Connector anatomy
BNC
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01
Centre conductor
Carries the video signal — the copper wire at the very core of the coaxial cable.
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02
Bayonet lock
Push and give it a quarter turn to lock. That is what keeps a camera connected on a pole in the wind.
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03
Braided shield
The copper braid surrounds the core and holds the cable's impedance constant along the whole run (50 or 75 ohm, depending on the cable).
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04
50Ω vs 75Ω
BNC connectors come in two incompatible impedances: 50 ohm (RF/data standard) and 75 ohm (video/broadcast standard). Mixing them causes real signal loss (about 5% per mismatch point) — a common mistake when a 50 ohm BNC cable ends up on a 75 ohm CCTV run.
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05
Strain-relief boot
Stops the wires flexing where they leave the plug — the exact point most cables fail.
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06
Outer jacket
The outer sheath protecting the conductors inside from abrasion and moisture.
Technical illustration, not a photo of the actual product