Volume 1
MIL-HDBK-162A
Section 3
15 December 1965
ITEM NAME: INDICATOR GROUP
TYPE: AN/SPA-25
Equipments VC, VD, VE, VF series, VH, V3 and VJ-1.
a range strobe. Range marks appear on the cathode-
ray tube as concentric rings spaced at intervals that
represent distance from the radar antenna. The range
TECHNICAL DESCRIPTION
strobe appears as an expanding concentric ring whose
Type of Presentation: 1g-in. PPI
expansion is mechanically controlled by the operator.
Range, Max: 300 mi
When the range strobe ring passes through a target, the
Range, Min: 4 mi
target range is shown on a range-window on the front
Sweep Rate: 40 rpm max
panel. The range of a target at a distance of 28 miles or
Sweep Linearity: 1%
less is expressed in yards in the range yards window.
Range Marker Intervals: 1, 2, 5, 10, 25
The range of a target beyond 28 miles is expressed in
and 50 mi
miles in a rangemiles window.
Range Marker Pulse Width: 0.25 usec
Bearing is measured by an electronic bearing
Range Marker Accuracy: 1%
cursor. The cursor appears as a sweep whose azimuth
Range Strobe Pulse Width: 0.25 usec
is mechanically controlled by the operator. When the
Range Strobe Accuracy: 0.15 to 5 mi, 0.05
bearing cursor is activated, normal video is blanked
mi; 5 to 36 mi, 1%; 26 to 300 mi, 2%.
from the presentation. The cursor crank control is then
Input Trigger Pulse Width: 1 to 10 usec
hand-operated to make the cursor pass through the
Input Trigger Amplitude: 5 to 50v
target on the indication CRT.
The bearing thus
Pulse Repetition Rate: 6 to 3000 pps
determined is shown on the cursor bearing window. The
Video Input: 1 to 2.5v pos
electronic
cursor
provides
accurate
bearing
Operating Voltages and Power Requirements:
measurements since parallax, a fault common to
115v, 60 cps, 1-ph, 180w
mechanical cursors, is eliminated.
INSTALLATION CONSIDERATIONS
RELATION TO SIMILAR EQUIPMENT
Not available.
This equipment replaces Radar Indicating
PRINCIPAL COMPONENTS AND PHYSICAL DATA
COMPONENT
QTY
HEIGHT
WIDTH
DEPTH
UNIT WT.
(Inches)
(Inches)
(Inches)
(Pounds)
Indicator AN/SPA-25
1
17-1/16
18-23/32
23-53/64
180
*DRA Unit
1
Accessory Case
1
19-1/4
31
15-1/8
NOTE: *Mounts on side of Indicator.
REFERENCE DATA AND LITERATURE
Technical Manuals:
NAVSHIPS 92981
AN/SPA-25: 2
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