(a)[2]
State two roles of the copper braid.
(b)[2]
Suggest two reasons why a coaxial cable is preferred, rather than a wire pair, for connecting the aerial to the receiver.
(c)[3]
A coaxial cable has an attenuation per unit length of $200\,\text{dB km}^{-1}$. The coaxial cable between an aerial and the receiver is $12\,\text{m}$ long. Calculate the ratio $\frac{\text{input signal power to coaxial cable}}{\text{output signal power from coaxial cable}}$.