MIL-DTL-287J
d. Measurements after test: Insertion loss, stability of insertion loss, and VSWR shall be measured as
4.7.12 Thermal shock. Assemblies shall be tested in accordance with MIL-STD-202, method 107 (see 3.5.11).
The following details and exception shall apply:
a. Special mounting: Not applicable.
b. Test condition letter: A.
c. Measurements before test: Not applicable.
d. Measurements after test: Pressurization, insertion loss, and VSWR shall be measured as specified in
4.7.13 Power handling capability (when specified, see 3.1). Assemblies shall be subjected to the RF power level
specified (see 3.1) at the frequency, simulated altitude and temperature specified (see 3.1 and 3.5.12). Power shall
be maintained for a period of 1 hour after the temperature of the assembly has reached equilibrium. This condition
is reached when the assembly temperature shall not vary more than 5°C within a 15-minute period. During the test,
the assembly shall be terminated in a suitable load. After the test, insertion loss and VSWR shall be measured as
4.7.14 Bending test. One end of the assembly shall be firmly fixed to a stationary platform, and a guide or
mandrel having a set radius of curvature for the assembly to be tested shall be attached on the same end. The
assembly shall be mounted in a straight position in such a manner that it will be neither tension nor compression.
An even and smooth oscillating motion shall then be applied to the free end so that the portion near the fixed end
will bend around the mandrel. The assembly shall be bent to one side of the relaxed position to the centerline radius
and in the planes specified (see 3.1). An appropriate length shall be used which will allow the bend to be
accomplished in one revolution or less. The centerline of the assembly shall be normal to the stationary platform
when in the relaxed position. The assembly shall be subjected to five complete cycles of bend in each plane from
the relaxed position in each plane. One cycle is completed when the assembly is bent from the relaxed position to
the specified bend and back to the relaxed position. The stability of insertion loss and the VSWR shall then be
4.7.15 Flexure. The method of flexure testing shall be as follows using the test machine as shown on figure 3.
For assemblies that operate up to 12.4 GHz inclusive, a 24 inch (610 mm) (nominal) long representative sample of
the same size and type as the assembly under test may be used for the flexure test. For assemblies that operate
above 12.4 GHz and through 26.5 GHz, a 12 inch (305 mm) (nominal) long representative sample of the same size
and type as the assembly under test may be used for the flexure test. For assemblies that operate above 26.5 GHz,
a 2 inch (51 mm) (nominal) long representative sample of the same size and type as the assembly under test may
be used for the flexure test. The pivot point of the test machine shall be located under the geometrical center of the
waveguide in the relaxed position as shown on figure 3. The stationary end of the waveguide shall be rigidly
secured to an adapter which is motionless throughout the test. A wooden form shall be used to assure that the test
sample will take the intended bend. Enough tension shall be applied to cause the test sample to take the radius of
the wooden form and return to the straight condition on the reverse stroke. The moving end of the machine shall
contain an adapter which will allow the flexed end of the waveguide to move in the radial direction. The apparatus
shall be set for the desired flexure angle and a counter shall be installed to record the number of cycles. The planes
of bending, the angle of bending, and the number of cycles shall be as specified (see 3.1). This bend shall be in two
directions, 50 percent of the angle on one side of the relaxed position and 50 percent of the angle on the opposite
side of the relaxed position. The cycling rate shall be 30 cycles per minute minimum. The stability of insertion loss
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