HD-SDI cable selection and signal integrity on camera rigs

Gear

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2012Brackets/Widgets forum

14 years old. Gear and prices may have changed since.

DisputedParticipants disagreed and reached no conclusion. Read the findings as positions, not as an answer.

Belden 9221 miniature coax cable with proper 75-ohm impedance can be used effectively for short HD-SDI runs on camera sleds without signal degradation when properly terminated with true 75-ohm connectors.
Each connection point (barrel connectors, T-adapters, 90-degree adapters) in an HD-SDI signal chain introduces impedance mismatches that degrade signal quality, and HD-SDI signals fail completely rather than gracefully degrading when fidelity drops below minimum threshold.
Belden 1694A cable with 18 AWG solid core construction is considered optimal for HD-SDI applications due to superior shielding compared to thinner stranded options.
True 75-ohm BNC connectors can be identified by checking whether the internal tubular pin is fully supported with plastic material all the way up.
Over short distances typical on camera rigs, properly made and impedance-matched cables of different quality levels perform similarly, with cable length becoming the primary factor affecting signal loss rather than cable type.
Using thin BNC cables bundled alongside power cables and other signal types has been reported without interference problems when cables are properly constructed.
50-ohm cables should not be used for HD-SDI applications, and some 50-ohm inventory has entered video departments from audio and computer networking sources where it was originally specified for different purposes.

The discussion primarily addresses short cable runs typical of camera rig setups, not long-distance HD-SDI transmission.
Practical experience comes from film production contexts; applicability to other HD-SDI applications may vary.
No controlled testing or measurements were provided to quantify performance differences between cable types.
The claim that thin spaghetti cables are adequately shielded for HD-SDI when properly made is contradicted by another participant's concern about insufficient shielding despite 75-ohm rating.