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WCA, WCA-1 ECHO RANGING LISTENING AND SOUNDING EQUIPMENT

Use.-Fleet submarines.

Contract number. -NOs-82337.

Description.-Model WCA and WCA-1 equipments combine in one system two separate ranging/listening equipments and a sounding equipment. The two models are essentially the same, differing principally only in their power requirements. A complete installation includes two ranging/listening projectors, one Rochelle salt and one magnetostrictive, mounted port and starboard on the boat; a sounding projector; two drivers, one of which is used alternately for ranging or sounding; and four receivers. The ranging/listening projectors are trained independently.
A field modification to the equipment permits it to be used for mine and torpedo detection.

Keying interval.-Ranging-5,000 yards and manual. Sounding-400, 800, 2,000, and 4,000 fathoms.

Maintenance of true bearing.-No.

Maintenance of close contact.-No.

Bearing deviation indicator.-No.

Tuning.-Magnetostrictive system, receivers and driver separate; Rochelle salt system, receiver and driver unicontrolled.

Range indication.-Revolving disc.

Sweep frequency modulation.-Yes; on Rochelle salt system.

Hoist-lower system characteristics.-Theranging/listening projectors are spherical in shape, and may be retracted into sea chests in the hull. In some installations a nonretractable streamlined dome is welded to the hull around one of the projectors, in order to permit operation at higher speeds than would be possible with the unstreamlined sphere. The hoist mechanism is hydraulic, and is not supplied by the contractor but is constructed by the building yard.

Training system characteristics.-Training is electrical, remotely controlled by a d. c. system. A motor generator set supplies the voltage to operate the training motor, the magnitude and polarity of the voltage being regulated by a lever switch at the remote control station which controls the generator field. Limit switches and positive stops restrict training to an arc of 1020 degrees. Slip rings for the projector connections are included in the MATD modification, permitting unlimited training in either direction. Projector bearing is repeated to the control stack by a synchro system.

Power requirements.-WCA-175-335 volts d. c., 6.6 kw. WCA-1-90-150 volts d. c., 6.6 kw.

Tube complement.-9 type 6C6, 13 type 6D6, 8 type 41, 6 type 76, 3 type 874, 4 type 5Z3, 1 type Argon CD 22 CL, 4 type 807, 4 type 838, 3 type 6J5, 4 type 6AB7, 2 type 836, 3 type 5U4G, 3 type 6A6.

Projectors.-Three projectors are used, designated respectively "QC-JK" (ranging/listening); "QB" (ranging/listening) ; and "NM" (sounding).
QC-JK: Combination type, two elements, mounted back to back in a spherical housing.
QC: Magnetostrictive, electrically polarized (from MG set), resonant frequency 24 kc.
JK: Rochelle salt, 14 to 32 kc.
QB: Rochelle salt, 14 to 32 kc.
NM: Magnetostrictive, electrically polarized (from MG set), resonant frequency 24 kc.

Transmitting system.-Two drivers are supplied with each equipment, one for the magnetostrictive projectors, either ranging or sounding, the other for the Rochelle salt (QB) ranging projector.
QC/NM driver-The electron tube oscillator is tunable over the range from 22.5 to 25.5 kc; its output is fed to a four tube push-pull parallel amplifier section. The high voltage plate supply is provided by a high voltage section of the equipment MG set.
QB driver-The QB driver contains a fixed frequency electron tube oscillator operating at 60 kc. Its output is mixed with that of the receiver variable oscillator to produce the 14 to 32 kc transmitted frequency; unicontrol of receiver and driver tuning is thus obtained. The unit contains its own high voltage power supply. Sweep frequency modulation is included.

Receiving system.-Four receivers are included in each WCA system. The sounding receiver is of the tuned radio frequency type, while the other three, including one for each ranging system and an emergency listening receiver, are identical superhetrodyne units.
Sounding receiver-The tuning range is from 22.5 to 25.5 kc; a variable BFO permits adjustment of the audible output above or below 800 cycles.
Ranging/listening receivers -The tuning range is from 13 to 37 kc. A variable BFO permits the audible tone to be adjusted over the range from 0 to 1,600 cycles. Three degrees of i-f selectivity and two of audio are provided by selector switches connected to filters.

