PART 1 : ADVANTAGES AND DISADVANTAGES OF COAXIAL CABLE??

Coaxial cable is still the most common means of data transmission over short distances. The advantages are: - they are cheap to make - cheap to install - easy to modify - good bandwith - great channel capacity - noise immunity due to low error rate
The advantages of using coax include the following:Broadband system Coax has a sufficient frequency range to support multiple channels, which allows for much greater throughput. Greater channel capacity Each of the multiple channels offers substantial capacity. The capacity depends on where you are in the world. In the North American system, each channel in the cable TV system is 6MHz wide, according to the National Television Systems Committee (NTSC) standard. In Europe, with the Phase Alternate Line (PAL) standard, the channels are 8MHz wide. Within one of these channels, you can provision high-speed Internet access-that's how cable modems operate. But that one channel is now being shared by everyone using that coax from that neighborhood node, which can range from 200 to 2,000 homes. Greater bandwidth Compared to twisted-pair, coax provides greater bandwidth system wide, and it also offers greater bandwidth for each channel. Because it has greater bandwidth per channel, it supports a mixed range of services. Voice, data, and even video and multimedia can benefit from the enhanced capacity. Lower error rates Because the inner conductor is in a Faraday shield, noise immunity is improved, and coax has lower error rates and therefore slightly better performance than twisted-pair. The error rate is generally 10-9 (i.e., 1 in 1 billion) bps. Greater spacing between amplifiers Coax's cable shielding reduces noise and cross talk, which means amplifiers can be spaced farther apart than with twisted-pair.
 The main disadvantages of using coax are as follows:Problems with the deployment architecture The bus topology in which coax is deployed is susceptible to congestion, noise, and security risks. Bidirectional upgrade required In countries that have a history of cable TV, the cable systems were designed for broadcasting, not for interactive communications. Before they can offer to the subscriber any form of two-way services, those networks have to be upgraded to bidirectional systems. Great noise The return path has some noise problems, and the end equipment requires added intelligence to take care of error control. High installation costs Installation costs in the local environment are high. Susceptible to damage from lightning strikes Coax may be damaged by lightning strikes. People who live in an area with a lot of lightning strikes must be wary because if that lightning is conducted by a coax, it could very well fry the equipment at the end of it.