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10 LAW ENFORCEMENT TECHNOLOGY AUGUST 2017 www.officer.com T R A ININ G A N D O F F I C E R S A F E T Y Circle 5 on Reader Service Card the jammer. Most high-end jammers do not suffer from either of these problems. In cases where the jammer- operator does not shut the system off, the LIDAR may never receive a speed, no matter how close the target vehicle is. Speed and jammer-enthusiasts call this "jam-to-gun." If you are unable to receive a speed reading from a vehicle at extremely close distances this is a sign that you may have been jammed. Some jammers claim to be "park- ing sensors" and may have documen- tation to that effect. They may indeed work as a limited range parking sensor; however, their primary func- tion is to jam police LIDAR . Check the Internet for that particular jam- mer make and model to quickly reveal its true purpose. Mitigating jammer effectiveness The single best way to reduce the pos- sibility of getting jammed is to ensure that you operate LIDAR at distances less than 500 feet. Remember that at 1,000 feet most LIDARs produce a 3-foot wide beam pattern. This increases the amount of refracted LASER energy that can get to the jammer sensors. It also increases the amount of surface area on the target that can reflect and refract that LASER energy, thus increasing detectability. Additionally, at distances beyond 500 feet the jammer becomes increasingly effective because its signal is much stronger than the LIDAR's. Because most front jammers are mounted on the license plate or near the headlights, aiming for other areas can help reduce the chance of getting jammed. Roofline, mirrors, and engine hoods can be used at close distances when shooting from the front. Since the vast majority of jammer installations are front only, shooting target vehicles from the rear provides a greater chance of obtaining a jam-free reading. Jammers are designed to be effective as long as the LASER beam from the LIDAR and the jammer are on the same plane. Shooting LIDAR from an ele- vated position such as a hill, overpass, or exit/on-ramp also makes jamming more difficult. My testing has found that another limitation of jammers is they are only able to jam one LIDAR at a time. The jammer will alternate back and forth between multiple LIDAR signals allow- ing them both to get readings at alter- nating times while the other is jammed. While somewhat impractical, officers who are running LIDAR together may be able to overcome jammers by having each officer shoot the same car.