1、F-or-Y3 MIL-D-3L+02A 58 9 7779706 0357477 7 W MIL-D-38402A(USAF) 23 APR 87. I .- f Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: WR-ALC/MIJIEDTA, Robins AFB, GA 31096-5609 by using the self-ad
2、dressed Standardization Document improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. SUPERSEDING 18 MAY 1965 MIL-D-38402(USAF) MILITARY SPECIFICATION GENERAL SPECIFICATION FOR DIRECTION FINDER GROUP AN/ARA-50 This specification is approved for use within the Depar
3、tment of the Air Force and is available for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers the requirements for one type of direction finding equipment, designated Direction Finder Group AN/ARA-50. 2. APPLICABLE DOCUMENTS 2.1 Governmen
4、t documents. 2.1.1 Specifications and standards. The following specifications and standards form a part of this specification to the extent specified herein. Unless otherwise specified, the issues of these documents shall be those listed in the issue of the Department of Defense Index of Specificati
5、ons and Standards (DODISS) and supplement thereto, cited in the solicitation. AMSC N/A FSC: 5826 DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. THIS DOCUMENT CONTAINS 2% PAGES. Licensed by Information Handling ServicesProvided by IHSNot for ResaleNo reproduction or
6、 networking permitted without license from IHS-,-,-MIL-D-38402A( USAF) SPECIFICATIONS I MILITARY I MIL-E-5400 -Electronic Equipment, Airborne, General Specification for MIL-T-5422 -Testing, Environmental, Aircraft Electronic Equipment MIL-M-7793 -Meter, Time Totalizing, 380 to 420 Hz, General MIL-P-
7、9024 -Packaging, materials Handling and Transportability, MIL-F-15160 -Fuses; Instrument, Power and Telephone MIL-R-22659 -Radio Sets AN/ARC-S 1 A( ) and AN/ARC-5 I B( MIL-R-23767 -Receiving Set, Radio AN/ARR-69 MIL-1-25992 -Indicator, Bearing-Distance-Heading ID-526A/ARN MIL-1-27848 -Horizontal Sit
8、uation Indicator AQU/4/A MIL-T-28800 -Test Equipment For Use With Electronic and Fire Control Systems, General Specification For MIL-A-83364 -Antenna AS-2755/ARA Specifications for System and System Segments, General Specification for STANDARDS FEDERAL, FED-STD-5 -Standard Guides for Preparation of
9、Proposed Item Logistics Data Records MILITARY MIL-STD-129 MIL-STD-415 MIL-STD-470 MIL-STD-47 1 MIL- STD-7 O 4 MIL-STD-781 MIL- STD-7 8 5 MIL-STD-810 MIL-STD-826 MIL-STD-83 1 MIL-STD-2073/1A -Marking for Shipment and Storage -Test Points and Test Facilities Design, Standards For -Maintainability Prog
10、ram Requirements (For Systems -Maintainability Demonstration -Electronic Power, Aircraft Characteristics and -Reliability Test Exponential Distribution -Requirements For Reliability Program (Systems and -Environmental Test Methods and Engineering Guidelines -Electromagnetic Interference Test Require
11、ments and -Test Reports, Preparation Of -DoD Materiel Procedures for Development and at a rate of not less than 12 per second when the new bearing occurs in a sector bound by azimuths of IOo and 50. This includes the time required for the indicator to stablize on the new bearing. 25 per second and I
12、Oo per second respectively. Under service conditions the speed of response shall be 3.6 Details of units. 12 a Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NIL-D-38qOZA 58 M 9999906 0357489 3 MIL-D-38402A( USAF) 3.6.1 Antenna AS-909/ARA-48. The an
13、tenna component shall contain the following: a. Receiving element. b. c. RF rotating joint. d. e. Synchro transmitter. f. Appropriate gears. g. Rate generator. ll5V, 400Hz motor for positioning the element. High speed coaxial lobing switch. The antenna component shall be designed in accordance with
14、figure 3. 3.6.1.1 A-c motor. The ac motor shall be capable of rotating the receiving element to the cardioid null at tne rate specified in the speed-of- response requirements. 3.6.1.2 Rotating element. The rotating element shall be kept at the same r-f potential as the housing by spring contacts suc
15、h that the fuselage of the aircraft will provide a suitable ground plane. 3.6.1.3 Synchro transmitter output. 7 The synchro transmitter output shall be capable of driving one pointer load in each of two associated indicators listed under 3.2.1. 3.6.1.4 Rate generator. The rate generator shall provid
16、e damping for tine antenna ser70 positioning system. 3.6.1.5 Field pattern. The antenna field pattern shall approximate a cardioid shape when the antenna is properly terminated. termination of the antenna from one end to the other a mirror image of the field pattern shall be obtained. the antenna r-
17、f output to be square-wave modulated. The resulting square wave signal, after being acted upon by other components, shall be utilized by a phase sensitive motor to position the antenna to the antenna pattern crossover point. The r-f square wave modulation shall decrease to a null at this point. By s
18、witching the This switching of the field pattern caused 3.6.1.6 Antenna gain. The minimum gain of the antenna in the direction of maximum sensitivity shall not be less than 20 db below that of a lossless matched quarter wavelength stub at any frequency within the 225 to 400MHz range. 3.6.1.7 - VSNR.
