According to the application location of the coaxial line, it can be roughly divided into 3 types.
1. Trunk cable: Thick cable with an insulation outer diameter of generally 9mm or more, which requires low loss and low flexibility.
2. Branch line cables: medium and thick cables with an insulation outer diameter of generally 7mm or more, which require small losses and also have a certain degree of flexibility.
3, user distribution network cable: its insulation outer diameter is generally 5mm, loss requirements are not major, but require good flexibility and indoor uniform straight coordination.
In specific applications, if the wiring length is too long and the signal attenuation is serious, it is a good idea to choose a thicker coaxial line.
I always hear people say the line of -7, -5, do you know what it means? This also starts from the name of the coaxial cable. In order to make it easier for everyone to see the structure type of the coaxial cable model, the unified method of coding and the meaning of the code of the cable in China are given below for your reference. The name of a coaxial cable usually consists of 4 parts.
The first number behind the national standard is the characteristic impedance. The characteristic impedance is determined by the structure and has nothing to do with the conductor resistance. It can be understood as the impedance of the cable at infinite length. Commonly used are 75Ω, 50Ω, and 93Ω.
The second number is the inner diameter of the outer metal. The larger the number, the thicker it is. In order to ensure a stable characteristic impedance, the inner conductor will also become thicker accordingly.
The third number is the serial number. The difference between each serial number depends on the manufacturer's instructions. There is no uniform rule.
The above is the naming method of the national standard coaxial line. The coaxial was first used by the United States in the military. The RG-59 (75Ω), RG-58 (50Ω), and RG-213 (50Ω) in the US military standard are commonly used by us. of.