Copper Wire and Its Limitations

Due to the electrical properties of copper wiring, data signals will undergo some corruption during their travels. Signal corruption within certain limits is acceptable, but if the electrical properties of the cable will cause serious distortion of the signal, that cable must be replaced or repaired.

As a signal propagates down a length of cable, it loses some of its energy. So, a signal that starts out with a certain input voltage, will arrive at the load with a reduced voltage level. The amount of signal loss is known as attenuation, which is measured in decibels, or dB. If the voltage drops too much, the signal may no longer be useful.

Attenuation has a direct relationship with frequency and cable length. The high frequency used by the network, the greater the attenuation. Also, the longer the cable, the more energy a signal loses by the time it reaches the load.

A signal losses energy during its travel because of electrical properties at work in the cable. For example, every conductor offers some dc resistance to a current ( sometimes called copper losses). The longer the cable, the more resistance it offers.

Resistance reduces the amount of signal passing through the wires -- it does not alter the signal. Reactance, inductive or capacitive, distorts the signal.

The two primary concerns of signal transmission are:

  1. That enough signal gets through. (Quantity)
  2. That the signal is not distorted. (Quality)