At present, there are two kinds of RF coaxial cable commonly used: 50 Omega; and 75;
Characteristic impedance 75; RF coaxial cable is commonly used in CATV network, so called CATV cable, transmission bandwidth of up to 1GHz, currently commonly used CATV cable transmission bandwidth: 750MHz.
Characteristic impedance 50 Omega; RF coaxial cable is mainly used for baseband signal transmission, transmission bandwidth is 1 2omhz,
The general characteristic impedance 50 Omega, the maximum transmission distance of the fine coaxial cable is 180 meters, and the coarse coaxial cable can reach 1000 meters.
The name of the RF coaxial cable is related to its structure. RF coaxial cable is also one of the most common transmission media in LAN. A pair of conductors used to transmit information are sheathed in a cylindrical outer conductor outside the inner conductor (a thin core) the two conductors are separated from each other by the structure of insulation material, the outer conductor and center axis Core line are in the same axis, so called RF coaxial cable, RF coaxial cable is designed to prevent the external electromagnetic wave interference abnormal signal transmission.
The RF coaxial cable according to its diameter can be divided into: coarse RF coaxial cable and fine RF coaxial cable. The coarse cable is suitable for the large local network, its standard distance is long, the reliability is high, because the installation does not need to cut off the cable, therefore may flexibly adjust the computer's network position according to the need, but the thick cable network must install the transceiver cable, the installation difficulty is big, therefore the overall cost is In contrast, the installation of fine cables is relatively simple, low cost, but because the installation process to cut off the cable, both ends must be fitted with the basic network connection Head (BNC), and then connected to the T-type connector at both ends, so when the joint is prone to bad hidden trouble, this is the current operation of the Ethernet is one of the most common failure.
This is RF coaxial cable. Whether it is a rough or fine cable is a bus topology, that is, a cable connected to multiple machines, this topology is suitable for a machine-intensive environment, but when a contact failure, the failure will cascade affect all the machines on the entire root cable. Fault diagnosis and repair are cumbersome, so it will gradually be replaced by unshielded twisted pair or cable. But the RF coaxial cable still has its market space.