ASV--Air-To-Surface Search Sets

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SCR-521-A or ASVC and SCR-521-B or ASE Long Wave ASV Sets

SCR-521 in B-17 indicating transmitting (search) antenna, indicator unit, receiving (search ) antenna, inverter, receiving (homing) antenna, control panel, radio receiver, transmitter, receiving (homing) antenna, and transmitting (homing) antenna.
SCR-521 in B-17

DESCRIPTION: Airborne long-wave search set for patrol bombers. Range and left-right indication are provided on an ASV scope. IFF identification signals are displayed directly on the scope. These sets are no longer in production.
USES: For locating and homing on craft or coastal targets, and for navigating. Sets work with SCR-621 or YH racon.
PERFORMANCE: Reliable maximum ranges: surfaced submarines (broadside), 6 miles; 4,000-8,000 ton ship, 25 miles; well-defined coastline, 60 miles. Minimum range is 350 yds. Range accuracy, ± 10%. Sets cover forward 150° when searching, 40° when homing on a target. Bearing accuracy in homing is ± 2° to ± 5°.
TRANSPORTABILITY: Sets are packed in 7 units for shipment, weighing a total of 300 lbs. Largest package is 16" x 21" x 24" and weighs 78 lbs.
INSTALLATION: SCR-521's are installed in B-17, B-24, B-25 and B-34 planes. ASVC and ASE are installed in B-17, B-24, PBY5, PBY5A, and PBN. The external antennas reduce plane's top speed by about 5 to 7 knots, and the forward nose antenna interferes with the firing of the forward flexible guns. (The addition of a polyplexer in future installations will eliminate the nose antenna).
PERSONNEL: Army requires one operator and one maintenance man per set. Navy requires one operator per set and 4 maintenance men per squadron.
POWER: Total primary power required: (a) from combined AC-DC generator -- 2.6 amps., 27.5 v. DC and 500 watts, 115 v., 800-2400 cycles AC; or (b) from primary DC generator, requiring use of motor-alternator -- 39 amps., 27.5 v. DC.

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ASA Medium Wave ASV Set

ASA in PB2Y indicating control box, receiver, transmitter, antenna, indicator, and alternator.
ASA in PB2Y

DESCRIPTION: Medium-wave airborne search set designed for installation in large patrol bombers. Provides range and right-left indication on ASV scope. Includes provisions for altimeter to 20,000 feet. (This set is no longer in production).
USES: For locating and homing on surface craft or coastal cities beyond visual range, and for navigating. A modification kit is available for IFF identification provision.
PERFORMANCE: Reliable maximum ranges: surfaced submarine (broadside), 10 miles; 4,000-8,000 ton ship, 35 miles; well-defined coastline, 60 miles. Minimum range is 350 yards. Range accuracy is ± 5%. Covers 180° in bearing when searching and 40° when homing. Bearing accuracy in homing is from ± 2° to ± 5°.
TRANSPORTABILITY: Packed in 5 units for shipment, including spares for 200 hours operation, and weighing a total of 569 lbs. Largest package measures 35" x 27" x 291/2" and weighs 223 lbs.
INSTALLATION: Installed chiefly in PB2Y-3's, adding about 353 lbs. to plane's weight and reducing its top speed by 4 to 5 knots.
PERSONNEL: One operator per set and 4 maintenance men per squadron are required. In normal operations, the operator is relieved by other members of the crew.
POWER: Total primary power required is 78 amps., 27.5 V from plane's DC supply.

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ASB & "ASB Series" Medium Wave ASV Sets