19、 A maximum VSWR of 3:1 shall be obtainef for the antenna when each of the two ends of tne receiving element are terminated by the coaxial lobng switch. than 5.5:l. The ratio of the two VSWR readings shall not be greater Provided by IHSNot for ResaleNo reproduction or networking permitted without lic
20、ense from IHS-,-,-MIL-D-3902A 54 M 7447Ob 0357440 T m MIL-D-38402A( USAF) 3.6.2 Amplifier-Relay Assembly AM-3624/ARA-50. The amplifier-relay assembly shall conform to figure 4. 3.6.2.1 Amplifier module. This transistorized module shall synchronously filter and amplify the square-wave signal demodula
21、ted by the associated receiver. This signal shall control a saturable transformer and provide a 400Hz output signal phased to rotate the antenna toward the null position. Circuitry shall be included to utilize the antenna rate generator damping voltage for reducing tne servo system hunting and overs
22、hoot. oscillator shall be included to provide power for the antena lobing switch and the rate generator control winding as well as the synchronous filter and phase detecting circuits within the amplifier. A square-wave 3.6.2.1.1 Square-wave oscillator frequency. The square-wave oscillator frequency
23、shall be 75 to 200Hz. 3.6.2.2 Relay module. This module shall contain a DPDT coaxial crossover switch for connecting the associated communications transmitter-receiver to either the communications antenna or DFG antenna. completing the circuit ground with the transmitter receiver control or by the p
24、ush-to-talk switch so that transmission shall always be with the communication antenna. It shall be operated by The relay shall be operated by a 28VDC. 3.6.2.2.1 - VSWR. The VSWR of the relay module shall not be more than l.3:l with a resistive 50-ohm termination. 3.6.3 Mounting MT-lgSS/ARA-50. This
25、 mounting shall contain the necessary shock mounts for the amplifier-relay assembly and shall conform to figure 5. 3.6.4 Antenna AS-2755/ARA. The AS-2755/ARA antenna shall be used in AiWARA-50 DFG installations requiring an antenna that is rotated 90 from normal orientation. accordance with MIL-A-83
26、364. The requirements for the AS-27WARA antenna shall be in 3.7 Weight. The weight of the Direction Finder Group AN/ARA-SO shall be kept to a minimum and shall not exceed the following: a. Antenna AS-gOg/ARA-48: 10 pounds (4.53 Kg) . b. Amplifier-Relay Assembly AMo3624/ARA-50 including mounting MT-
27、1955/ARA-50: 6.5 pounds (2.94 Kg). 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for inspection. Unless otherwise specified in the contract or purchase order, the supplier is responsible for the performance of all inspection requirements as specified herein. Except as otherwise specified, the s
28、upplier may utilize his own facilities or any comercial laboratory acceptable to the Government. The Government reserves the right to perform any of the inspections set forth in the specification where such 14 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from
29、IHS-,-,-MIL-D-38402A 58 W 999Ob OL57q7L L W MIL-D-38402A( USAF) inspections are deemed necessary to assure supplies and services conform to prescribed requirements. 4.2 Document confliction. The quality assurances provisions of MIL-E-5400 and the requirements specified herein shall be applicable to
30、this specification. When the two documents conflict, this specification shall govern. 4.2.1 Classification of tests. The inspection and testing of the direction finder group shall be classified as follows: a. Preproduction testing. b. Acceptance tests. 4.3 Test conditions. Unless otherwise specified
31、, the equipment shall be subjected to the tests under the following test conditions: a. Ambient air: Temperature: Pressure: Prcvailing laboratory conditions 60% to 90% (16OC to 32OC) b. Vibration: None c. Humidity: Rom ambient d. Warm-up time: 5 minutes maximum e. Input power: 115VAC, 400Hz, nominal
32、 27.5VDC nominal 26VAC, 400Hz, nominal f. The transistors or magnetic elements used shall be selected at random from representative types. 4.4 Preproduction testing. 4.4.1 Preproduction test samples. The preproduction test samples shall consist of models representative of the production equipment. t
33、ested under the test conditions specified herein and at the point designated by the contract. 4.4.1.1 Sampling instructions. The contractor shall conduct tests on 8 preproduction sample equipments to determine that the design of the equipments meet the requirements specified herein. conducted in acc
34、ordance with the test procedures specified herein. They shall be The contractorss test shall be 4.4.1.1.1 Testing schedule. Three of the sample equipments shall be processed as in table V, VI and VI1 (See para d.). A minimum of 5 preproduction I. I Provided by IHSNot for ResaleNo reproduction or net
