5) Describe how much attenuation is experienced for different frequencies for a. Twisted pair cable b. Coaxial cable C. Optical fiber 6) What is the main characteristics of an isotropic antenna? Explain shortly. Then describe the major characteristics of a parabolic antenna. Describe how an electromagnetic wave travels in ground wave propagation mode, sky wave propagation mode, and line of sight propagation mode. 8) When does refraction happen? Explain it shortly 9) Consider an antenna with the height of 100 meters. a. What is the optical line of sight distance? b. What is the radio line of sight distance