Aviation Electronics Technician 1 - Historic Naval Ships Association

select which signal goes to which pen on the recorder.The MAD AUX POWER-OFF switch suppliesprimary ac power to the SAD system and the selectorcontrol subassembly. The INHIBIT light indicates aninhibit signal from the SAD system.MX-8109/ASA-71 SELECTOR CONTROLSUBASSEMBLY.— The MAD signals from theMAD control and the SAD mark from the MAG VARindicator are routed to this subassembly. The selectorcontrol panel selects which one goes to which pen,and the subassembly routes the signal to the properpen. A SAD mark 1-kHz tone is generated by thesubassembly to be supplied to the ICS system for theSENSOR operator.RO-32 MAD RecorderThe RO-32 recorder makes a hardcopy of MADcontacts and SAD marks. This recorder has twostyluses, one black and one red, to differentiatebetween the two. The chart drive is removable toenable the operator to remove and replace the papertape. here are three knobs on the faceplate. The firstswitch is the ON/OFF switch. The second controlsthe intensity of the internal lights. The third knobselects the operate mode along with the pencalibration modes.When B is selected on the mode knob, the blackpen should trace along the zero line on the paper tape.When the mode knob is switched to the +, the blackpen should go to +4. When this knob is switched tothe R position, the red pen traces along the zero line.When it goes to the +, the red pen should swing to the+4 line. Both pens are adjustable to these settings.SONOBUOYSLearning Objective: Recognize theclassifications and the operating principlesof sonobuoys currently in use.The detection, localization, and identification ofsubmarines is the primary mission of the Navy’sairborne ASW forces. The ability of the Navy tocomplete this mission is dependent upon thesonobuoy. The sonobuoy has undergone a great dealof change in the past 25 years. These improvementshave provided the fleet with large numbers of veryreliable sonobuoys that perform various missions.OPERATING PRINCIPLESThe sonobuoys are dropped from the aircraft intoan area of the ocean thought to contain a submarine.The pattern in which the sonobuoys are droppedusually involve three or more buoys.The sonobuoys detect underwater sounds, such assubmarine noise and fish sounds. These soundsmodulate an oscillator in the RF transmitter portion ofthe sonobuoy. The output of the transmitter is afrequency modulated VHF signal that is transmittedfrom the antenna. The signal is received by theaircraft, and then detected and processed by asonobuoy receiver. By analyzing the detected sounds,the ASW operator can determine variouscharacteristics of the detected submarine. The use ofseveral sonobuoys operating on different VHFfrequencies in a tactical pattern enables the ASWoperator to localize, track, and classify a submergedsubmarine.Each sonobuoy type is designed to meet a specificset of specifications that is unique to that particularsonobuoy. Even though different manufacturers, thespecifications and operational performancecharacteristics are the same for all manufacturers.There are differences in the methods used forprelaunch selection of life and depth settings from onemanufacturer to another for the same sonobuoy types.These differences are found in the SonobuoyInstruction Manual, NAVAIR 28-SSQ-500-1. Youshould refer to this manual prior to storing, handling,or disposing of sonobuoys.Sonobuoy Frequency ChannelsCertain sonobuoy designs are equipped with anelectronic function select (EFS) system. The EFSsystem provides each sonobuoy with a selectable99-channel capability. EFS also provides eachsonobuoy with 50 life and 50 depth setting selections.The operator must reset all three settings any time anyof the three are changed.With the older type of sonobuoy, the transmitterfrequency is preset at the factory. here were 31different channels used within the 162.25- to173.5-MHz band. Transmitter frequency is designedto be within ±25 kHz. temperature extremes in hot orcold storage adversely affect these tolerances,especially in sonobuoys that are older.4-24