Coaxial and RF cable

What an RG number does and does not say

RG numbers come from an American military nomenclature and survived as trade names. An RG number on its own says little. Only the MIL-C-17 designation, such as M17/74-RG213, fixes impedance, dielectric, braid coverage and tolerances. Our RG 213 and RG 214 TY-ZH follow that construction as commercial versions, without an M17 number of their own.

The four 50 ohm types differ in size and screening. RG 58 is thin and flexible for short connections. RG 213 is thicker with lower attenuation. RG 214 has two silvered braids for higher screening effectiveness. RG 223 is the thin double-screened variant for test setups and cabinet wiring.

Choosing by attenuation and screening

Determine the working frequency and the cable length, and read the attenuation per 100 metres at that frequency in the datasheet. Then choose the screening to suit the environment: single braid where interference is low, double where power cables or transmitters are nearby. The RG number is the outcome of that choice, not the starting point.

Fixed installation and CPR

For fixed installation in buildings the Construction Products Regulation applies to coax too, so the cable carries a CPR class. Our coaxial types are Eca as standard; the TY-ZH and U-ZH versions are also halogen-free. Where the cable is installed permanently in a building and exposed to indoor air, the Bbl requires at least Dca. For that, we supply RG6 and RG59 on request in a halogen-free version in Dca or B2ca. Loose patch cables in a rack are not covered by that requirement.