What are RG304 Coaxial Cables?

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- everything RF

Jan 30, 2023

RG304 Coaxial Cables are a type of cable typically used for high frequency signal transmission. They exhibit high degree of signal integrity and feature low signal loss, making them ideal for long-haul communication links and networking applications.


RG304/U Cable Construction

The RG304/U is a 50-ohm coaxial cable with an overall diameter of 0.280 inches and a voltage rating of up to 3000 Vrms. It has an internal silver-covered copper-clad steel (SCCS) conductor (carrying the electrical signal), which is enclosed by an insulation layer made of Polytetrafluoroethylene (PTFE). The insulation layer is then completely enclosed by 2 silver-covered copper braid shields that form the outer conductor and also provide shielding against electromagnetic interference (EMI). Finally, the structure is covered with an outermost layer - called a jacket - made of Fluorinated ethylene propylene (FEP-IX). The jacket protects the cable core from mechanical, moisture, and chemical issues.

The RG304/U cable exhibits capacitance of approximately 29.4 pF/ft (96.5 pF/m), signal attenuation of around 6.0 dB/100 ft at 400 MHz (signal attenuation of the cable depending on the frequency), and has a velocity of propagation of 70%. It has a center conductor measuring 0.059 inches (1.49 mm) in diameter and an insulation layer measuring 0.185 inches (4.69 mm) in diameter. This cable is ideal for use in aerospace & defense for data transmission in extreme conditions. It has an operating temperature of -55˚C to + 200˚C.

Key Specifications of RG304/U Coaxial Cables


Typical Value

Overall Diameter (inch)


Characteristic Impedance (Zo)

50 ohms

Maximum Voltage Rating (RMS)

3000 V

Cable Capacitance (pF/ft)


Attenuation (dB/100 ft, @ 400 MHz)



Polytetrafluoroethylene (PTFE)

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