Cable television is a technique of transmitting images and sound simultaneously to many television sets through cables instead of through high frequency radio waves. Being high frequency waves, television signals transmitted by telecasting stations can be received properly only if the receiving antenna is in direct line of sight of the transmitter. At far off places the signals received are weak. Besides, the transmitted TV signals are blocked by hills or high-rise buildings. Cable TV can help in such situations. It enables many TV sets to simultaneously receive signals with the help of a single antenna located at a suitable place. Signals from the antenna are amplified and distributed to TV sets through a network of cables. Signals transmitted by satellites can also be received by large dish-antenna and distributed through cables.
Clear signals are received by the TV sets because the transmission is through insulated cables. The cables are special co-axial cables in which a central core conductor is surrounded by another conductor —a mesh. Thus even if the cables are bent or twisted; the signals carried by one conductor do not hamper the transmission of signals by the other. Besides, amplifiers are also used to strengthen the signals so that each TV set gets sufficiently strong signals to produce a clear image.