Keying and indicating system.-
Ranging-A single range indicator is provided; it is connected with either echo ranging system by operating a selector switch. Keying is mechanical; cams driven by the range indicator disc shaft determine the pulse length and keying interval. Ranges are indicated by the flash of a neon lamp, which revolves at a constant speed, driven by a synchronous motor.
Sounding-The sounding indicator is similar to the range indicator, except that its dial is calibrated in fathoms.

Dimensions and weight.-The components comprising the WCA and WCA-1 systems are located in three compartments on the submarine: Forward torpedo room, control room, and conning tower. In the forward torpedo room are located the QC/NM driver, the QB driver-rectifier, spare receiver, MG set, local control unit, the NM projector, and the hoist-training systems for the QB and QC-JK projectors. The sounding amplifier and indicator are installed inn the control room. In the conning tower are located the range indicator, QB and QC-JK receivers, remote control units, and loud-speaker, arranged in a single stack.

           NAVY TYPE NUMBERS                          Pampanito
Quantity    Unit                     WCA       WCA-1     Serial #
  3    Receiver amplifier         CBM-46165  CBM-46165   #241,F.T.R., #177,#181 C.T.
  2    Receiver power supply      CBM-20062  CBM-20062
  1    Receiver power supply      CBM-20264  CBM-20064   #80,F.T.R.
  1    Range indicator            CBM-55078  CBM-55078   #72,C.T.
  1    Remote train control (QC-  CBM-23279A CBM-23336   #95,F.T.R.,#61,C.T.
         JK).
  1    Remote train control (QB)  CBM-23279  CBM-23336A  #61,C.T.
  1    Driver (QC/NM)             CBM-52251  CBM-52251   #68,F.T.R.
  1    Driver (QB)                CBM-52252  CBM-52252
  1    Sounding amplifier, includ-
         ing)
  1     Receiver                  CBM-46166  CBM-46166
  1     Indicator                 CBM-55077  CBM-55077
  1     Receiver power supply     CBM-20059A CBM-20059A
  2    Filter junction box        CBM-53029C CBM-53029C
  1    Training unit              CBM-10035A CBM-10150
  1    Training unit              CBM-10060  CBM-10149
  2    MG set (training)          CBP-21356  CBP-21472   P.R.
  2    Magnetic controller (train-CAE-21393  CAE-21883   P.R.
  1    MG set (power)             CBP-21706A CBP-21830   F.T.R.
  1    Magnetic controller (power)CAE-21697  CAE-21882
  1    Projector (sounding)       CBM-78155  CBM-78155
  1    Projector (QC-JK)          CBM-78153  CBM-78153
  1    Projector (QB)             CBM-78154  CBM-78154
  1    Loud speaker               CBM-49032  CBM-49032   F.T.R.
  1    Master switch              CAE-24127  CAE-24127
  1    Double jack box            CBM-49057  CBM-49057
  1    Single jack box            CBM-49056  CBM-49056
  1    Jack box                   CBM-49056  CBM-49056
  1    Hand key                   CJB-26003A CJB-26003A.

        DIMENSION AND WEIGHTS OF MAJOR UNITS
      Unit                  Height Width  Depth  Weight
                            Inches Inches Inches Pounds
Receiver amplifier           15      15     15    150
Receiver power supply        10       7      7     26
Sounding indicator amplifier 24      15     22    225
Range indicator              24      15     22    103
Remote train control         24      15     11     88
Driver (QC/NM)               30      15     22    290
Driver (QB)                  22      15     22    275
Training unit                37      15     20    326
MG set (training)            35      17     16    465
Magnetic controller-training 15      13     20     75
MG set (power)               23      13     10    280
Magnetic controller-power    17      13     20    100
Projector (sounding)         23      13     10    280
Projector (QC-JK)            21      19     19    555
Projector (QB)               21      19     19    510

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