. Moreover, the fact that an adversary target knows a priori its relative location means that even with pure noise transmission the radar is vulnerable to false echo creation by a delaying repeater on the target. Nonetheless, SS signaling has some advantages over conventional low time-bandwidth-product radar signaling: in better range (TOA) resolution for a peak-power-limited transmitter (via pulse compression techniques), in range ambiguity removal, in greater resistance to some nonrepeater jammers [7], and in a CDMA-like capability for sharing the transmission band with similar systems. Modern uses of SS radars include fusing (for a patent under wraps for twenty-four years, see [191]) and pulse compression, the latter's applications extending to high-resolution synthetic-aperture ground map- ping. 2.3.2 Other Early Spread-Spectrum Communication Systems Despite the security which once surrounded all of the advances described in previous sections, the SS system concept could not be limited indefinitely to a few companies and research institutions. The following notes describe several other early SS design efforts. Phantom: An MF-SS system developed by General Electric (GE) for the Air Force, this system was built around tapped delay line filters. As shown in Costas and Widmann's patent [192], the tap weights were designed to be varied pseudorandomly for the purpose of defeating repeater jammers (see Figure 2.29). Constructed in the late 1950s, the Phantom spread its signal over 100 kHz. As with the F9C-A, this system was eventually used also to mea- sure long-haul HF channel properties. For a description of other SS-related work performed at GE in the 1951-54 time frame, under the direction of Richard Shuey, see [193]. WOOF: This Sylvania Buffalo system hid an SS signal by placing within its transmission bandwidth a high-power, friendly, and overt transmitter. Thereby, the SS transmission would be masked by the friendly transmitter, either completely escaping notice or at least compounding the difficulties encoun