Volume 1
MIL-HDBK-162A
Section 3
15 December 1965
ITEM NAME: RADAR SET
TYPE: AN/BPS-11A
Synchronizing and Transmitting Systems
in the Combat Information Center. This unit together
Repetition Rate: 600 pps adjustable
with the PPI unit compose the central control station of
plus or minus 30 pps
the equipment.
Pulse Width: 0.5 usec
The transmitter generates RF energy which is
Pulse Shape: Rectangular
shaped into a narrow beam by the radar antenna and
Frequency: 8740 to 8890 mc
radiated toward the area being searched. Radar targets
Peak RF Power: 75 to 100 kw
in the area reflect a minute amount of RF energy
Duty Cycle: 0.03%
(echoes) back to the antenna. These echoes are
Average Power: 22.5 to 30w
amplified and detected by the receiver. The target
RF Lines RG-51/U: Waveguide
echoes appear as bright spots on the PPI screen, ;
Volts Standard Wave Ratio: 1.1:1 max
distances from the center of the screen represent target
Radar Antenna
range and the angular position of the target represents
Horizontal Beamwidth: -.6
it's bearing.
Vertical Beamwidth: 16
The "area search" type of operation just described
Antenna Gain: 29.3 db
generally is performed with the submarine surfaced and
Polarization: Horizontal
using the raised radar antenna. Another tactical use of
Sidelobes: 23 db down (one way) at 6
the radar is "target track" operation in which the
ea side all others over 25 db down
submarine is submerged and the "ST" (periscope)
ST (Periscope) Antenna
antenna is used to avoid detection. Range of targets
Horizontal Beamwidth: 30
within 20 miles can be measured precisely and is
Vertical Beamwidth: 10
automatically applied to the ship1s torpedo data
Antenna Gain: 14 db
computer. Target bearing is obtained by optically
Sidelobes
tracking the target with periscope.
Horizontal: 16 db down at 60 ea side
The radar also has capabilities for cw
Vertical: 14 db down at 20 ea side
communication operations with another similarly
Receiving System
equipped station. During this type of operation, the
Antenna Coupling: Duplex converter, TR
radar functions just as in search operation except that
and ATR tube detector
the radar antenna is pointed at the second station and
Bearing Oscillator: Klystron type 2K25
the operator controls the radar transmissions with a
First Detector: Crystal type 1N23B
telegraph key. A headset is used to aurally monitor the
Second Detector: Electron type type 6AL5
transmissions.
The operator sends messages in
IF. Frequency: 60 mc
international Morse Code or other similar system by
Pre-IF. Bandwidth: 3.5 to 4 mc at 3 db down point
operating the key.
IF. Bandwidth: 9 mc at 3 db down point
Other conventional features of the radar set are
Video Bandpass: 3.5 mc at 3 db down point
automatic frequency control of the 60 mc intermediate
Noise Figure: 17 db
frequency, sensitivity time control of receiver sensitivity,
Frequency Control: Manual, STC, FTC, and AGC
and anti-jam to suppress extraneous signals.
Indicating System
RELATION TO SIMILAR EQUIPMENT
Display Size: 5 in.
None.
Presentation: Type A
TECHNICAL DESCRIPTION
Sweep Ranges: 0 to 4, 10, and 20 mi
Over-All Systems
Sweeps: Normal-A sweep with range step
Maximum Range: 160, 000 yds (80 mi)
expanded 1000 yds after range step
Minimum Range:
200 yds
Range Readout: Counters in yds and mi
Bearing Accuracy: plus or minus 0.25
min increment of yds counter 100 yds
Range Accuracy: O to 60, 000 yds, 25 yds
min increment of mi counter 0.1 mi
plus or minus 0.1% of measured range;
Electrical Range Output: Synchros at
60, 000 to 160, 000 yds plus or minus 2%
2000, 72, 000 and 1, 296, 000 yds revolution
of measured range
PPI Indicator: Range Azimuth Indicator
Power Requirements
AN/SPA-4B (Govt furnished)
General Power: 115v, 60 cyc, 1-ph
Antenna Positioning System
Standby: 1852 va
Operate: 2367 va
Vertical Control
Trans-On: 3072 va
Positions: Raised and stow
Synchro Excitation: 115v, 60 cyc, 1-ph,
Drive: GFE hydraulic system
600 va and 115 va
AN/BPS-11A: 2
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