Monday, November 19, 2012

Coaxial cable

            Today the coaxial cable is a transmission medium most widely used on the Local Area Network and a choice of many people because in addition to low cost, this type of cable is also easy to use.

Physical Description

            Coaxial consists of two conductors, set up to operate on a large frequency band. Consists of the core conductor and surrounded by small wires. Among the core conductors with conductors separated by an insulator surrounding (jacket / shield). Coaxial cables are less likely to interfere due to the shield. Coaxial can be used to remotely support more terminal preformance a common pathway.

            Coaxial cable users in general are:
·         Antenna Television
·         Transmission distance phone
·         Link the computer
·         LAN

Type Coaxial Cable
Coaxial cable is divided into 2 parts baseband coaxial cable (50 ohm cable) used for digital transmission and broadband coaxial cable (75 ohm cable) used for analog transmission.
·         Baseband Coaxial Cable
            This type of coaxial cable consists of copper wire as the hard core, surrounded by an insulating material. Isolator is wrapped by a cylindrical conductor, which often takes the form of woven fabric. Outer conductor enclosed in a protective plastic sheath.

            Construction and protective coating coaxial cables provide a good combination of large bandwidth and noise immunity privilege. Bandwidth depends on the length of the cable. For a cable length of 1 km, the data rate can reach 1 to 2 Gbps. Longer cable could also be used, but will only reach a lower data rate. Coaxial cable is widely used in telephone systems, but at this time for longer distances used type of fiber optic cable.

·         Broadband Coaxial Cable
            Other coaxial systems using analog transmission systems on cable television wiring standard. Such a system is called broadband. Because broadband networks require cable television technology standards, cables used up to 300 MHz and can operate almost 100 km with respect to analog signaling, which is more secure than digital signaling.

            To mantransmisikan digital signals on analog networks, the interface must be installed on every electronic device to turn off the bit stream into an analog signal and the incoming analog signal into a stream of bits.
An important difference between the baseband with broadband is that the broadband system covering a wide area compared to the baseband system.

Type Coaxial Cable
Coaxial cable is divided into 2 types of tin (thinnet) and thick (thicknet). The difference is the thin cable is more flexible, easier to use and more importantly cheaper than thick wires. Thick cable is thicker and more difficult to bend and reach further than the thin, which makes it more expensive. For comparison the thin cable range is 185 meters while the thick cables reaching up to 500 meters. Both types of these cables use the same components known as the BNC (British Naval Connector) to connect the cable to the computer. Components of this include the BNC connector BNC cable, BNC T connector, BNC connector and a BNC terminator barrel.

Transmission characteristics
Coaxial can be used for analog signals and digital signals. Because it is formed by using a shield then less likely to interfere, and the cross talk. For transmission of analog signals, each several kilometers should be given amplifier. The spectrum used for signaling is around 400 Mhz. Likewise for digital signals, repeaters are needed in every kilometer.

Advantages and Disadvantages
Cable noise is virtually unaffected and relatively inexpensive. However, the use of these cables easily hijacked. In addition, the type of thick coaxial is not allowed to be installed in some kind of space.

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