1、AMSC N/A FSC 5985 INCH-POUND MIL-DTL-25879G 8 February 2012 SUPERSEDING MIL-DTL-25879F 12 June 2007 DETAIL SPECIFICATION SWITCH, RADIO FREQUENCY TRANSMISSION LINE, COAXIAL TYPE SA - 521A/A This specification is approved for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1
2、.1 Scope. This specification covers the requirements for one type of radio frequency (RF) switch, intended specifically for use in switching coaxial lines between multiple communication and navigation antennas. 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this section are specified i
3、n sections 3 and 4 of this specification. This section does not include documents cited in other sections of this specification or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned that they m
4、ust meet all specified requirements of documents cited in sections 3 and 4 of this specification, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and handbooks form a part of this document to the exten
5、t specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract (see 6.2). DEPARTMENT OF DEFENSE SPECIFICATIONS MIL-PRF-39012/1 - Connectors, Plug, Electrical, Coaxial, Radio Frequency (Series N (Cabled), Pin Contact, Class 2). MIL-PRF-39
6、012/2 - Connectors, Plugs and Receptacles, Electrical, Coaxial, Radio Frequency, (Series TNC (Cabled), Flange Mounted, Socket Contact, Class 2). MIL-DTL-32054 - Mounting MT-1995/A for Coaxial Type SA-521A/A Radio Frequency Transmission Line Switch. DEPARTMENT OF DEFENSE STANDARDS MIL-STD-202 - Elect
7、ronic and Electrical Component Parts. MIL-STD-461 - Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment. (Copies of these documents are available on line at https:/assist.daps.mil/quicksearch or https:/assist.daps.dla.mil or from the Standardizati
8、on Document Order Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094.) Comments, suggestions or questions on this document should be addressed to DLA Land and Maritime, ATTN: VAT, Post Office Box 3990, Columbus, OH 43218-3990, or emailed to TubesAmpsdla.mil. Since contact information
9、 can change, you may want to verify the currency of this address information using the ASSIST Online database at https:/assist.daps.dla.mil. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-25879G 2 2.3 Non-Government publications. The followi
10、ng documents form a part of this document to the extent specified herein. Unless otherwise specified, the issues of the documents are those cited in the solicitation or contract (see 6.2). NATIONAL CONFERENCE OF STANDARDS LABORATORIES (NCSL) NCSL-Z540.3 - Calibration Laboratories and Measuring and T
11、est Equipment. (Copies can be obtained online at http:/www.ncsli.org or from National Conference of Standards Laboratories (NCSL), 2995 Wilderness Place, Suite 107, Boulder, CO 80301-5404) 2.4 Order of precedence. Unless otherwise noted herein or in the contract, in the event of a conflict between t
12、he text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. REQUIREMENTS 3.1 First article approval. Coaxial switches furnished un
13、der this specification shall be a product which meets requirements for first article approval (see 4.4 and 6.3). The switch, SA-521A/A, and mounting, MT-1995/A (see MIL-DTL-32054), shall be first article approved together and at the same time (see figure 1). 3.1.1 Classification. The SA-521A/A switc
14、h shall be designed for 70,000 ft. altitude and continuous sea level operation over the temperature range of -54 to +71C (+95 intermittent operation), with exceptions as specified herein. 3.1.2 Materials. Materials shall be used that will enable the switches to meet the requirements of this specific
15、ation. Acceptance or approval of any constituent material shall not be construed as a guaranty of the acceptance of the finished product (see 4.2). 3.1.2.1 Dissimilar metals. Unless suitably protected against electrolytic corrosion, dissimilar metals shall not be used in intimate contact with each o
16、ther. Dissimilar metals are defined as metal specimens that are in contact or otherwise electrically connected to each other in a conductive solution and that generate an electric current. 3.1.2.2 Fungus. Materials used in the construction of switches shall be fungus inert. Fungus inert material is
17、defined as a material which, in all modified states and grades, is not a nutrient to fungi. 3.1.2.3 Finish. If the body of a switch is painted, it shall be painted with a semi-gloss or dull enamel finish. Unless otherwise specified, all aluminum not intended to make electrical contact shall be treat
18、ed. For guidance on finishes see 6.6. 3.1.2.4 Pure tin. The use of pure tin, as an underplate or final finish, is prohibited both internally and externally. Tin content of switch components and solder shall not exceed 97 percent, by mass. Tin shall be alloyed with a minimum of 3 percent lead, by mas
