MIL-DTL-49295C
4.9 Mechanical tests.
4.9.1 Performance of test. Every joint, screw, seam, gasket, and any other area where two pieces interface on the
balun housing subassembly half of the matching transformer shall be thoroughly painted with a soap and water
solution. Without touching the painted half, carefully place the matching transformer into the vacuum chamber in a
manner that will allow close visual examination of the painted portion while the vacuum chamber is being operated.
While the balun housing subassembly is still wet from the painted soap and water solution, a vacuum of 2.5 psig shall
be applied to the chamber interior. While the vacuum is being maintained, there shall be no leaks, as evidenced by
bubbling or sputtering of the wet solution. If there is a leak(s), rework shall be accomplished. Detection of a leak(s)
at this stage shall be considered as having failed this test. The reworked area(s) shall then be re-inspected in
accordance with standard industry practice.
4.9.2 Housing plate assembly. The matching transformer shall be placed in a position that allows access to all
exterior joints and fasteners on the housing plate assembly surface and shall be tested as follows.
4.9.2.1 Performance of test. Every joint, screw, seam, gasket, and any other area where two pieces interface on
the housing plate assembly half of the matching transformer shall be thoroughly painted with a soap and water
solution. Without touching the painted half, carefully place the matching transformer into the vacuum chamber in a
manner that will allow close visual examination of the painted portion while the vacuum chamber is being operated.
While the housing plate assembly is still wet from the painted soap and water solution, a vacuum of 2.5 psig shall be
applied to the chamber interior. While the vacuum is being maintained, there shall be no leaks, as evidenced by
bubbling or sputtering of the wet solution. If there is a leak(s), rework shall be accomplished. Detection of a leak(s)
at this stage shall be considered as having failed this test. The reworked area(s) shall then be reinspected in
accordance with 4.9.2.
4.10 Environmental tests. The antenna system shall be subjected to the environmental tests specified below.
Prior to each test, the test items shall be subjected to the free space VSWR test (see 4.5.1.1) and shall meet the
requirements of 3.4.2.4. Immediately after exposure to each environmental test specified below the test items shall
be subjected to the following inspections: RF power level of 4.5.1.2; dielectric withstanding voltage of 3.4.2.9; free
space VSWR of 4.5.1.1; and service conditions of 3.5. Specific tests may be waived, with Government approval, for
those items which have previously been qualified.
4.10.1 Temperature. The antenna shall be subjected to the following temperature tests.
4.10.1.1 High temperature. The antenna system shall be subjected to the test of method 501.5, procedure II of
MIL-STD-810. At steps 4 and 7, the chamber temperature shall be 71°C (+160°F). During step 8, the matching
transformers shall be subjected to the matching transformer power test, 4.5.1.3, for one hour. During the test all
items of the antenna system shall be stowed in the bag except for the matching transformer. After exposure, the
tests of 4.5 shall be conducted. When any combination of high temperature, low temperature and immersion are
done on the same sample, 4.5.3 need only be done once after completion of these tests (see 3.5.1a, table IV).
4.10.1.2 Low temperature. The antenna system shall be subjected to the test of method 502.5, procedure I of
MIL-STD-810. During step 2, the chamber temperature shall be maintained at -57°C (-70°F) for not less than 2 hours
after stabilization of the test items. Delete step 3. During step 4, the chamber temperature shall be maintained at
-45.6°C (-50°F) for not less than 4 hours after stabilization of the test items. During step 5, the matching transformers
shall be subjected to the matching transformer power test 4.5.1.3 for one hour. During the test all items of the
antenna system shall be stowed in the bag, except for the matching transformer. After exposure, the tests of 4.5
shall be conducted. When any combination of high temperature, low temperature and immersion are done on the
4.10.2 Dust. The antenna system shall be subjected to test method 510.5, procedure I of MIL-STD-810.
Operation is not required during the test. The antenna system shall be tested in accordance with 4.5.1 following this
4.10.3 Salt fog. The antenna system shall be subjected to test method 509.5 of MIL-STD-810. Mechanical failure
criteria shall be limited to corrosion of finishes and metals only. Such corrosion shall be defined as any visible
degradation of the equipment surfaces that can be attributed to flaky, pitted, blistered, or otherwise loosened finish on
metal surfaces (see 3.5.5, table IV).
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