Balanced BNC cables

balancingbnccoaxinterference

I'm working in an experiment with high voltages and unfortunately a high voltage AC source is affecting the signal in my BNC coaxial cable (which is going into an oscilloscope or some other measuring device). Is there an easy or standard way to implement balancing as in audio XLR cables?

Best Answer

One way (imo, it could be considered standard) exists:

1) replace your coax cable with a twinax double shielded cable

2) terminate the cable at both sides by a BNC styled twinax connector

  • various types exist, 3-lag, "hermafrodite", etc... select available one
  • connect the first cable shield to (only) one side connector, the second shield to (only) another side connector

3) use BNC twinax adapters to properly ground the shields and comfortably interface with normal BNC equipment

As stated here, "Other authors have concluded that two braided shields can help to reduce noise coupling by 20 to 30 dB."