Aviation Electronics Technician 1 - Historic Naval Ships Association

Figure 4-17.-Hydrophone and projector.Figure 4-18.-Sonar receiver.indicate the sonar dome azimuth deviation frommagnetic north. The pressure potentiometer providesan output to indicate depth of the dome in water. Theprojector is covered with a black neoprene boot that isfilled with oil.The hydrophone assembly consists of 16 staveassemblies bolted to a cork-lined fiber glass barrel, anend bell, a temperature sensor, and an electronicpackage. The staves, filled with oil and hermeticallysealed, convert the received acoustic pulses tolow-level ac signals. These signals are amplified andapplied through the special purpose electrical cable tothe receiver located in the helicopter. The stavehousings are stainless steel, each containing 12matched ceramic rings with trimming capacitors, andthey are mounted on a printed-circuit board. Theoutput of each stave is applied to a preamplifier,which is on the electronics package. A temperaturesensor for measuring temperature of the water islocated on the end bell.The dome requires no adjustments. All inputs andoutputs are made through the special electricalconnector on top of the electronic housing.4. A dual CURSOR POSITION control forcontrolling the cursor circle on the CRT in bothazimuth and range.5. A three-digit BEARING display that indicatescursor circle bearing in degrees from magnetic north.6. A five-digit RANGE-YARDS display thatindicates the range of the cursor circle in yards.7. An AUDIO switch/indicator for selectingaudio from all eight sectors, or only the sectorselected by the cursor circle position.8. A TARGET switch/indicator for applyingbearing and range information to the pilot’s bearingand range indicator.Sonar TransmitterThe transmitter (fig. 4-19) develops the signals tobe transmitted by the system. A POWER circuitbreaker, located on the front cover of the transmitter,Sonar ReceiverThe sonar receiver (fig. 4-18) consists of allelectronic circuits required for the processing of inputsignals of the sonar set.The following switches and indicators aremounted on the front panel of the receiver:1. A RANGE SCALE-KYDS switch forselecting the desired operating range.2. A MODE switch for selecting the operatingmode of the sonar.3. A FREQUENCY switch for selecting thedesired frequency.Figure 4-19.-Sonar transmitter.4-13