heavy bomber, exclud- ing Pathfinders, on the German front was equipped with at least two jammers developed by the Radio Research Laboratory (RRL) at Harvard [11]. The use of chaff was prevalent, the Allies consuming 2000 tons per month near the end. On the German side, it is estimated that at one time, as many as 90 percent of all available electronic engineers were involved in some way in a tremendous, but unsuccessful, AJ program. Undoubtedly Kugelschale and Reisslaus were products of this effort. In a postwar RRL report [11], the following comment on AJ design is notable: In the end, it can be stated that the best anti-jamming is simply good engineering design and the spreading of the operating frequencies. Certainly, spectrum spreading for jamming avoidance (AJ) and resolution, be it for location accuracy or signal discrimination (AJ), was a concept famil- iar to radar engineers by the end of the war. In the late 1950s and early 1960s, the East German scientist H. Lange toured Europe and the United States collecting (unclassified) material for a book on correlation techniques. Published first in 1959 with its third edition being translated into English [12] a few years later, Lange's book contains some references all but unnoticed by researchers on this side of the Atlantic. The most intriguing of these is to the work of Gustav Guanella (Figure 2.1) of Brown, Boveri, and Company in Switzerland. Among Guanella's approx- imately 100 patents is one [13] filed in 1938, containing all the technical char- acteristics of an SR-SS radar! The radiated signal in Guanella's CW radar is "composed of a multiplicity of different frequencies the energies of which are small compared with the total energy" of the signal. His prime examples of such signals are acoustic and electrical noise, and an oscillator whose fre- quency is "wobbled at a high rate between a lower and upper limit." Ranging is accomplished by adjusting an internal signal delay mechanism to match the external propagation delay experienced by the transmitted