Coaxial/TwinAxial Cable- RG 59/U and RG 59 B/U

RG 59/U and RG 59 B/U coaxial cables are commonly used to transmit radio frequency and video signals in systems that require a compact coaxial construction. The cables on this page are suitable for applications such as master antenna television systems, local area networks, citizen band radio equipment, cathode-ray-tube equipment and other RF signal transmission installations.

The correct cable depends on the required impedance, shielding, insulation and applicable electrical standard. Although RG 59 is widely associated with 75-ohm video systems, the available constructions on this page include nominal impedance ratings of 73, 75 and 80 ohms. The cable should therefore be selected according to the electrical requirements of the equipment rather than by the RG designation alone.

The available RG 59/U and RG 59 B/U cables differ in conductor size, insulation type, shielding method, impedance, capacitance, velocity of propagation and regulatory designation. Some constructions use a solid polyethylene insulation core, while others use cellular polyethylene. Shielding options include a 95% bare copper braid or a combination of 100% aluminum Mylar tape and an aluminum braid.

For example, Item 359B is a 75-ohm MIL-C-17D construction with a 23 AWG solid bare Copperweld conductor and 95% bare copper braid. Other options are rated as NEC Type CL2, UL Style 1354 or AWM 1354. Reviewing these individual specifications is important because two cables carrying an RG 59 designation may not provide identical electrical performance or installation compliance.

Choose a cable with a nominal impedance that matches the transmitter, receiver, connector and other components in the signal path. An impedance mismatch can cause signal reflections, increased loss and reduced system performance. Many video and broadcast systems use 75-ohm coaxial cable, but the products listed here also include 73-ohm and 80-ohm constructions for equipment requiring those values.

Do not select a cable based only on its RG 59/U or RG 59 B/U name. Confirm the required impedance in the equipment documentation and compare it with the specifications for the individual cable item. Connector impedance should also match the cable and connected equipment whenever possible.

The shield helps prevent external electromagnetic interference from entering the cable and limits signal energy from escaping. The RG 59 constructions on this page are available with either a 95% bare copper braid or a foil-and-braid shield. The foil-and-braid versions use 100% aluminum Mylar coverage combined with either 40% or 67% aluminum braid coverage.

A copper braid provides strong mechanical durability and effective shielding across a broad frequency range. A foil shield provides complete physical coverage, while the additional braid improves grounding continuity and handling strength. The most suitable construction depends on the expected interference, operating frequency, cable movement, grounding method and connector requirements.

Nominal capacitance indicates how much electrical charge the cable stores per foot and can influence signal loading, rise time and performance over longer runs. The cables on this page range from approximately 16.0 to 20.7 picofarads per foot. Lower capacitance may be beneficial in applications where preserving signal timing and reducing electrical loading are important.

Velocity of propagation describes how quickly a signal travels through the cable compared with the speed of light. The available constructions are rated at either 66% or 78%. Cellular polyethylene insulation generally provides the higher propagation velocity, while solid polyethylene versions on this page are rated at 66%. Engineers should evaluate both specifications when cable length, signal timing or frequency performance is critical.