Key Considerations When Selecting Double-Shielded Coaxial Cables
Double-shielded coaxial cables offer enhanced protection against electromagnetic interference (EMI) and radio frequency interference (RFI) compared to their single-shielded counterparts. They are crucial for applications where signal integrity is paramount, such as high-performance audio and video systems, data networks, and telecommunications.
When selecting double-shielded coaxial cables, several key considerations come into play:
Shield Construction
The shield is the primary defense against EMI and RFI. Construction materials, such as braided copper, aluminum, or foil, determine its effectiveness. Braided shields provide superior EMI protection but are less flexible. Foil shields, on the other hand, are more flexible but less effective at shielding against high-frequency interference.
Shielding Effectiveness
Shielding effectiveness is measured in decibels (dB) and indicates the cable’s ability to block unwanted signals. Higher dB ratings indicate better shielding. For critical applications, cables with shielding effectiveness of 100 dB or higher are recommended.
Conductor Material
The conductor material determines the cable’s electrical characteristics. Copper is the most common conductor material, offering excellent conductivity and signal integrity. Silver-plated conductors enhance signal transmission speed and reduce losses.
Conductor Size
Conductor size, measured in American Wire Gauge (AWG), affects cable resistance and signal loss. Thicker conductors (lower AWG numbers) have lower resistance and can carry higher currents, resulting in better signal transmission.
Insulation Type
Insulation material isolates the conductor and shields the cable from external influences. Common insulation materials include polyethylene (PE), polytetrafluoroethylene (PTFE), and foamed polyethylene (FPE). FPE offers excellent dielectric properties and flexibility, while PTFE provides superior heat resistance.
Jacket Material
The jacket protects the cable from environmental factors, such as moisture, UV radiation, and physical damage. PVC jackets are commonly used for indoor applications, while polyethylene jackets are suitable for outdoor use due to their enhanced UV resistance.
Flexibility
Flexibility is an important consideration for cables that need to be bent or routed around obstacles. Double-shielded cables with a high degree of flexibility can withstand repeated flexing without compromising performance.
In addition to these technical considerations, the required length, connectors, and the specific application should also be taken into account when selecting double-shielded coaxial cables. By considering these key factors, engineers and installers can ensure they choose the optimal cables for their specific needs, maximizing signal integrity and minimizing interference.