Wind turbines may be a source of disturbance in the radiation fields of TV broadcast transmitters. The situation is particularly serious when the direct path from the transmitter to the receiver antenna is obstructed while both transmitter and receiver antennas have a unblocked path to the wind turbine. Starting from an analysis of the diffracted field by the pylon we proceed to implement a simple rule derived from ITU Recommendation 805 to define a minimum clearance distance from an isolated wind tur- bine and a TV transmitter antenna. Measurements using a scaled model confirm the existence of the floor level in the scatter model used in ITU Recommendation BT.805.
The paper deals exclusively with impairment of analogue signals. ITU-Rec BT.805 is discussed in Report ITU-R BT.2142-1 (10/2010), where a draft replacement recommendation is described.
NB The publishing source of this paper has not been identified.