Through the years we have received thousands of questions about radar and laser technology that law enforcement use.

We have selected the most commonly asked questions in an attempt to give you a better understanding of the subject

Q Are radar detectors legal?
A They are legal to use in New Zealand have been for over 40 years. Many Police involved in traffic work believe that radar & laser detectors slow drivers down.

Q Are radar / laser jammers legal?
A Here in NZ it is an offence under the Land Transport Act Revisions of 2011 to Jam speed measuring equipment.

Q I just passed a police car and my radar detector didn't go off?
A Not all police cars have radar or laser guns.

Q There are places where I drive and my radar detector goes off with no police in sight. Why?
A The FCC in the USA and ITU in NZ allows other uses on radar bands used by police. Most commonly this is found on X band (10.525 GHz) and it is called a false alert. Some common false alerts are caused by automatic door openers, burglar alarms, terrestrial microwave towers. Poorly made radar detectors in other cars can also cause your detector to false alert. No radar detector is completely "false alert" proof.

Q How many radar and laser guns are in use in New Zealand and which band is most popular?
A There are approximately 1100 radar systems and 163 laser guns in use. According to the data we received as at 2006 there is no X band radar left in operation. All the Radar in the HWP Cars operate on the KA SWB at either 34.6Ghz 34.7GHz or 35.5GHz ±100Mhz. There are approx 70 non radar Pole Camera locations with 14 camera's rotated through them and approx 70 Mobile speed camera Vans or station wagons. These latest Vans (2011) run a new Digital Low Powered Pulsed K band signal which is very difficult to detect. The operation frequency is 24.100GHz. ±100MHZ

Q What is the most common range an officer uses a radar or laser gun?
A Officers, by law, must establish a "visual tracking history" of your car. This means they must be able to identify the make and model of the vehicle before assessing speed with a radar or laser gun. This is usually 600 metres or less. In most instances, officers rarely use a radar or laser gun past 1 kilometre. The maximum range of the Prolaser 2 is 610metres.

Q I got a ticket and I want to use as a defense the calibration of the radar gun. Is this a good idea?
A The US courts have consistently ruled, i.e. Connecticut v. Tomanelli (1966), Wisconsin v. Hansen (1978) that tuning fork verification is adequate to insure the accuracy of the radar gun. Officers before starting a shift, should strike the tuning fork to verify the correct speed stamped on the fork appears on the speed readout of the radar gun. Further, N.Z. radars and tuning forks need to be verified annually by a certified technician and that notarized certifications pertaining to radar gun and tuning fork accuracy be made available to the public.

Q Do radar guns cause cancer?
A This came from a court case brought by two Connecticut state troopers claiming radar guns contributed to testicular cancer. The courts found no medical evidence to substantiate the claim. The answer is no!

Q Sometimes my radar detector gives a long range warning to radar guns; sometimes it doesn't. Why?
A Different radar guns transmit at different output powers usually from 5-50 mW. If you are standing 30 metres away from a friend and they whisper, you can't hear them. If they shout, you can. In other words, your friend is transmitting at two different output powers. Radar range is adversely effected by humidity, elevation, particulate matter in the air, rain, and snow.

Q What is "instant on" or "pulsed" radar?
A This is a method of momentarily triggering the radar gun "on" and then triggering the gun "off". The normally occurs is less than a couple of seconds. Instant on triggers were developed, in part, to thwart radar detector use. Some radar detectors don't report "instant on" at distances greater than 300 metres.

Q What is the radar detector-detector and why is it important?
A The radar detector-detector is called the VG-2 and it looks for a common IF emission of radar detectors at 11.55 GHz. Many of the detector makers have changed their common IF and can't be detected. The industry calls this "undetectable". Detectability is of little use for cars in the New Zealand as detectors are legal.

Q I'm going to court and plan to challenge the officer's training and understanding of radar. Good idea?
A The US courts have consistently ruled it is not necessary for an officer to have a comprehensive knowledge of Doppler radar but receive adequate training and certification, Honeycutt v. Kentucky (1966), Ohio v. Wilcox (1974). If the officer is certified, you will have little luck! Ditto for N.Z.

Q Do radar and laser jammers work?
A There is one active radar jammer that returns a variable doppler shift that does have success in jamming K band radar guns. The Phantom RCD. There are several laser jammers like the Blinder M-10 that are also very effective in Jamming All current laser guns used by the Police.

Q I got a laser ticket and my detector didn't even go off. Why?
A Laser is increasingly used in metropolitan areas as it can pinpoint one vehicle in a group of traffic while radar guns can not. At 200 metres, the laser guns 904 nanometer, infrared beam is only 40 cm wide and does not scatters (bounce off objects like radar). If your laser detectors receiver is out of this 40 cm beam width, chances are it will not alert to laser's use. If the laser gun were pointed directly at your detector, it would alert. The chances of getting any advanced warning of laser being aimed at the car in front of you are slim. Remote Laser Jammers like the M-10 are very effective in detection of Laser as they are mounted inside the target area.

