Klein Heidelberg—The First Modern Bistatic Radar System

We present a description and analysis of the German WW2 bistatic radar system Klein Heidelberg (KH). A brief account is given of the nature of the electronic war between the Allied bombers and the German air defense system, to show the context in which the KH system evolved. This is followed by a description of the development of KH, a technical description, and an assessment of its performance. Next, a discussion of its operational significance, of what happened after WW2, and finally some conclusions and some lessons learned that may be relevant to the development of present-day bistatic radar systems. In particular, we show that its performance was impressive, yielding detection ranges of Allied bombers in excess of 300 km, but that it became operational too late in WW2 to significantly improve German air defense operations.