Imperial Beach/Chula Vista

i was in imperial beach or chula vista (kinda on the border) today and i noticed that there was a big ass area that was fenced off in a huge circle... the fence looked about 50 feet tall and the circle looked really really huge...if anyone knows what im talking about or knows what it is could they please tell me. cause i wanna know what the fuck this shit is

thanks.

I posted your answer in the other forum.. it is in IB and is a communications station ( fcc/military)