I worked at the site from 1978 to 1981 and at other sites until 2001. The NASA Tracking Station Dandan was closed in the early 1990s after the Tracking Data Relay Sattilite System (TDRSS) came fully on line.
In the late 1990's NASA built a remote TDRS ground terminal near Dededo to support new capability over the Indian Ocean
http://www.panoramio.com/photo/50194916