The sonar control room or "sound hut" houses the sonar equipment for the SLATER. Its location near the flying bridge places it in close proximity to the command and control area of the ship.
For display purposes, the SLATER currently has a WWII era QJB Console in the sound hut located on the starboard side, and a post-war SQS-4 unit located on the port side. The equipment located in the sound hut is mounted as close to the wheelhouse as feasible to permit rapid communication between the operator of this equipment, the operator of the tactical range recorder and the Conning Officer. During WWII, the principal pieces of equipment would have been a "Q" series sonar stack, the tactical range recorder or chemical recorder as it was known and a MK1 attack plotter. Before the advent of CIC, a bulkhead mounted dead reckoning tracer or DRT was located here. WWII sonar had no visual presentation and the operator relied on sound to determine the direction and distance to a submarine. Supporting sound equipment, including the retractable transducer-receiver, is located in the lower sound room, which is located forward and just above the ship's keel. WWII era sonar was searchlight sonar that had to be manually moved in bearing as it was used.
Post-war sonar, such as the SQS-4, was omni-directional, scanning out in all directions automatically. When the SLATER received more modern sonar while in Greek service, the sonar control room was relocated to a compartment below the mess decks on the starboard side and a non-retractable sonar dome was installed nearby.
The model QJB is a searchlight type sonar equipment intended for installation in destroyers and destroyer escort vessels. This equipment is smaller than the QGB, and all its electronic units are housed in a single console. The QJB transmitter is much smaller than the QGB transmitter because of the lower power requirements of the QJB. Although the transmitted power is less, the resultant echoes are equal to those of the QGB due to the higher sensitivity of the crystal transducer of the QJB. The transmitter is mounted in the lower right section of the console. The other units in this console are the receiver, keying unit, bearing deviation indicator, indicating range recorder, remote training control, and power supplies.
The receiver is of the sum and difference type and has both time-varied-gain (TVG) and reverberation-controlled-gain (RCG) features.
The QJB utilizes the unicontrol-oscillator system for tuning the receiver and transmitter. The operating frequency need not be tuned carefully to the frequency of the crystal transducer because the transducer has a rather flat resonance curve-about 6 Kc wide.
The chief difference in the appearance of the QJB console as compared with the QGB is the manner in which the BDI cathode-ray tube is mounted. The QJB mounting is shown in figure 2. The tube is located in the center of the bearing circle so that the operator does not have to shift his eyes away from the bezel indicating the transducer bearing when he wishes to see the BDI indications. To mount the BDI cathode-ray tube in the center of the bearing indicator-which consists of a true-bearing circle and a bezel ring that indicates the transducer bearing-a complicated mechanical system is required.