Impact of Wind Turbines on TV Reception
February 2, 2004
National Transmitters Ltd Broadcast (NTL), the landlord of the Tealing TV transmitter facility near Dundee, England, expressed concern that the 340-foot wind turbines Michelin is planning to install in Dundee could interfere with TV reception in the Broughty Ferry area. The wind turbines may lie in between the Tealing tower and the area. An article - Turbines could hit TV reception - in the Evening Telegraph quoted an NTL Broadcast spokesman saying, "Wind turbines are becoming more and more of an issue because if you have large, metal structures which are moving, then pictures can be severely distorted."
The spokesman said that while digital signals were less affected than analog signals, there could be "serious effects" if the wind turbines were the path from the transmitter site to the viewer. See the article for information on how the city council is dealing with this.
You may recall that plan for the Freedom Tower in New York City has the TV transmitting antennas located above wind turbines. See the December 22 RF Report. In an email in response to that report, Charlie Rhodes pointed out the rotating metal blades in the turbine could reflect RF from the transmitting antennas above. The phase of any of the TV signals reflected from the turbine blades would vary as the blades rotated, making adaptive equalizers work hard to compensate for the varying reflections. Although I could see how downward radiation from the transmitting antennas on the Freedom Tower above the turbines could be greatly attenuated to reduce the varying reflection problem, it seems the turbine could have an influence on DTV reception in some areas from transmitters at other sites.
As alternative energy systems such as wind turbines become more widespread, TV interference from wind turbines could become an issue here. Have any readers seen cases of TV interference from wind turbines or windmills?