Figure 4-51.--Gyrocompass repeaters by letter designation.

An additional feature is the low noise and normal

WATCH STANDING

(nonlow) noise characteristic of several repeaters. In the

The AN/WSN-2 operates unattended after a mode

nonlow noise variety, the servo and dial assembly mount

of operation has been selected and the automatic

directly to the cast housing. In the low noise variety, the

mounting is on vibration isolators similar to rubber

alignment sequence is completed. Audible and visual

shock mounts.

extension alarms will alert watch standers at various

locations upon loss of normal power to the compass or

Figure 4-52 shows a type E repeater minus terminal

if a malfunction exists within the compass.

block and cord. The inner dial is single speed and the

blocked out outer dial is 36 speed. These repeaters are

SHIP'S COURSE INDICATORS

generally located in enclosed spaces, such as the OOD's

(REPEATERS)

repeater on the bridge.

The trend to transistorized equipment has resulted

The basic block diagrams of the various repeaters

in gyro installations being equipped with highly reliable

are shown in figure 4-53. View A shows the type L

transistorized ship's course indicators, or repeaters as

repeater synchro drive. View B displays the type A servo

they are commonly called. Ship's course indicators are

drive single speed. In view C, types B, E, and F are

used to visually display gyrocompass heading data for

depicted, and view D shows the G and H course-to-steer

navigational purposes. They are installed at the helm, on

repeaters.

the bridge wings, in the after steering room, and other

remote locations aboard ship. Figure 4-51 is a

The operation of the components is standard;

breakdown of the various types of ship's course

however, and explanation of the mixer and antistickoff

indicators used with gyrocompass systems.

voltage may be of assistance.

The several variations of mounting dials, data

The 36X synchro control transformer determines

transmission systems, and power requirements for

the accuracy of the indicator, but because this synchro

ship's course indicators will be discussed in the

has 36 null positions for one revolution of the indicator

following paragraphs.

dial, the 1X synchro sets the proper null. The two

Units may be designated as single-speed or 1 and

synchro rotors are connected in shunt through a mixing

36 speed. Single-speed units contain one synchro

network consisting of pairs of diodes and two resistors.

control transformer in larger units and one synchro

The mixing network performs three functions. First, it

receiver in miniature units. The 1 and 36 speed units

effectively opens the 1X synchro signal circuit

provide greater accuracy in reading and contain two

whenever the indicator dial is within 2.5 of null.

control transformers. In the 1 and 36 speed, coarse

Second, it limits or attenuates the 36X synchro signal

control is 1 speed and fine control is 36 speed.

whenever the 36X synchro is more then 2.5 from its

null. Third, it keeps synchro loading to its minimum

Units also may be divided by power requirements

with some using 60 Hz and others using 400 Hz.

allowable level.

Figure 4-51.--Gyrocompass repeaters by letter designation.

4-58