19、s (see 6.8). 3.1.3 Maintainability. Provisions shall be made for rapid checkouts of the equipment using standard test equipment only. Mounting provisions shall ensure that a minimal amount of maintenance time and effort is required for removal and replacement, using standard tools only. Provided by
20、IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-25879G 3 FIGURE 1. Outline and dimensions of switch type SA-521A/A. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-25879G 4 SCHEMATIC SHOWN IN DEEN
21、ERGIZED CONDITION Inches mm Inches mm .125 3.18 1.875 47.62 .33 8.38 1.91 48.51 .56 14.22 1.95 49.53 .72 18.29 2.125 53.98 .885 22.48 2.75 69.85 1.125 28.58 3.19 81.03 NOTES: 1. Dimensions are in inches. 2. Metric equivalents (to the nearest 0.01 mm) are given for general information only. 3. Unless
22、 otherwise specified, tolerances are .010 inch (0.25 mm) for three place decimals and .03 inch (0.76 mm) for two place decimals. 4. Keyway of power connector to be at 12 oclock position. 5. The centerline of the power connector shall be no higher than the centerline of the switch body. 6. Positive e
23、lectrical continuity between the switch unit and the individual fasteners shall be assured. FIGURE 1. Outline and dimensions of switch type SA-521A/A - Continued. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-25879G 5 3.2 Design and constru
24、ction. The RF transmission switch SA-521A/A shall be designed to operate as a single-pole double-throw coaxial switch. When the switch is de-energized, the internal RF connection shall return to a normally closed condition with the common terminal connected to terminal number 2. Separate functions s
25、hall be provided to permit both outputs to be connected to the common terminal at once and for both outputs to be disconnected at once when specially energized. The switch shall employ make-before-break contact arrangements for switching from position 1 to position 2, and from position 2 to position
26、 1. 3.2.1 Drawings and procedures. The original design and construction drawings and production procedures as approved by first article testing shall remain available for the inspection by the cognizant government inspector. No changes or waivers shall be allowed without approval of the acquiring ac
27、tivity (see 6.3). 3.2.2 General. Any military specification, standard, or handbook referred to in this specification may be replaced by an equivalent commercial standard as determined by the acquiring activity (see 6.3). 3.2.3 Frequency. The RF switch shall be designed to operate at any frequency up
28、 to and including 1.250 GHz. 3.2.4 Nominal impedance. Nominal impedance of the switch shall be 50 . 3.2.5 Mounting provisions. The RF switch shall mate with mounting MT-1995/A (see MIL-DTL-32054). Positive electrical continuity between the switch unit and the individual fasteners shall be assured. 3
29、.2.6 Connectors. 3.2.6.1 Power connector. The power connector shall be sealed, and shall mate with connector MS3456L10SL3S. The pin arrangement shall be as follows: a. When pins A and C are connected to a 28 V dc source, the switch shall present a parallel connection of both outputs to the input. b.
30、 When pins B and C are connected to a 28 V dc source, the switch shall present an open circuit between both outputs and the input. c. When pins A and B are parallel and connected with pin C to a 28 V dc source, the switch shall change over from antenna number 2 position to antenna number 1 position.
31、 d. When the switch is de-energized, the input shall be connected to antenna 2. e. Pin C shall be considered to be the common terminal and shall not be grounded internally. 3.2.6.2 RF connectors. The RF switch shall be equipped with a receptacle connector meeting the mating dimensions of MIL-PRF-390
32、12/2 to mate with “N“ series connector (M39012/01-0002 or M39012/01-0005) in accordance with MIL-PRF-39012/1. The input shall be labeled “IN“; the outputs shall be labeled as shown on figure 1. 3.2.6.3 Connector caps. All connectors shall be supplied with push-on caps to prevent connector damage and
33、 the entrance of moisture and foreign material during storage. 3.2.7 RF contact construction. The RF contacts of the switch shall be constructed to provide a wiping action during operation. 3.2.8 Housing. The housing shall be immersion-proof (see 3.4.2 and 4.7.15). 3.2.9 Retention devices. All screw
34、s and other hardware shall be adequately equipped with retaining devices to prevent loosening from vibration or shock over the life of the switch. 3.2.10 RF interference. RF interference control requirements shall be in accordance with MIL-STD-461. 3.2.11 Weight. The weight of the switch shall not e
35、xceed 1 pound. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-25879G 6 3.3 Performance (electrical). 3.3.1 Operating voltage. When tested as specified in 4.7.2, the switch shall operate properly within the limits and conditions specified. 3.