ASB in TBF
ASB in TBF

DESCRIPTION: Airborne medium-wave search sets for carrier-based planes and flying boats. Provides range and right-left indication on an ASV scope. There are eight models of ASB. Corresponding components of each model are interchangeable. "ASB Series" is an improved transmitter and receiver, used as replacement in any ASB set.
USES: For locating and homing on surface craft and coastal cities, for assistance in night bombing and torpedo attacks, and for navigating. All sets have provisions for IFF and YJ racon response.
PERFORMANCE: Reliable maximum ranges: surface submarine (broadside), 8 miles; 4,000-8,000 ton ship, 25 miles; well-defined coastline, 60 miles. "ASB Series" extends these ranges to 15 miles on surfaced submarine, 25-35 miles on 5,000-ton ship, and 70 miles on coastline. Minimum range is 350 yards. Range accuracy, ± 10%. Covers 180° in bearing when searching, and 40° when homing on target. Bearing can be estimated to about ± 3°, when homing.
TRANSPORTABILITY: ASB-4 and ASB-8 are packed in 2 units for shipment, weighing a total of 171 lbs. Other models are packed in one unit, weighing 240 lbs. and measuring 37" x 42" x 311/2". Package includes operating spares for 200 hours. Crated "ASB Series" will be a smaller package.
INSTALLATION: Installed in SBD, SO3C, TBF, SB2 C, PBY-5, PBY-5A, PBN, PB4Y, PV-3. Average weight is 152 lbs. Set cuts plane's top speed by 2 to 5 knots.
PERSONNEL: One operator per set is required, and 12 maintenance men per carrier-based group or 4 per land-based squadron. One operator serves a ten-hour watch, relieved by other members of crew.
POWER: Total primary power required: (a) from combination AC-DC primary generator (NEA-3 or NEA-5) -- 350 watts for ASB 400 watts for "ASB Series", 115 V, 600-1400 cycles AC (plus 85 watts for repeat indicator); or (b) from primary DC generator, requiring use of motor-alternator 9800-1-B) -- 25 amps. for ASB, 30 amps. for "ASB Series", 27.5 V DC.

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SCR-517-A, SCR-517-B or ASC-1, and SCR-517-C Microwave ASV Sets

ASC-1 in PB2Y-3 indicating spinner, junction box, amplidyne amplifier, amplidyne, motor alternator, voltage regulator, control box indicator, receiver, power supply and transmitter and receiver.
ASC-1 in PB2Y-3

DESCRIPTION: Airborne microwave search sets for installation in patrol bombers. Range and azimuth are provided on PPI scope in SCR-517-B or ASC-1, and on B scopes in other models. Sets have provisions for IFF.
USES: For locating and homing on friendly or enemy surface craft or coastal targets and for navigation. All sets except SCR-517-A work with AN/CPN-3 racon.
PERFORMANCE: Maximum reliable ranges: surface submarines (broadside), 18 miles; 4,000-8,000 ton ship, 40 miles; well-defined coastline, 90 miles. Range accuracy, ± 3%. SCR-517-A and SCR-517-C cover 180° forward; SCR-517-B or ASC-1 covers 360°. Azimuth accuracy is ± 3°.
TRANSPORTABILITY: ASC-1 is packaged in 4 units for shipment, weighing a total of 689 lbs. Largest package is 43" x 37" x 25" and weighs 177 lbs. Army sets are packaged in 6 units, weighing a total of 850 lbs. Largest package is 29" x 40" x 28" and weighs 180 lbs. Test set IE-30 (For SCR-517-A and SCR-517-C) or IE-57 or LZ (for SCR-517-B) and PE-143 power equipment are required for maintenance.
INSTALLATION: SCR-517-A and SCR-517-C are installed in B-17, B-18, B-24, B-25, and B-34 planes. Average installed weight is 600 lbs. In B-17 and B-25, the antenna is housed in retractable ventral turret replacing the gun turret. In the B-34, a new opening for antenna housing is cut in the fuselage under the upper gun turret, which can no longer be used. SCR-517-B is installed in B-24. ASC-1 is installed in PB2Y-3, adding about 550 lbs. to plane's weight and reducing its top speed by 2 to 5 knots.
PERSONNEL: One operator and one maintenance man per set are required by Army; Navy requires 4 maintenance men per squadron.
POWER: Total primary power required is 105 amps., 27.5 v., from plane's DC supply.

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SCR-717-A & SCR-717-B Microwave Small-Package ASV Sets

SCR-717-A in B-24 indicating synchronizer, rectifier, indicator, modulator and transmitter, and antenna.
SCR-717-A in B-24

