DEPTH CHARGE DIRECTION INDICATOR (DCDI)
Description.- The depth charge direction indicator (DCDI) is a sonar device used to indicate to a submarine conning officer the general direction of depth charge explosions occurring in his vicinity. By noting which three out of a bank of six indicating lamps are illuminated by the explosion, the officer can tell if it was port or starboard, above or below, and ahead or astern. The equipment contains seven hydrophones, arranged one port, one starboard, one ahead, one astern, one above, and two below in parallel. The circuits are arranged to indicate which of each pair of phones receives the sound impulse first.
Circuits.-Each pair of hydrophones is associated with a pair of amplifier circuits feeding indicator lamps. A pulse received by one hydrophone of a pair will cause its associated lamp to light, at the same time locking out the other circuit of the pair so that it will not operate when it receives the pulse. After three seconds, the lamp is extinguished and the circuits return to normal.
Power supply.-110 volts, d. c.
Hydrophones.-Magnetostrictive, polarized by permanent magnetization.
Tube complement.-3 type 6SN7-GT, 6 type 2051, 6 type 66-6272.
Dimensions and weight Unit Height Width Depth Weight Inches Inches Inches Pounds Amplifier-Indicator 9 13 11 29 Blastphones (7) 16 (#1) 2 12 Blastphone mounts (7) 6 13 5 17 Junction box 7 12 5 29 Line filter 5 10 6 12 (#1) Diameter.Literature.-Preliminary Instruction Book for Sickles Model NL-116 Underwater Sound Equipment.
REFERENCES:The information enclosed here is excerpted from:
Catalogue of Naval Electronic Equipment-April 1946- NavShips 900,116.