Fig 4. Your antenna on a flat roof; never route the antenna mast through the roof, also not here!

In the sense of this brochure it is recommended to take measures at antenna masts higher than two meters above free standing houses in open build areas and also to antennas, which are more than five meters above close build areas.

But lightning sometimes also hits in lower antennas.

With open build areas we mean an area, where houses are free standing (bungalow- parks etc).