MIL-PRF-39012E
To measure VSWR several sweeps are made with the slotted line probe incrementally positioned
over at least a half wave length at the lowest frequency of interest. In this manner an X-Y display is
generated whose upper and lower envelope limits represent maximum and minimum amplitudes of
the standing wave for each frequency in the test band. A base line may be generated by making a
sweep with no input to the measurement channel amplifier. The resultant X-Y display is calibrated
according to the characteristics of the measurement channel detector and amplifier, e.g., linear,
square law, logarithmic, etc .
The VSWR test system is checked out successively terminating the slotted line with the elements
shown in steps 1 and 2 and sweeping the frequency over the specified test band (see 3.1). In step 1
the system VSWR shall be less than 1.02 + .004 F (F measured in GHz). In step 2, the system
VSWR shall be as specified (see 3.1).
For qualification and group C inspection (see tables II and VII), the system is checked out with the
slotted line terminated as in step 3 using the specified cable (see 3.1). The impedance variation
(random and/or periodic) from the nominal characteristic impedance specified for the selected test
cable should be no more than 1.0 percent when tested by time domain reflectometry. In step 3, the
system VSWR shall be as specified (see 3.1). For qualification and group C inspection, the
connector under test is measured with the slotted line terminated as in step 4. The VSWR shall be
as specified (see 3.1).
Group B inspection tests (see table V) are performed with the slotted line terminated as shown in
step 7. The input part of the cable simulator must have the same interface configuration,
dimensions, and dielectric as the recommended cable interface for the connector under test. The
cable simulator for group B inspection tests must meet the specified VSWR (see 3.1) when tested as
shown in step 6.
The standard precision adapter interface shall conform to IEEE Standard 287. Item 6 (standard
precision adapters) shall not exceed the specified VSWR requirements (see 3.1). Standard test
adapter designs shall be approved by the military qualifying agency.
4.6.12 Connector durability (see 3.15). Each connector under test shall be mated with a typical
production connector in accordance with this specification. The connector shall be subjected to the
number of cycles of mating and unmating specified (see 3.1). The connector and its mating part shall
be completely engaged and completely disengaged during this cycle. Lubrication of the threads or
rotational parts shall not be employed for this test unless specified (see 3.1). It is permissible to
shake or blow debris from the threads or interface surfaces at intervals of not less than 50 cycles.
Solvents or tools shall not be used for cleaning.
18
For Parts Inquires submit RFQ to Parts Hangar, Inc.
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business