Janson unzipped his knapsack and removed the police radar detector. It was a Phantom II, a high-end model meant for motorists who liked to speed and didn’t like speeding tickets. What made it so effective was that it was both a detector and a jammer, aiming to make a motorist’s car “invisible” to speed-detecting equipment. It worked by detecting the signal and bouncing it back toward the radar gun. Janson had removed its plastic casing, shortened the nub of its antenna, and installed an additional capacitor, thus shifting its radio-frequency spectrum to the microwave bandwidth. Now he used duct tape to fasten the device near the end of the long telescoping steel rod. If it worked as he hoped, he would be able to exploit an inherent design feature of all outdoor security systems: the necessary tolerance for wildlife and weather. A security system was useless if it regularly issued false alarms. Outdoor microwave systems always used signal processing to distinguish human intruders from the thousand other things that could cause anomalies in the signal—a branch tumbling in the wind, a scampering animal.

Still, he was taking a stomach-plunging gamble. In less exigent circumstances, he would have field-tested his hypothesis before staking his life on it.

One more time, he studied the configuration of the stanchions. The bistatic sensors could be placed as far as seven hundred feet away from each other. These were merely a hundred feet away—a spare-no-expenses approach that must have gladdened whoever had been paid to install the system. And yet the proximity of the sensors was another factor in Janson’s favor. The farther apart they were, the broader the coverage pattern between them. At 250 yards, the coverage pattern would swell to an oval that reached, at the midpoint between the two sensors, a width of forty feet. At thirty yards, the coverage pattern would be tighter and more narrowly focused, no wider than seven feet. That was one of the things that Janson was counting on.