What are RG131 Coaxial Cables?

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- everything RF

Jan 18, 2023

RG131 coaxial cables are an essential component in many electronic and networking systems applications. They offer high signal integrity and low loss of transmission, making them suitable for long haul communication links. With a durable and flexible design, RG131 coaxial cables are a reliable choice for both indoor and outdoor use.


The RG-131/U is a 95-ohm coaxial cable with an overall diameter of 0.683 inches and a voltage rating of up to 3000 Vrms. It has two inner bare copper wires (carrying the electrical signal) with a 7 x 21 stranding construction. The inner conductors are enclosed by an insulation layer made of Polyethylene (PE). The insulation layer is then completely enclosed by 1 tinned copper braid shield that forms the outer conductor and also provides shielding against electromagnetic interference (EMI). The shield layer is then covered by a layer- called a jacket - made of Polyvinyl Chloride (PVC). The jacket protects the cable core from mechanical, moisture, and chemical issues. Finally, the structure is covered with an outermost layer-called armor. The armor is made of an aluminum braid and offers extra mechanical protection to the cable. 

The RG131/U cable exhibits capacitance of approximately 17 pF/ft (55.92 pF/m), and signal attenuation of around 8.8 dB/100 ft at 400 MHz (signal attenuation of the cable depending on the frequency). It has the center conductor measuring 0.0855 inches (2.17 mm) in diameter and an insulation layer measuring 0.472 inches (11.98 mm) in diameter.

Key Specifications of RG-131/U Coaxial Cables


Typical Value

Overall Diameter (inch)


Characteristic Impedance (Zo)

95 ohms

Maximum Voltage Rating (RMS)

3000 V

Cable Capacitance (pF/ft)


Attenuation (dB/100 ft, @ 400 MHz)



Polyethylene (PE)

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