Radar Gun Glossory

Directional Antenna – an antenna that transmits or receives signals only in a narrow angle.

Doppler Radar – A radar that detects and interprets the Doppler effect in terms of the radial velocity of a target. The signal received by radar from a moving target differs in frequency from the transmitted frequency by an amount that is proportional to the radial component of the velocity relative to the radar gun.

Fast Speed Tracking – Track both the strongest and the next faster vehicle at the same time, both in the moving and stationary mode of operation. For example: Track the sports car passing the 18-Wheeler. Most of Decatur Police Radars offer Fast Speed Tracking.

Ghost Effect – Sometimes when a radar signal hits a valid target, clutter may originate from multipath echoes created due to signal reflection from the ground, atmospheric particles or due to ionospheric reflection and/or refraction. The clutter is very bothersome because it appears to move and behave just like another normal target, thereby creating a “ghost”. Using a ground map of radar ‘s surrounding and eliminating all echoes that appear to originate from below the ground may help solve the “ghost” problem.

LASER – Laser is light, so this is not a microwave radar band. The laser radar guns operate in the infrared region, which is invisible to your eye. The infrared region is extremely high in frequency, so it is typically described in terms of wavelength.
LIDAR, also is known as Laser Radar , LADAR – Acronym for Light Detection And Ranging. With a Lidar device, one can measure speed, distance, rotation, chemical composition and concentration of a remote target, such as a vehicle.

K-Band, Ka-Band, K-Bands – Police Traffic radar has been assigned specific frequencies by Federal Communication Commission (FCC). These frequencies are designated by the letters -S, X, K and Ka and are referred to as bands. Ka band is the newest frequency used in police radars. Ka band is a wide band which allows police radar guns to operate on a multitude of frequencies. Ka-band: (Frequency 33.4 -36.0 GHz; Wavelength .344 inches)

Moving Radar – is radar that clocks vehicles while the patrol vehicle is moving. Typically, the targets are those approaching in the opposite lane of traffic but, depending on the radar model, can sometimes be used to clock vehicles going away from the patrol vehicle in the opposite lane or even moving in the same direction (for example, Decatur Genesis II Directional Police Radar or its most recent cousin- Decatur Speed Trak Police Radar w/ K-band Directional Antenna). These moving radars also “clock” the patrol vehicle by measuring the speed of the ground passing beneath the patrol car and interpreting this as the patrol speed. This speed is deducted from the closing speed of the target thereby giving its speed.

Same Direction Tracking – Tracking vehicles from behind or in front of the Patrol vehicle going the same direction while the Patrol vehicle is moving. All Decatur Police Moving Radars and Decatur Polie Radar Guns offer Same Direction Tracking mode.

Same Lane Radar – Uses dual antenna moving radar to clock vehicles ahead or behind a rolling cruiser.

Stationary Radar – is operated from a stationary position. Virtually all radars work in this mode and some will also work in the moving mode. Most of sports radar guns and handheld police radar guns are stationary radars. VASCAR – an acronym for Visual Average Speed Computer and Recorder. This is little more than a glorified stopwatch, whereby the vehicle is timed over a set distance (for example over two white markings in the road surface or over two bridges) an average speed is then automatically calculated. No radio waves or beams of light are emitted and thus this system is unable to be detected by any form of electronic detector.

X-band Radar – Radar Frequency tolerance 10.525 GHz25 MHz Frequency range 10.500-10.550 GHz. X-band Radars have been around since the 1960s and operate on a single frequency. Typically their operational range was 20 mph- 90 mph or more. U.K. and Australia ceased using X-band Radar many years ago when the frequency was licensed out to other industries that required access to microwave transmitters (alarm systems etc.)

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