Volume 1
MIL-HDBK-162A
Section 3
15 December 1965
AN/SPN-18, -18X
Operating Voltages and Power Requirements:
FUNCTIONAL DESCRIPTION
AN/SPN-18 - 115 vdc
AN/SPN-18X - 115v, 60 cps, 1-ph
Radar Set AN/SPN-18 and -18X are shipboard
Receiver Type: Superheterodyne
equipments that supply position data of ships and
IF. Frequency: 30 mc
landmarks. These equipments provide anticollision
Bandwidth: 8 mc for 1-, 2-, and 4-mi ranges;
data; piloting information through observation of
2.5 mc for 8-, 20-, and 40-mi ranges
shorelines, buoys, and channel markers; and storm
Azimuth Coverage: 360 deg continuous rotation
warning data by tracking heavy rain or snow squalls.
Range Accuracy: 2% on all ranges
The AN/SPN-18 is operated from a dc power source,
Azimuth Accuracy: 1 deg
while the AN/SPN-18X is operated from an ac source.
Range Resolution:
5 yd on 1-, 2-, and 4-mi ranges
Azimuth Resolution: 1.5 deg
RELATION TO SIMILAR EQUIPMENT
Antenna Type: Parabolic reflector with feed
horn
None.
Horizontal Beam Width: 1.9 deg
Vertical Beam Width: 20 deg
Sidelobe Attenuation: 30 db
TECHNICAL DESCRIPTION
Rotation Speed: 9 rpm
Antenna Feed: Waveguide
Frequency: 9320 to 9430 mc
Peak Power Output: 40 kw
Average Power: 20w
INSTALLATION CONSIDERATIONS
Pulse Repetition Rate: 2, 000 pps for 1-, 2-, and
4-mi ranges; 800 pps for 8-, 20-, and 40-mi
Siting: The antenna should be positioned so that
ranges
the radar beam will clear large shipboard
Pulse Width:
structures.
25 sec for 1-, 2-, and 4-mi ranges;
Mounting:
65 sec for 8-, 20-, and 40-mi ranges
Cabling Requirements: The waveguide run from
Type of Presentation: One 16-in. PPI
the base of the antenna to the receiver-trans-
Ranges:
mitter must be made as short and straight as
Searching - 1, 2, 4, 8, 20, and 40 mi
possible.
Tracking - 1, 2, 4, 8, and 20 mi, and up to
Related Equipment:
20 mi on 40-mi range
PRINCIPAL COMPONENTS AND PHYSICAL DATA
COMPONENT
QTY
HEIGHT
WIDTH
DEPTH
UNIT WT.
(Inches)
(Inches)
(Inches)
(Pounds)
Antenna AS-659/SPN-18
1
50
33-3/4
22-1/2
160
Control Indicator C-1261/SPN-18
1
47-3/8
23-1/4
20-1/2
235
Circuit Breaker SA-369/SPN-18X
1
9-3/16
6-1/16
5-1/8
8
(18X only)
Duplexer CU-311/SPN-11
1
Frequency Mixer Stage
1
CV-239/SPN-11
Motor Generator PU-243A/SPN-11
1
20-1/2
13-3/4
9-1/4
170
(18 only)
Motor Generator PU-288/SPN-18X
1
29-1/2
14-3/4
12-9/16
250
(18X only)
AN/SPN-18: 2
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