Why is it there and what is it?

Went for a walk along the ridgeline of Tinakori Hill today. Magnificent views, and very enjoyable on a hot sunny day like today.

Everytime go up there and I look at the above structure and wonder what the hell was it meant to be, and why is it up there. Sometimes I think it looks like a basketball scoreboard. At other times I think it is the back of a hoarding. Others, maybe it could be a screen for a drive-in movie.

However it is on of a hill with no vehicle access and stuff all passer-bys. Why would you have it there?

Someone out there I reckon knows what it is, and the history of it. If you do, please leave a comment.

Oh yes, and could the owner please clean the graffiti off it.

UPDATE: Thanks to some smart readers, the mystery has been solved. It is a passive microwave repeater. I would have never guessed that due to the lack of electronics or electricity to it, but of course it doesn't need any.