Radio frequency cable assemblies consist of a coaxial cable with the most appropriate connectors attached to the ends for interconnecting devices known as signal transmitters and receivers. The most common types of cables used for this purpose are known as flexible, semi-rigid, and rigid, with a few exceptions and hybrids. If you are considering purchasing customized cable for your next electrical project, consider this your guide to understanding these three types of cable assemblies.
The first thing to know about cable assemblies is how are they composed. An inner conductor material, usually some form of copper, is selected by the engineer or designer. This is what actually transmits the signal. Surrounding this is tubular insulating material and shield that prevent the wire from generating excess heat, and prevents the cable from being penetrated by moisture. The cable is then wrapped in a shielding material to prevent signal loss, noise, and interference from other signals. Finally, an outer jacketing material is placed on the cable to make it water-resistant.
One of the most common types of coaxial cable is the flexible cable typically used by cable television technicians to connect video equipment within your home. The cable consists of a metal conductor, polymer insulation, braded shield and finally a jacket to prevent it from environmental factors. What makes this wire flexible is the materials used. For more flexibility engineers will use a stranded conductor, polyethylene foam insulator, and braided shielding that has give in every direction.
Although this type of cable is more flexible, the trade-off is that the braded shield can cause variations in the electrical performance of the cable to transmit a signal with fidelity. Bends and kinking in the cable can lead to unwanted noise and interference.
To obtain better performance, many designers are willing to sacrifice flexibility by using a semi-rigid design. These place a higher emphasis on electrical properties, and slightly less on shielding quality. The primary difference between semi-rigid and flexible cable is that semi-rigid cable typically has a metal outer jacket that is bendable, however once it is bent into the desired shape, it typically stays in that configuration.
Finally, we come to rigid cable. This type of cable is composed of two copper tubes supported at the ends and at regular intervals with supports. Additionally, this type of wire cannot be bent, but must have specially constructed “elbow joints” of 45 and 90 degrees in order to accommodate any turns, angles, or obstacles in the layout of the design. This type of cable is primarily used indoors, specifically for components that require high amounts of power, such as TV and FM broadcasting stations.
For more information on how to customize your cable assemblies for your next project, contact us at LoDan Electronics today!