What are RG165 Coaxial Cables?

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- everything RF

Jan 19, 2023

RG165 Coaxial Cables are a type of cable that is commonly used for telecommunications and networking applications. These cables are ideal for carrying radio frequency (RF) signals over longer distances due to their lower signal attenuation and high degree of signal integrity.


The RG165/U is a 50-ohm coaxial cable with an overall diameter of 0.410 inches and a voltage rating of up to 5000 Vrms. It has an inner silver-covered copper (SC) wire (carrying the electrical signal) with 7x20 stranding construction. The inner conductor is enclosed by an insulation layer made of Polytetrafluoroethylene (PTFE). The insulation layer is then completely enclosed by 1 silver-covered copper (SC) 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 FG-V. The jacket protects the cable core from mechanical, moisture, and chemical issues.

The RG165/U cable exhibits capacitance of approximately 29 pF/ft (95.39 pF/m), and signal attenuation of around 5.0 dB/100 ft at 400 MHz (signal attenuation of the cable depends on the frequency). It has a center conductor measuring 0.0960 inches (2.43 mm) in diameter and an insulation layer measuring 0.285 inches (7.2 mm) in diameter.

Key Specifications of RG-165/U Coaxial Cables


Typical Value

Overall Diameter (inch)


Characteristic Impedance (Zo)

50 ohms

Maximum Voltage Rating (RMS)

5000 V

Cable Capacitance (pF/ft)


Attenuation (dB/100 ft, @ 400 MHz)



Polytetrafluoroethylene (PTFE)

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