MIL-DTL-28781E
TABLE IX. Reinspected lots.
Number of pairs in
Sample
Sample size
assembled cable
First
1
1
Second
1
First
2
3
Second
2
First
2
6
Second
2
First
3
16
Second
3
First
3
26
Second
3
First
3
52
Second
3
4.6 Methods of inspection.
4.6.1 Visual and dimensional examination. Finished wire shall be examined to determine that the
materials, physical dimensions, construction, splices, marking, and workmanship conform to the
applicable requirements. The color coding, shielding, core covering, binder marking, pair twist rate, cable
forming, and jacket thickness shall be examined at the ends of the shipping length of cable on the reel.
The cable shall be examined for jacket imperfections on all of the surface which is visible without
unwinding the cable from the reel.
4.6.2 Mutual capacitance test. The mutual capacitance test shall be performed on the cable shipping
length in place on the reel. Mutual capacitance is the effective capacitance between the two wires of a
pair. Mutual capacitance may be measured on individual pairs, or the average mutual capacitance may
be on a number of pairs in groups. The mutual capacitance shall be measured by using a suitable
capacitance or impedance bridge with a test frequency of 1,000±100 Hz. Where group measurements of
mutual capacitance are performed with cables exceeding 26 pairs in size, these measurements should be
made on individual groups rather than on all pairs of the cable grouped together for a single average
measurement. In any reel of 12 pairs or more, the rms deviation of mutual capacitance of all the pairs
tested from the average mutual capacitance of that reel shall not exceed four percent.
4.6.3 Capacitance unbalance test. The capacitance unbalance test shall be performed on the cable
shipping length in place on the reel.
4.6.3.1 Pair-to-pair capacitance unbalance. The capacitance involved and test methods are shown
on figure 1. One and two represent the two conductors of a pair. Three and four represent the two
conductors of a second pair. The capacitances, namely C13, C14, C23, C24, C12, and C34 are the direct
capacitances between conductors.
The capacitances C1g, C2g, C3g, and C4g are the direct capacitances between wires 1 through 4,
respectively, and all other conductors in the cable connected to the shield and ground. The pair-to-pair
capacitance unbalance is: (C14 + C23) - (C13 + C24)
13
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business