Assembling an RF Coaxial Cable Assembly

Low Loss Coaxial RF Cable Assembly with Type-N Connectors

RF coaxial cable assemblies are a ubiquitous form of RF interconnect found in virtually all RF and some analog and high-speed digital systems. The benefits of RF coaxial cabling over other cabling are well known but are only achievable with proper coaxial cable assembly. This blog outlines the general steps and tools needed to assemble RF coaxial cable and why this may be desirable.

Why make custom length or type RF coaxial cable assemblies?

In many situations the exact length of cable needed to connect two ports may be unknown until after assembly. In some cases of high volume manufacture, it may be cost effective to buy cable and coaxial connectors separately and have cable assembled on hand. It may also be quicker to have coaxial cable and coaxial connectors on hand to assemble whatever cable is needed as a situation arises, as opposed to having to custom order a cable assembly. Additionally, a cable with different type end connectors may be needed, which can be readily assembled in-house and may not be available immediately otherwise.

These potentialities are much more common when working with older systems and while performing maintenance on systems that are already installed. However, oftentimes even new installations or systems might require some custom coaxial cable assembly on-site, as there may be errors in the installation or system drawing, or a customer may require a custom configuration that requires some rerouting.

How to correctly assemble RF coaxial cable assemblies

When making a coaxial cable assembly it is first important to ensure that the coaxial cable and connector type are compatible. There are some rf coaxial cables and some rf coaxial connectors that are able to be connected and some that are not the correct size or tolerance to be compatible. There are also RF cables that are similar to coaxial cables but have a different style of internal conductors and dielectrics, such as twinax cables.

Assembly Steps

1 Ensure appropriate coaxial cable and connectors are selected
2 Ensure all of the coaxial connector components are available
3 Cut the coaxial cable to the desired length
4 Place the heat shrink, metal collar, gasket, and/or nut on the coaxial cable if needed.
5 Appropriately dress the coaxial cable per specifications for the cable and coaxial connector. This involves removing the outer jacket and inner dielectric down to an appropriate length and moving the outer shielding/armor layers away from the center conductor.
6 Crimp, solder, press-fit, press-through, or otherwise prep and assemble the coaxial cable center conductor and coaxial connector center pin
7 Crimp, solder, wrap, or otherwise prep and assemble the coaxial cable shielding (outer conductor) and coaxial connector outer housing. This may involve placing a collar or crimp ring around the coaxial cable or connector after fitting the connector body to the coaxial cable.
8 Tighten, press fit, or otherwise ensure correct coaxial connector housing insertion on the coaxial cable with whatever appropriate sealing gaskets or material.
9 Attach or otherwise assemble the heat shrink or other mechanical strain relief the coaxial connector may come with