How to choose the coaxial cable?

1. Impedance: The impedance of the coaxial line is mainly 75 ohms and 50 ohms. The type of device and device that needs to be connected determines the cable impedance that needs to be used.

2, attenuation: signal energy can be lost due to conductor resistance caused by thermal energy, dielectric loss factor and other factors related to the quality of coaxial cable materials. The thinner and longer the cable, the greater the attenuation. Therefore, the appropriate coaxial line needs to be selected according to the desired signal transmission distance and the acceptable degree of signal attenuation.

3. Frequency characteristics: the attenuation of coaxial cable is proportional to the square root of frequency. Coaxial cable with good frequency characteristics has a smooth characteristic curve in the whole frequency band range. Therefore, it is necessary to select the appropriate coaxial line according to the desired operating frequency range.

4, echo (reflection) loss: the ratio of incident power to reflected power, dB value. Under normal circumstances, the higher the operating frequency, the smaller the reflection loss. From the point of view of signal transmission quality, the greater the reflection loss, the better, which indicates that the internal structure of the cable is more uniform. The less likely it is to form reflected waves, the less likely it is to form standing waves.