Coaxial/TwinAxial Cable- RG 8/U

RG 8/U coaxial cable is commonly used for 50-ohm RF signal transmission in applications such as broadcast systems, amateur radio, MATV, CATV, and certain local area network installations.

Its relatively large conductor and overall cable diameter make it well suited for applications where dependable RF performance and lower signal loss over longer cable runs are important. The specific RG 8/U construction should still be matched to the equipment, frequency range, connectors, and installation environment.

RG 8/U uses a nominal 50-ohm impedance because 50 ohms is widely used for RF transmission systems that require a balance between power handling and signal performance.

Maintaining the correct impedance throughout the cable, connectors, and connected equipment helps minimize reflected signals and transmission losses. RG 8/U should therefore be used in systems designed for 50-ohm coaxial cable rather than substituted for 75-ohm or 93-ohm coax.

The insulation construction affects the cable's capacitance, signal velocity, and overall electrical performance.

RG 8/U constructions with solid polyethylene on this page have a nominal velocity of propagation of 66%, while cellular polyethylene versions are rated at 78%. The semi-solid polyethylene construction reaches 84%. These differences can matter when propagation speed, capacitance, timing, or RF performance must meet specific system requirements.

A combination foil-and-braid shield can provide more complete shielding coverage than a braid alone, helping reduce the effect of electromagnetic and radio-frequency interference on the transmitted signal.

One RG 8/U construction offered here combines 100% bonded foil coverage with an 88% tinned copper braid. Other versions use bare copper braid coverage ranging from 93% to 97%. The appropriate shield design depends on the level of interference protection, flexibility, grounding, and installation characteristics required.

Choose an RG 8/U construction by comparing conductor size and stranding, insulation type, shield design, jacket material, capacitance, velocity of propagation, and the requirements of the equipment being connected.

Although the RG 8/U products on this page all have a nominal 50-ohm impedance and approximately 0.405-inch outside diameter, their internal constructions differ significantly. Available designs include solid and stranded bare copper conductors, solid, semi-solid, or cellular polyethylene insulation, different braid coverage levels, and PVC or polyethylene jackets. Selecting by the complete specification rather than the RG designation alone helps ensure the cable performs correctly in the intended application.