The CCIR considering: a) that severe degradation of television reception can be caused by reflections from moving objects such as the blades of a wind turbine; b) that these effects are particularly serious because the impairment caused can be quasi-permanent, being reduced only during periods when the wind turbine is not rotating; c) that it is important to have available a simple method for calculating the potential impairments which could be caused by the installation of any proposed wind turbine; d) that ghost cancellation techniques are being investigated and that these may offer some amelioration of the impairment caused by wind turbines.