Radar guns are devices that use microwave radio and a bit of math to measure the velocity (speed and direction) of moving objects in relation to one-another. Lidar, more commonly known as Laser, does the same thing with infrared light on a narrow beam. It sounds complicated, but it's really quite simple once you boil it down.


Terminology

Radar - Radio Detection and Ranging, microwave radio waves.

Lidar - Light Detection and Ranging, infrared light beams.

LEO - Law Enforcement Officer

LE - Law Enforcement

GHz - Gigahertz

MHz - Megahertz

Hz - Hertz


Microwave Radio (Radar Enforcement)

Radar guns and dashboard mounted radars are the two most common uses of radar by Law Enforcement. Both make use of microwave radio and the reflective properties of radio waves to measure the distance of the target (the speeding vehicle) from the observer (the radar gun). The word "microwave" refers the size of the actual wavelength being emitted by the radar gun. Microwaves are "micro" meaning that the frequency between the crests of the waves are rather short.


Radar Guns

Radar guns are single direction, stationary readings. The benefit of these small, handheld devices is portability and the ability to be used in a variety of situations.


Dashboard Mounted Radar Systems

Dashboard mounted radar systems are mounted to the vehicle with readouts usually displaying on an interface attached to the vehicle's dashboard. The benefit of these systems is that they can be configured to take readings in front of the vehicle, behind the vehicle, and while stationary or moving.


Radar Drawbacks

Radar uses radio waves, which naturally carry a great distance and can be reliably picked up by sensitive equipment. This means that a radar detector with sufficient power and processing ability can detect and alert to the presence of an enforcement signal often miles before the threat emerges.


Radar Jamming

Radar jamming is highly illegal and subject to fines and imprisonment. Our detectors in no way jam radar frequencies, nor does any known, legally sold brand in North America, Europe, the UK, Australia, or New Zealand.


Radar Enforcement Bands

The three most common bands in use for speed detection by radar gun are:


  • X-band 10.525 GHz ± 25 MHz
    • 10.5125 GHz to 10.5375 GHz
  • K-band 24.100 GHz ± 300 MHz
    • 23.950 GHz to 24.250 GHz
  • Ka-band 34.700 GHz ± 1300 MHz
    • 33.600 GHz to 36.000 GHz


Generally, X band is no longer in widespread use (though it has not gone away completely), K band tends to be used at the county level or in smaller towns and cities, and Ka band is in widespread use and is your most active threat.


Infrared Light (Lidar/Laser Enforcement)

Lidar (more commonly known as Laser) guns use a narrow beam of infrared light that provides much greater accuracy than radar guns at the cost of mobility. Lidar guns are typically used by motorcycle LEOs, and officers in squad cars and SUVs tend to use radar, both handheld and mounted. Lidar guns take readings very quickly, and unlike radar they can single out a car in a group for more accurate speed enforcement. Lidar has a short effective range of around a thousand feet, and most officers prefer the vehicle to be much closer before taking the reading, to ensure a quicker and more accurate result.


Officers are trained to aim for a large reflective surface. On a sedan or other smaller vehicle, this will usually be the hood, allowing some potential for the laser detector on our devices to alert to the signal, if the detector is mounted low to the dashboard.


This does not work as well if the detector is mounted closer to the mirror. The laser detector may be completely ineffective if the vehicle has a tall front, such as pickup truck, van, or SUV, as the officer will aim for the grill/headlight area instead due to its much larger size and more reliable targeting.


Lidar Drawbacks

Lidar has a limited range and must be used from a steady, stationary position. Because light can reflect back at angles, the officer needs a good solid beam held on your vehicle for a second or two to pick up a reading. Lidar generally cannot be used from inside of a vehicle, or at an extreme angle, like radar can be used. Officers must be outside of their vehicles or on a motorcycle.


Laser Shifting (Laser Jamming)

Laser Shifting (also known as Laser Jamming) is legal in most of the United States. There are some known states that have laws against Laser Shifting, however you should take note of the specific laws in your region before purchasing our Redline Ci 360c or ZR6 Laser Shifters. Laser Shifting works by temporarily sending back confusing readings to the laser gun, giving the driver a chance to slow down. The longer your shifters are running, the more likely LEOs are to detect a "jam" reading on their gun.


Doppler Effect

The Doppler Effect (also known as Doppler Shift) is a way to measure the velocity (speed and direction) of an object in relation to another object. You have your observer (the radar/laser gun) and your target (the object the radar gun is aimed at; in our case, a vehicle.)


The radar gun emits a short pulse of microwave radio signal at a set frequency (for example: 33.800 GHz, or 38,800,000,000 Hertz) which transmits at the speed of light, and it then measures the reflected frequency from the target object.


The lidar gun emits a short pulse of infrared light and measures the amount of time the reflection of the light takes to return to the gun.


The velocity of the object is determined by some simple division and multiplication, and the final result has three possible answers:


  • The total is 0, the object is stationary (zero velocity) OR the radar gun is perpendicular to the target object (ie; the gun is shooting across the road rather than up or down the road, and the vehicle passes by.)
  • The total is a positive number, the object is moving towards the observer (positive velocity; the pulses are more frequent, meaning the frequency is higher).
  • The total is a negative number, the object is moving away from the observer (negative velocity; the pulses are less frequent, meaning the frequency is lower).


Simple math equations turn these differences into a reading of MPH (Miles Per Hour) or KPH (Kilometers Per Hour) for the police officer, and a directional arrow indicating the direction of travel (away from or towards the officer.)