSTANTANEOUS 

 OPERATION MAY BE REQUIRED IMMINENTLY 



/pN SELECT INDICATOR OR RECORDER AND 

 V^PROPER DEPTH RANGE 



©SELECT AUTOMATIC OR SINGLE 

 PING 



'A\ ADJUST GAIN CONTROL TO GET 

 ■^^ A GOOD ECHO 



HEADPHONE/MARKER 



ITOWflTlC 



RAWGE 



5> 



<S» 



ADJUST ILLUMINATION 

 CONTROL TO SUIT 

 SURROUNDINGS 



USETO MARK VERTICAL LINE ON 

 RECORDER CHART FOR TIME 

 IDENTIFICATION 



Figure 6-15.- 



71.58 

 ■Fathometer control panel. 



fathometer. Deviations may be considered as 

 expedients for conservingelectrical energy, time, 

 paper, or for maintaining sonar security. 



1. Move power switch to STANDBY, wait 

 about 30 seconds, then throw the switch to ON. 

 This procedure prolongs the life of the Iceyer 

 tube by allowing the filament to heat before 

 applying plate voltage. 



2. On the range switch select the proper 

 range scale. On the indicator the scale is either 



100 feet or 100 fathoms. On the recorder the 

 scale is 600 feet, 600 fathoms, or 6000 fathoms. 



3. Set the ping switch to AUTOMATIC. 



4. Turn the gain control clockwise imtil a 

 suitable echo mark is obtained. 



5. Observe that both styluses attached to 

 the revolving belt mark the paper from the 

 zero line to 5 feet. 



6. Check to see that the proper range mark- 

 ing is indicated on the top of the paper. 



103 



