At 432 metres elevation I'm surprised that nobody has ever run into the Omega tower in Gippsland, Victoria, based on the comments in the article above.
It had been there for 32 years and has just been demolished. It was harder to see than a wind farm turbine is exponentially, plus it had guide wires that gave it a significantly large footprint, as much as several wind turbines and it was even adjacent an RAAF low flying area.