1) Describe fully the operation of a yagi-uda array and state its advantages. Also explain why this antenna is referred to as the super-gain antenna?
2) A VHF communication is to be established having 35W transmitter at 90MHz. Calculate the distance upto which the line of sight communication may be possible if height of the transmitting and receiving antennas are 40m and 25m respectively. Also, find the field strength at the receiving end.
3) Determine the transmission path distance for an ionospheric transmission which utilizes the layer of height 200Km. The angle of elevation of antenna beam is 20 degrees. The earth’s radius can be supposed to be 6370Km.
4) How the field pattern of the receiving antenna experimentally is found? Provide the block diagram description and describe. Is reciprocity principle used in this?
5) Explain an experimental set-up to determine the effective height of the ionosphere and critical frequency.