50Ohm Coaxial Cable And 75Ohm Coaxial Cable Usage

What are the uses of 50Ohm coaxial cable and 75Ohm coaxial cable？

The word "coaxial" comes from wire construction. The skin effect produced by the same charge repulsion is used to cover the positive electrode with a shield, which can reduce the interference of the environment on the signal. In this way, the shielding layer and core wire form concentric circles, so called coaxial.

Why 75ohm and 50ohm, and not 100, 1,000 or whatever? These two values were chosen to consider both "minimum loss" and "maximum breakdown power".

For air media, the "minimum loss" is preferred, and the optimal ratio of the inner diameter of the shield layer to the outer diameter of the core wire is required to be 3.6 (the derivation process is complicated and omitted). In this case, the characteristic impedance of the cable is 77Ω . Under this ratio, although the cable loss is small, the shield layer and core layer will break down in case of high power. Similarly, when the maximum power capacity is considered, the ratio of the inner diameter of the shield layer to the outer diameter of the core wire is 1.65, and the corresponding characteristic impedance is 30Ω. In this case, the cable loss is high.

Therefore, in the case of weak signals with low transmission power (such as TV signals), 75 ohms is adopted as the minimum loss point below 77 ohms for simple calculation. 50 is the average approximation of 77 and 30, a compromise between minimum loss and maximum power capacity. That is, 50 ohms has more carrying power than 70 ohms.

What is the difference between 50 and 75 ohm cable?

The 75 ohm coaxial cable is generally used as the connecting wire for video signal transmission.
50 ohm coaxial cable is generally used for monitoring signals, wireless signal transmission with the connection wire.

50 ohm for radio, 75 ohm for TV, both transmit signals, 75 ohm better than 50 ohm transmission signal, picture and sound quality is clear. 50 ohm is enough for the radio to carry sound.

Learn more at :  https://www.ctccables.com/Coaxial-Cable