What is this strange structure, of a type often seen by pilots in hilly regions? I spotted a strange structure near a few paragliding spots in italian Alps. It's a screen about 10 meters wide, 6 meters tall, mounted on concrete base on ridge top. Someone said it's a training target for fighter jets, is it true? If so, is it targeted with real ammo or some kind of video-based training system?

Pictured: Monte Dolada, 46°11'34.68"N, 12°20'25.41"E
It's a reflector for microwave links, a passive repeater.

More info here (article in Spanish): http://notascordobesas.blogspot.com/2015/01/el-repetidor-pasivo-de-microondas.html