DESCRIPTION
AND USES:
This is a microwave small package ASV developed from the SCR-517. The SCR-717-A provides B scopes for pilot and operator with maximum ranges of 5, 20, 50, and 100 nautical miles. Either the forward or rear 180° is scanned as desired. The SCR-717-B provides PPI scopes for pilot and operator with maximum ranges of 4, 25, 40, and 100 nautical miles. 360° scanning is provided on all ranges, with open center indication on the 4 mile range. The sets have provisions for IFF identification connections. Includes connections for operation with IR, racon and AN/APQ-5 (radar bomb-sight) equipment. Test set IE-57 or LZ and PE-143 power equipment are required for maintenance.
PERFORMANCE: Estimated maximum range: 70 miles on 5,000-10,000 ton ships, 20 miles on surfaced submarine. Minimum range 600 ft.
TRANSPORTABILITY: Each set is packaged in 5 units the largest of which measures 24" x 37" x 43" and weighs 177 lbs. Total shipment weighs 773 lbs. and occupies 78 cu. ft.
INSTALLATION: Antenna is installed in a retractable belly turret in the B-24 or B-25 replacing the lower gun turret. Remaining components are installed in radio compartment. Total installed weight including operator's seat and retraction gear is 560 lbs.
PERSONNEL: One radar operator and one maintenance man per set are minimum requirement.
POWER: Primary power required: 100 amperes at 27.5 volts from plane's DC supply.

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ASD Microwave ASC Set

ASD Installed in PV-1 indication ASD amplifier, antenna, junction box, ASD transmitter, ASD receiver and operator control box.
ASD Installed in PV-1

DESCRIPTION: Airborne microwave search set for installation on patrol planes. Provides range and bearing on B scopes, furnished to operator and pilot.
USES: For locating and homing on friendly or enemy surface craft or on coastlines; for general navigation; and for bombing of coastal or marine targets. Set has provisions for operating on racon (AN/CPN-6) and IFF connections for identification of targets. ASD can be used with AN/APQ-5 for blind bombing.
PERFORMANCE: Reliable maximum ranges: surfaced submarines (broadside), 16 miles; 4,000-8,000 ton ship, 27 miles; well-defined coastline, 45 miles. Minimum range is 200 yards. Range accuracy, ± 10%. Covers 140° of bearing with accuracy of ± .3°. Elevation limits are from +91/2° to -91/2°.
TRANSPORTABILITY: Packed in 6 units for shipment, including spares for 200 hours operation, and weighing a total of 499 lbs. Largest unit measures 38" x 29" x 16" and weighs 190 lbs.
INSTALLATION: Installed weight in PV-1 is 295 lbs. Effect on plane's speed is negligible.
PERSONNEL: One operator per set and 4 maintenance men per squadron are required. In normal operations, pilot uses his scope to relieve operator.
POWER: Total primary power required: (a) from combination AC-DC primary generator (NEA-3 or NEA-5) -- 7.7 amps., 27.5 V DC and 875 watts, 115 V, 400-2400 cycles AC; or (b) from DC primary generator, requiring use of motor alternator (800-1-B) -- 58 amps., 27.5 V DC.

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ASG, ASG-1, AN/APS-2a (ASG-2) & AN/APS-2 (ASG-3) Microwave ASV Sets

ASG in Blimp indicating main generator, spinner nagelle, PPI nad control indicator and remote PPI.
ASG in Blimp

DESCRIPTION: Airborne microwave search sets. ASG and AN/APS-2A for blimps, ASG-1 and AN/APS-2 for patrol bombers. PPI scopes give range and bearing.
USES: For locating and homing on surface craft and for general navigation. AN/APS-2 can be used with AN/APO-5 for blind bombing. All sets have provisions for IFF and for racon AN/CPN-3.
PERFORMANCE: Maximum reliable range: surface submarine (broadside), 18 miles; 4,000-8,000 ton ships, 40 miles; well-defined coastline, 90 miles. Minimum range is 400 yards. Range accuracy is ± 7%. Sets cover 360° with bearing accuracy of ± 3°.
TRANSPORTABILITY: ASG is packaged in 5 units for shipment, weighing a total of 741 lbs; ASG-1 in 7 units weighing 764 lbs. Largest package for ASG measures 591/2" x 47" x 29" and weighs 372 lbs.; for ASG-1, 35" x 261/2" x 46" weighing 257 lbs. AN/APS-2A is packaged in 5 units, weighing a total of 764 lbs; AN/APS-2 in 7 units weighing 741 lbs. Largest unit for AN/APS-2A measures 591/2" x 47" x 29" and weighs 372 lbs.; for AN/APS-2, 35" x 261/2" x 46" weighing 257 lbs.
INSTALLATION: ASG and AN/APS-2A are installed in K ships; ASG-1 and AN/APS-2 in PBM-1, PBM-3c, PBJ, and PB4Y patrol bombers. In the PBJ and PB4Y-1, the lower ventral gun turret is removed. Average installed weights are 350 lbs. for ASG and AN/APS-2A, and 360 lbs. for ASG-1 and AN/APS-2. Installations reduce the aircraft's top speed by 2 to 5 knots.
PERSONNEL: One operator per set is required, relieved by other members of the crew. 4 maintenance men are required per squadron.
POWER: Total primary power required: (a) from combination AC-DC primary generator -- 5.2 amps., 27.5 V DC and 850 watts, 115 V, 400-2400 cycles AC; or (b) from DC primary generator, requiring use of motor alternator -- 55.2 amps., 27.5 V DC.

