An abandoned United States Air Force General Surveillance Radar station. There's a little bit here (some ground pictures): http://www.abandonedbutnotforgotten.com/abandoned_millitary_base_-_brookfield,_oh.htm
http://illicitohio.illicitohio.com/brookfield.html
http://radomes.org/cgi-bin/museum/acwinfo2x.cgi?site=%22Brookfield%2BAFS,%2BOH%22&key=BrookfieldAFSOH&doc=BrookfieldAFSOH