JT SONIC LISTENING EQUIPMENT
Description.- Model JT equipment is an improved underwater
directional listening system designed to supplant the Models JP-1, .2,
and 3 equipment, with the following advantages :
Training system characteristics.-The d-c training motor is
supplied by an amplidyne generator, which is controlled by a synchro-servo
system, with an electron tube amplifier. Field current for the training
motor is supplied from the ship's d-c line. A separate synchro system repeats
the hydrophone bearing to remote repeaters at the control console, the
torpedo data computer, and the echo ranging control station.
Power supply.-120 volts, single phase, 60 cycles, and 120 volts d. c.
Tube complement.-16 type 6SJ7, 2 type 6J5, 8 type 6SN7GT, 2 type 6SL7GT, 1 type 6AC7, 3 type 6G6G, 1 type VR15O, 1 type 5U4G, 2 type 6L6, 1 type 991, 1 type 25L6GT/G, 1 type 6E5, 1 type 6H6, 1 type 3-38, 2 type 3-50A.
Hydrophone.-The hydrophone is a straight horizontal 5-foot permanent-magnet magnetostrictive type made up of ten toroidally wound sections, the windings of which are designed to achieve side-lobe reduction.
Receiver specifications.-Signals received by the JT hydrophone
are ordinarily fed to the JT amplifier, the output of which actuates the
headphones, as well as the RLI meter, which indicates whether the signal
was received from the right, left, or on the center line of the hydrophone.
The right-left sense is obtained by separating the signals from the two
halves of the hydrophone; a signal coming from right or left of the hydrophone
normal axis will produce out of phase voltages in the two halves. The phase
difference is used by the RLI system to produce a plus or minus d.c. to
actuate the meter.
Intercommunication system.-The sonar talk-back amplifier
is a separate unit, located near the control station, which permits two
way voice communication between listening operator and conning tower and
also permits the conning tower to listen to the signals being received.
Additional units in the system consist of a conning tower speaker and a
control unit containing switches and phone jacks.
Dimensions and weights Unit Navy Type No. Height Width Depth Weight Inches Inches Inches Pounds Master control unit CRV-23460 38 20 17 233 Sonar talk-back am- CRV-50200 21 17 8 32 plifier. Talk-back control CRV-23461 6 3 5 5 unit. Talk-back speaker CRV-49590 8 8 6 13 unit. Headset assembly COF-49586 8 8 11 2 Motor-dynamo am- CG-21-ACN 12 24 14 190 plifier. Converter amplifier CRV-50199 18 20 14 51 (in cabinet - JP amplifier not in cluded). Hydrophone assembly. CRV-51075 7 65 11 135 (a) Hydrophone CQA-51074 (#1)2 1/2 60 26 (b) Hydrophone CRV-10365 4 65 10 63 baffle. (c)Sound-absorbing CRV-10366 3 10 63 coupler. Power-train mechanism: Mare Island CRV-78241 Portsmouth CRV-78240 CG-211299 Bearing - repeater CRV-24365 11 7 5 8 switch. (#1) Diameter.Literature.-Sonar Sound Receiving Equipment, Navy Model JT NavShips 900,424 (A).
REFERENCES:The information enclosed here is excerpted from:
Catalogue of Naval Electronic Equipment-April 1946- NavShips 900,116.