RF Coax Cable Types & Data

- table data including size, impedance, loss propagation constant, etc for the more commonly used types of RF coax cable.

Coax cable tutorial includes:

    •  Coaxial feeder overview
    •  Coax specifications
    •  Coax impedance
    •  Loss or attenuation
    •  Coax power rating
    •  Coax velocity factor
    •  Coax environmental factors
    •  Coax types & data
    •  Coaxial installation tips

There is a variety of different types of coax or coaxial cable that are in widespread use. Different types of coax cable or feeder are needed for different purposes and applications and accordingly it is necessary have specifications and data to be able to determine the required coax type or RF cable type easily.

While it would be possible to manufacture an infinite variety of RF cables, standard varieties are specified. There are two basic systems that are used for defining RF cables. One originated in the United Kingdom and its type numbers all start with UR. The other system is American with type numbers commencing with the letters RG.

The RG series was originally used to specify the types of coax cables for military use, and the specification took the form RG (RG from Radio Guide) plus two numbers. In some instances these numbers were followed by the letter U which indicated it was for multiple uses. These types of coax cable were all listed in the MIL-HDBK-216 which is now obsolete. Although full MIL specifications are now officially used for specifying most components for military use, the RG series of RF cables continued to be used because of its widespread acceptance. However it should be noted that the RG specifications are no longer maintained so there is no complete guarantee to the exact specification for the particular type of coax cable.

A summary of data for some of the more commonly used types of coax or coaxial cable is given below. Most of these RF cables are easily available from RF cable stockists.:

Data for attenuation figures are typical figures and measured in dB / 10 metres             dimensions in mm

The RF cables described above are all flexible cable types. For microwave applications where very low loss is needed, semi rigid coaxial RF cable using a solid copper outer sheath may be used. This type of coax offers superior screening compared to RF cables with a braided outer conductor, especially at microwave frequencies. As the name implies, though, it is not particularly flexible and is not intended to be flexed after it has been formed to the required shape.

This RF cable data has been presented as a guide and no liability can be taken for any errors or mistakes in the data. Naturally every care has been taken to ensure the data concerning these RF cables is correct.

By Ian Poole

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