System for testing performance of leaky cable in simulation tunnel

Abstract

The invention discloses a system for testing performance of leaky cable in simulation tunnel. The tunnel simulating environment adopted by the testing system comprises a test rail, a test trolley, test instrument, an antenna and a special fixture for leaky cables, wherein the test rail is positioned in the centre of the tunnel; the test trolley runs on the rail; the test instrument and the antenna are mounted on the test trolley; and the special fixture for leaky cables is arranged on the tunnel wall. In the system for testing performance of leaky cable in simulation tunnel, the test environment is the simulated real mounting environment of the leaky cable, the test result of the system better approaches to the actual demands, more accurate data can be provided for a user in system design, and reasonable selection and application of the leaky cable are convenient for the user.

Description

technical field [0001] The invention relates to a leaky cable performance test system for simulating a tunnel. It belongs to the communication cable industry and is used to simulate and test the performance of leaky cables when they are used in various forms of tunnels. Background technique [0002] Leaky coaxial cable is a kind of coaxial cable that has both transmission characteristics of transmission line and antenna radiation characteristics. It is suitable for environments such as subways, tunnels, and special areas with narrow and long internal structures. The performance test of the leaky cable is generally carried out by each manufacturer in accordance with the IEC61196-4 standard, which stipulates that within the scope of a cylinder with a diameter of at least 2m around the geometric center of the leaky cable axis and the center point of the antenna, no other than cables and cables are allowed. Other metals or conductors other than the antenna belong to the free sp...

AI Technical Summary

Problems solved by technology

The performance test of the leaky cable is generally carried out by each manufacturer in accordance with the IEC61196-4 standard, which stipulates that within the scope of a cylinder with a diameter of at least 2m around the geometric center of the leaky cable axis and the center point of the antenna, no other than cables and cables are allowed. Other metals or conductors other than the antenna belong to the free space test standard, which can only test the radiation performance of the leaky cable itself, and cannot know the radiation performance of the leaky cable in the actual installation environment

[0003] In addition, various leaky coaxial cable standards include all performance requirements of coaxial cables, such as impedance, attenuation, standing wave, frequency of use, etc., while only standard coupling loss is listed in terms of radiated electric field characteristics (here it can be called is the length coupling loss), while in the omnidirectional antenna standard, the performance requirements listed include gain, pattern circularity, half power width, etc.; and due to cable laying, geographical environment and other reasons, moving objects and antennas are impossible Always maintain the condition of the length coupling loss test that is vertical and equidistant from the slot hole of the leaky coaxial cable, so a single length coupling loss test item cannot fully reflect the characteristics of the radiated electric field of the leaky coaxial cable

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