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*AN/APS-3 (ASD-1) Microwave ASV and Torpedo-Laying Set

AN/APS-3 in PV-2 indicating antenna, RF head, pilot's scope, indicator, power, modulator, scope, operator, lubbers line potentiometer and control box.
AN/APS-3 in PV-2

DESCRIPTION: Airborne microwave search and torpedo-laying set, for installation on patrol planes or torpedo bombers. Range and bearing are provided on B scopes supplied to operator and pilot.
USES: For locating and homing on friendly or enemy surface craft and coastal targets, for general navigation, and for blind bombing (with AN/APQ-5) and torpedo-laying. Includes provisions for operating on AN/CPN-6 racon and for IFF identification connections.
PERFORMANCE: Maximum reliable ranges: surfaced submarine (broadside), 20 miles; 4,000-8,000 ton ship, 40 miles; well-defined coastline, 80 miles. Minimum range is 200 yards. Range accuracy, ± 1%. Covers 160° in bearing, with accuracy of ± 3°. When 60° of bearing is expanded on scopes for torpedo-laying, accuracy is ± 1°. elevation limits are +9° to -9°.
TRANSPORTABILITY: Packed in 6 units for shipment, including spares for 200 hours operation, and weighing a total of 499 lbs. Largest unit measures 38" x 29" x 16" and weighs 190 lbs.
INSTALLATION: Installed in PV-2, TBM, TBU, PBN and PBY-5, adding about 300 lbs. to plane's weight. Effect on plane's speed is negligible.
PERSONNEL: One operator per set and 4 maintenance men per squadron (or 12 per group on carrier) are required. In normal operations the pilot uses his scope to relieve operator.
POWER: Total primary power required: (a) from combination AC-DC primary generator -- 7.7 amps., 27.5 V DC and 875 watts, 115 V, 400-2400 cycles AC; or (b) from primary DC generator, requiring use of motor-alternator -- 58 amps., 27.5 V DC.

* Available for issue in latter part of 1943.

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AN/APS-4 (ASH) Lightweight ASV and Interception Set

AN/APS-4 in SC-1
AN/APS-4 in SC-1

DESCRIPTION: Lightweight airborne search and interception set primarily for carrier based aircraft. All major components are contained in a single pressurized housing similar to a Mk 41 depth bomb, and detachable in the same manner as an ordinary bomb.
USES: For locating and homing on ships and coastal targets; for locating planes and making interception approaches; and for navigating. Range, bearing and elevation data are given as B or modified H indications appearing on the same scope. Set operates with AN/CPN-6 racon, and has provisions for IFF connections for identifying targets.
PERFORMANCE: Reliable maximum ranges are 15 miles on surfaced submarines (broadside), 30 miles on 4,000-8,000 ton ship, 75 miles on well-defined coastline, and 5 miles on aircraft. Aircraft can be tracked to 300 feet. Range accuracy is ± 5%. Covers ± 75° in bearing. Bearing accuracy is ± 3°. Covers -30° to +10° in elevation when searching, ± 30° when intercepting. Elevation accuracy is ± 3°.
TRANSPORTABILITY: Packaging not yet fixed, but set will be shipped in two cases, largest of which will measures 24" x 24" x 60" and weigh approximately 150 lbs. Total packaged weight should not exceed 250 lbs.
INSTALLATION: For installation in light carrier-borne aircraft. Installed weight is 150 lbs.
PERSONNEL: One operator per set is required, except when operated by the pilot of single-place aircraft. 12 maintenance men per group for carrier-based planes, or 4 per squadron for shore-based planes are recommended.
POWER: Total primary power required: (a) from combination AC-DC primary generator -- 10 amps. 27.5 V DC and 1000 watts, 115 V, 800-2400 cycles AC; or (b) from primary DC generator, requiring use of motor-alternator -- 68 amps. 27.5 V DC.

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