MIL-DTL-25708F
4.5.7.7 Fungus (see 3.5.7). The manufacturer shall certify that all materials are fungus resistant or perform the test
specified in MIL-STD-810 method 508.
4.5.7.8 Salt fog (see 3.5.8). MIL-STD-810 method 509, in accordance with test apparatus and procedures detailed
in method 509, section II, including procedure I. The following details shall be specified in the equipment
specification:
a.
Pretest data required.
b.
Failure criteria.
c.
Applicable salt solution, if other than 5 percent.
d.
Salt fog exposure period, if other than 48 hours.
e.
Drying period, if other than 48 hours.
f.
Inspection and operation after 24 hours of salt fog exposure where buildup of salt deposits are critical to the
proper operation of the test item.
g.
If operation of electrical system is required.
4.6 Seal test (see 3.4.3). All samples shall be subjected to seal test by altitude chamber method. The antennas
shall be fully submerged in a water-filled, transparent container. The test antenna connectors may be covered with a
mating cap simulating the mating connection. The chamber shall be evacuated to a pressure 1.06 inches of mercury
simulating an altitude of 75,000 feet and remain there for a minimum of 5 minutes. The chamber pressure shall then
be raised to 2.5 inches of mercury simulating an altitude of 57,000 feet and maintained at that condition for a minimum
of 10 minutes. Then the chamber pressure shall be raised to standard atmospheric pressure for 1 hour. Upon seal
test completion, antennas shall be removed and all excess moisture wiped from the antenna. Any evidence of
leakage either by a flow of bubbles during evacuation or subsequent entrance of water shall be considered a failure.
Immediately after examination, the antenna shall meet the requirements of the impedance test (see 4.5.2) and of the
4.7 Static load test (see 3.4.4). A static load as specified in accordance with the specification sheet (see 3.1), shall
be imposed on the antenna. The antenna shall be normally mounted on a fixture and an air bladder draped on one
side similar to figure 3. The bladder shall then be inflated until it is just making contact with the antenna surface. An
air pressure reading shall then be taken and the internal air pressure shall then be increased to the specified pressure
in accordance with the applicable specification sheet (see 3.1) and held for 5 minutes. The pressure shall then be
released and the same procedure repeated on the opposite side. This shall be considered as one cycle. The test
shall be two cycles in duration. Upon completion of the second cycle, the antenna shall be removed and carefully
examined for deformation and structural failure. Impedance test (see 4.5.2) shall be made and VSWR shall be as
specified in the applicable specification sheet (see 3.1).
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