MIL-DTL-25708F
Step 11. With test item de-energized, adjust chamber temperature to step 11 conditions. The antenna
temperature shall be stabilized and the antenna energized at the highest specified input voltage,
while chamber pressure is adjusted to simulate step 11 altitude. The antenna shall be operated
for 4 time periods each of 30 minutes. The first three time periods of operation shall be followed
by 15 minutes of operation, followed by a 15 minutes with the antenna de-energized. The test
item shall be checked for satisfactory operation during each operating time period. Thermal
sensor readings of antenna temperature shall be recorded every 10 minutes of antenna operation.
Step 12. With the antenna de-energized, adjust chamber temperature to step 12 conditions (following steps
where a change in temperature at low pressure is required, the pressure may be increased to
ambient before changing temperature and then returned to the required pressure following
temperature stabilization.) The antenna temperature shall be stabilized and the antenna shall be
energized at the highest specified input voltage and chamber pressure adjusted to step 12
conditions. Maintain for step 12 duration. Thermal sensor readings of antenna temperature shall
be recorded every 30 minutes. At end of 4 hours, while maintaining test conditions, check
antenna for satisfactory operation.
Step 13. With the antenna de-energized, adjust the chamber temperature to step 13 conditions and
maintain. The antenna temperature shall be stabilized. The antenna shall be energized at the
highest specified input voltage and the chamber pressure adjusted to step 13 altitude. The
antenna shall be operated for four time periods de-energized. The antenna shall be checked for
satisfactory operation during each operating period of 30 minutes. The first three time periods
shall be followed by a 15-minute period with the antenna. Thermal sensor readings shall be
recorded every 10 minutes of antenna operation.
Step 14. With antenna de-energized, adjust chamber temperature to step 14 conditions (following steps
where a change in temperature at low pressure is required, pressure may be increased to ambient
before changing the temperature and then returned to the required pressure following temperature
stabilization) and maintain. Antenna temperature shall be stabilized. The antenna shall be
energized at the highest specified input voltage and chamber pressure adjusted to step 14
altitude. The antenna shall be operated four time periods each of 10-minute duration and shall be
followed by a 15-minute period with the antenna de-energized. The antenna shall be checked for
satisfactory operation during each operating period. Thermal sensor readings of antenna
temperature shall be recorded at the beginning and end of each operating time period.
Step 15. Adjust chamber test conditions to standard ambient. After the antenna temperature has stabilized,
an operational and performance check of the antenna shall be made. Results shall be compared
with performance before temperature-altitude test.
4.5.7.3 Temperature shock (see 3.5.3). Test in accordance with MIL-STD-810 method 503 using the following
procedure:
Step 1: Prepare the antenna and raise chamber temperature to 65.4°C (150°F). Maintain for a period of not
less than 4 hours or until the antenna temperature stabilizes.
Step 2: At the conclusion of this time period, transfer the antenna, within 5 minutes, to a cold chamber with
internal chamber temperature stabilized at -57°C (-70°F).
Step 3: The antenna shall be exposed to the step 2 temperature for a period of not less than 4 hours or until the
antenna temperature stabilizes.
Step 4: At the conclusion of this time period, the antenna shall, within 5 minutes, be returned to the high
temperature chamber maintained at 65.4°C (150°F).
Step 5: The antenna shall be exposed to this high temperature for a period of not less than 4 hours or until the
antenna stabilizes at chamber temperature.
Step 6: Repeat steps 2 through 5.
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