Word to the wise - coax conductor migration.

All coax is not created equal

Word to the wise – coax conductor migration.

Conductor Migration occurs when the center conductor of a coaxial cable moves away from the desired centered position in the cable geometry. Certain types or qualities of coaxial cable or coaxial connectors can fail to maintain a consistent distance between the inner conductor and the outer shield when subject to mechanical and/or thermal stresses beyond their design ratings.

Beyond presenting non-uniform impedance, should the center conductor actually touch the shield, an arc or short could occur. Good practice in using coaxial cable includes paying attention to minimum bend radius specifications, and avoiding foam-filled insulation types for physically demanding applications.

For long service life, use good-quality coaxial connectors – some very inexpensive connectors have been found to use plastics that can melt or deform even while soldering.

(Original story source:  arrl.org)

P.S. Long ago I learned not to skimp on coax and connectors. I use the good stuff, Times Microwave. Yes, it costs more but it’s worth it.

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