36、3.2 Operating current. When tested as specified in 4.7.3, the operating current shall not exceed one ampere. 3.3.3 Switching rate. When tested as specified in 4.7.4, the switch shall operate properly up to 140 operations per minute. 3.3.4 Switching time. When tested as specified in 4.7.5, the switch
37、ing time shall not exceed 20 ms. 3.3.5 Voltage standing wave ratio (VSWR). When tested as specified in 4.7.6, the VSWR shall not exceed 1.2:1. 3.3.6 Insertion loss. When tested as specified in 4.7.7, the insertion loss shall not exceed 0.20 dB. 3.3.7 Isolation. When tested as specified in 4.7.8, the
38、 isolation shall be not less than 40 dB. 3.3.8 Insulation resistance (RF). When tested as specified in 4.7.9, the insulation resistance shall be not less than 10 Meg. 3.3.9 Dielectric withstanding voltage. When tested as specified in 4.7.10, all current carrying portions of the switch shall successf
39、ully withstand the application of 1,000 V rms at 60 Hz. 3.3.10 RF power handling capability. When tested as specified in 4.7.11, the switch shall be capable of switching 4.5 kW peak power at 0.1 percent duty cycle (4.5 W average) and carry 100 W average power in a steady-state condition. 3.3.11 Inte
40、rnal RF contact resistance. When tested as specified in 4.7.12, the switch contact resistance shall not exceed 0.025 at 1 A. 3.3.12 Connector torque. When tested as specified in 4.7.13, the power and RF connectors shall withstand 45 foot-pounds of torque. 3.4 Performance (environmental). 3.4.1 Therm
41、al shock. When tested as specified in 4.7.14, the switch shall meet the original parameters for switching time, VSWR, and dielectric withstanding voltage. 3.4.2 Immersion. When tested as specified in 4.7.15, the switch shall show no evidence of leaking. 3.4.3 Shock. When tested as specified in 4.7.1
42、6, the switch shall meet the original parameters for switching time and VSWR. 3.4.4 Random vibration. When tested as specified in 4.7.17, continuity of the RF contacts shall remain stable in each of all possible positions. After completion of the vibration test, the switching time and VSWR shall mee
43、t the original parameters. 3.4.5 Humidity. When tested as specified in 4.7.18, the switch shall show no visible evidence of deterioration and the dielectric withstanding voltage test shall meet the original parameters. 3.4.6 Salt atmosphere. When tested as specified in 4.7.19, the switch shall show
44、no evidence of external deterioration and the VSWR, switching time, and dielectric withstanding voltage test values shall meet the original parameters. 3.5 Reliability. When tested as specified in 4.7.20, the switch shall provide a minimum acceptance mean time between failures (MTBF) of 1,000 hours.
45、 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-25879G 7 3.6 Marking (see 3.1). Switches shall be marked in a legible and permanent manner with the following information. a. The RF connections shall be identified as shown on figure 1. b. Min
46、imum marking shall include the following: (1) Name: Switch, RF transmission line. (a) Part or Identifying Number (PIN): Type SA-521A/A. (b) Voltage: 28 V dc maximum. (c) Contract number: As assigned by acquiring agency. (d) Manufacturer CAGE code. The marking shall remain legible after completing al
47、l environmental tests. 3.7 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or environmentally preferable materials should be used to the maximum extent possible, provided that the material meets or exceeds the operational and maintenance requirements, and promotes
48、economically advantageous life cycle costs. 3.8 Workmanship. Switches shall be manufactured and processed in a careful and workmanlike manner, in accordance with good design and sound engineering practice, and to the requirements of this specification. For guidance on workmanship see 6.7. 4. VERIFIC
49、ATION 4.1 Classification of inspections. The inspections specified herein are classified as follows: a. Materials inspection (see 4.2). b. First article inspection (see 4.4). c. Conformance inspection (see 4.5). 4.2 Materials inspection. Materials inspection shall consist of certification supported by verifying data (see 6.3) that the m
