What are RG122 Coaxial Cables?

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- everything RF

Jan 18, 2023

RG122 Coaxial Cables are a type of cable that has been designed for high frequency signal transmission. They exhibit high signal integrity and low signal attenuation making them ideal for long-range communication and networking applications.


RG122/U Cable Construction, Image Credit: Pasternack EnterprisesThe RG-122/U is a 50-ohm coaxial cable with an overall diameter of 0.160 inches and a voltage rating of up to 1900 Vrms. It has inner tinned copper wires (carrying the electrical signal) with 27x36 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 or bare copper braid shield that forms the outer conductor and also provides shielding against electromagnetic interference (EMI). Finally, the structure is covered with an outermost layer - called a jacket - made of Polyvinyl Chloride (PVC) or XL polyolefin. The jacket protects the cable core from mechanical, moisture, and chemical issues.

The RG122/U cable exhibits capacitance of approximately 31 pF/ft (101.9 pF/m), and signal attenuation of around 18 dB/100 ft at 400 MHz (signal attenuation of the cable depending on the frequency). It has a center conductor measuring 0.030 inches (0.762 mm) in diameter and an insulation layer measuring 0.096 inches (2.43 mm) in diameter.

Key Specifications of RG-122/U Coaxial Cables


Typical Value

Overall Diameter (inch)


Characteristic Impedance (Zo)

50 ohms

Maximum Voltage Rating (RMS)

1900 V

Cable Capacitance (pF/ft)


Inductance (nH/ft)


Attenuation (dB/100 ft, @ 400 MHz)



Polyethylene (PE)

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