Michael "Mike" Grube's extensive SIGINT web site HERE
Click below for links on his web site which may be of particular interest:
The British Listening Post at Elm
Meissner and the German Army Towers
Wurmberg - La Fair Vite North
Diesdorf - A Soviet Listening Post
Brocken - Soviet/GDR Listening Post
Berlin - A summary about SIGINT in Berlin
Stoeberhai - About those German "missile towers"!
Under the heading "Funk- und Fernmeldeaufklärung" on the pagehttp://www.lostplaces.de/inhalt-thema.html there are links to 12 pages of info and photos of Bundewehr, US, French, Russian and East German spy sites/towers.
German web site www.gssr.de (which is an interesting place to visit) and directly at http://www.gssr.de/MYSTISCHES/schoeningen.htm