If the collecting area is in pieces, the effective diameter (the distance between the two most widely spaced pieces) can be several thousand kilometres.

ECONOMIST: Radio telescopes

Because the output of a wind turbine also tends to increase proportionally with its distance from barriers such as trees or buildings, the most productive -- and cost-effective -- turbines sit atop tall towers erected on an acre or more of open land.

CNN: Stimulus may get small wind turbines spinning