Q Are the claims of 360s radar and laser protection true?
A For radar, the claims are valid. The letters in RADAR stand for RAdio Detection And Ranging meaning a radar transmission is very similar to your favorite radio station. Radio waves bounce off metal signs, the truck in front of you, buildings, and other reflective objects. Although radar detectors have only a front facing radar antenna (with the exception of the dash mounted Valentine One which has a front and rear facing antenna), a radar transmission from behind you will most likely bounce into your radar detector's front facing antenna. Laser is another issue by it's very directional and highly collimated, monochromatic nature. If the detector were outside of the vehicle, most detectors will alert to laser from the front or rear. Rear alerts are hampered by the attenuation of the glass in the rear window. Side laser alerts are rare , and laser can't aquire your speed to the side.

Q I've heard of a new radar band that radar detectors can't see. Is this true?
A Radio frequencies used by law enforcement radar guns are controlled by the Federal Communications Commission, FCC, and not by the individual States or Countries. There are three radar bands currently used by police and approved by the FCC consisting of X band at 10.525 GHz, K band at 24.150 GHz, and Super-wide Ka band at 33.4-36 GHz. The FCC does not control the use of laser guns. The United States Food and Drug Administration certifies laser guns for eye safety under CFR 21, subpart 1040 and 1041. Laser guns operate on a single, infrared, wavelength of 904 nanometers. When you hear this rumor, the driver most likely encountered "instant on" radar their detector did not see. Radar frequencies used in NZ, Australia, UK and Europe are the same as those used in the USA and are all controlled by the FCC.

Q How can I be sure my radar detector is operating properly?
A Find a supermarket with an automatic door opener and drive toward it with your detector on. The automatic door opener should make your radar detector alert.

Q Will my radar detector see VASCAR?
A VASCAR stands for Visual Average Speed Computer And Recorder and is a timing device that times your vehicle from one predetermined point to another. It is like a stop watch and puts out no signal. No radar detector can warn you of VASCAR. VASCAR is commonly used in Pennsylvania as local law enforcement departments can not use radar guns by state law.

Q If I see an officer targeting me with radar and my detector alerts, can I slow down in time to not get a ticket?
A Radar travels at the speed of light which is 186,000 miles per second. In one second, the time it takes to blink your eyes, light travels seven times (7.44 times to be exact) around the world. Your speed reading on the radar gun is instantaneous and you do not have time to slow down.

Q If officers must use a tuning fork to insure radar gun accuracy, what do they use for laser guns?
A Laser guns compute speed by transmitting "Pulsed Wave", PW, infrared emissions at a predetermined rate, usually from 100-238 pulses per second. These pulses bounce back to the laser gun and the gun's computer remembers each pulse, i.e. when it left and when it returned. This is called "flight time". If the laser gun knows time and distance, it rapidly computes speed of the target vehicle, usually in less than 1/3 of a second. Consequently, the gun must accurately compute distance. Prior to using a laser gun for speed enforcement, the officer should perform a "Delta Test" for distance accuracy using constant distance reflectors at a fixed location. The gun should read the same distance each time prior to use. The admissibility of laser enforcement has been upheld in New Zealand Courts.

Q Will my radar detector protect me from a photo radar ticket?
A Photo radar is an automated system with a radar gun tied to a camera. It came originally from Germany where it is called MultiNova. Presently, photoradar systems used in New Zealand use either Ka band at 34.6 GHz. The radar guns are angled across the highway between 20-22s? degrees. These photoradar guns have a very low output power from 2.5 mW and below. Due to the low output power of the photoradar guns, most radar detectors will give no advanced warning. Only the latest detectors from Valentine Research & Beltronics will provide adequate warning of Speed Cameras. Typically you can expect it to fluctuate between 300-600 metres.

Q I've heard putting tin foil on your hubcaps keeps a radar gun from getting a speed reading. Is this correct?
A Drivers have tried everything to foil radar gun from fish depth finders, to neon lights, to tin foil on hubcaps. None of these home remedies work. There is only one way to fool a radar gun and that is by disrupting the "Doppler Shift" of the return signal.

Q Is the range of a dash mounted radar detector the same as a remote that mounts behind the grill?
A Frontal performance of dash and remote detectors is almost identical. However, rear reception with a dash model is superior to that of a remote. Some remotes offer a rear receiver. Remotes can't be seen. Yearly, 1 in 5 dash models are stolen. Remotes are always a good option although inevitably are more expensive to buy and require a professional installation.