What are the parameter indicators of coaxial cables?
Main electrical parameters.
(1) The characteristic impedance of coaxial cable is 50 ± 2 Ω, and the impedance of a single coaxial cable varies periodically as a sine wave, with a center average value of ± 3 Ω and a length of less than 2m.
(2) The attenuation of coaxial cable generally refers to the attenuation value of a 500 meter long cable section. When measured with a 10mHz sine wave, its value does not exceed 8.5db (17db/kilometer); When measured with a 5mHz sine wave, its value does not exceed 6.0db (12db/kilometer).
(3) The lower transmission speed required for coaxial cable transmission is 0.77C (C is the speed of light).
(4) The sum of the center conductor resistance and shielding layer resistance of coaxial cable DC circuit resistance cable shall not exceed 10m ohms/m (measured at 20 ℃).
Physical parameters:
Coaxial cables consist of a central conductor Insulation material layer Composed of mesh fabric and outer isolation material layer. Coaxial cables have sufficient flexibility to support a bending radius of 254mm (10 inches). The central conductor is a solid copper wire with a diameter of 2.17mm ± 0.013mm. The insulation material must meet the electrical parameters of coaxial cables. The shielding layer is composed of metal strips or sheets that comply with transmission impedance and ECM specifications. The inner diameter of the shielding layer is 6.15mm and the outer diameter is 8.28mm. Polyvinyl chloride (such as polyvinyl chloride) or similar materials are commonly used as external isolation materials.
Main parameters:
(1) An open circuit in a conductor or shielding layer.
(2) Short circuit between conductor and shielding layer.
(3) Conductor grounding.
(4) Short circuits between shielding joints.