35、working permitted without license from IHS-,-,- MIL-D-38402A 58 = 7777906 0157472 3 m Test Examination of product Functional tests Environmental tests as follows: I MIL-D-38402A( USAF) Applicable Paragraph 4.6.1 4.6.2 4.6.3 * samples shall be tested for reliability in accordance with the requirement
36、s of 4.6.7. accordance with the requirements of 4.6.7. Two of the 5 samples shall be continually tested for longevity in Test Examination of product TABLE V. Sample number I test. Test Applicable Paragraph I Applicable Paragraph 4.6.1 Examination of product Functional tests Environmental tests as fo
37、ll: Shock Salt spray Explosion Sand and dust interference Functional tests Power variation tests Field tests 4.6.1 4.6.2 4.6.3 4.6.5 4.6.2 4.6.4 4.6.6 Temperature-altitude Humidity Vibration Acceleration 4.6.3.2 I 16 Provided by IHSNot for ResaleNo reproduction or networking permitted without licens
38、e from IHS-,-,-4.4.2 Preproduction tests. Preproduction tests shall consist of the tests specified under 4.6, subject to the test conditions specified herein. , Test Examination of product 4.5 Acceptance tests. Acceptance tests shall consist of individual tests and reliability acceptance tests. Appl
39、icable Paragraph 4.6.1 4.5.1 Individual tests. Each Direction Finder Group shall be subjected to the following tests in table VI11 as described under 4.6, Test methods, of this specification: TABLE VIII. Individual tests. I Functional tests I 4.6.2 I 4.5.2 Reliability acceptance test. The first 10 d
40、irection finder equipments of the production run shall be used for reliability demonstration. The reliability testing shall be in accordance with test level F of MIL-STD- 781. decision is reached. The test group shall be continually tested until an accept or reject 4.5.2.1 Rejection and retest. Acce
41、pt-reject criteria for sampling plan equipments shall be in accordance with test plan XXVII of MIL-STD-781. No equipment from the production run of which the test group is a part shall be shipped until an accept decision has been reached on that test group. 4.5.3 Defects in equipments already accept
42、ed. The investigation of a test failure could indicate that defects may exist in equipments already accepted. If so, the contractor shall fully advise the procuring activity of all defects likely to be found and methods of correcting them. 4.6 Test methods. 4.6.1 Examination of product. The DFG shal
43、l be visually inspected to verify that the materials, design and construction, necessary mechanical measurements marking and wormanship comply with the requirements of this specification. 4.6.2 Functional tests. The procedures and application of functional tests to determine proper performance and c
44、ompliance with the requirements of this specification shall be prepared by the contractor and subject to approval by the procuring activity. The functional tests, as applicable shall be conducted prior to, during, and after the environmental tests specified herein. the complete equipment. Unless oth
45、erwise specified, the functional tests shall be coiiducted on 4.6.2.1 R-f operational test. Satisfactory operation shall be observed under r-f signal conditions at 225.0, 31 1 .O and 397.0M-I. 17 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4.6.2.
46、2 Accuracy and sensitivity test. The system ability to return to the same heading from opposite directions with minimum signal strength shall be checked. 4.6.2.3 Speed of-response test. Speed of rotation for the system from starting points 178“ and 50“ removed and for both counter-clockwise and cloc
47、kwise directions shall be checked, 4.6.2.4 Hunting test. The hunting of the indicator needle at 0 and 180 shall be observed. 4.6.2.5 Overshoot. The needle travel beyond the final heading when the antenna is assuming a bearing from a position 180 removed shall be observed. 4.6.2.6 - Lag. The lag of t
48、he indicator needle when the antenna reference signal source is rotated at a speed of 3 per second shall be noted. 4.6.2.7 Coaxia1,relay. The DPDT coaxial switch contained in the relay module for proper crossover switching shall be tested. 4.6.2.8 - VSWR. The VSWR of the antenna with the r-f chopper
49、 in each of the two positions at frequencies of 225, 311, and 397MHZ shall be measured. The VSWR of the relay module r-f inputs for the energized and unergized conditions at frequencies of 225, 311, and 397 MHz shall be measured, 4.6.3. Environmental test. The following environmental tests on DFG shall When the two documents conflict, be conducted in accordance with class 2 requirements of MIL-T 5422 with the exceptions a
