Theoretically, the Passive Scrambler would function well if the antenna of the Passive Scrambler was roughly 1,000 square inches, or about 2 feet by 4 feet wide. However, since it is impractical to drive around with a huge antenna on the roof of your car or truck, then Passive Scramblers can not defeat radar any closer than 1/2 mile from the radar gun, if that.

Speed Measurement Labs of Ft. Worth, Texas, has tested all the passive scramblers from 2 miles away, 1 mile away, 1/2 mile, 1/4 mile and 600 feet away from a variety of X-band, K-band and Ka-band radar guns, and still has not found any radar scrambling performance.