Frequently Asked Questions
1. Are Radar Detectors Legal?
2. Are Radar Jammers Legal?
3. Are Laser Jammers Legal?
4. Where is the best place to mount my radar detector?
5. What is the best radar detector?
6. What is POP Mode?
7. What is Spectre?
8. What is Laser Atlanta "Stealth Mode"?
9. What are "Jam Codes"?
10. How do radar guns work?
11. How do laser guns work?
12. How do radar detectors work?
13. What is instant-on?
14. What is the difference between X, K, and Ka band?
15. What is VASCAR?
16. What is SWS, SAS?
17. What is photo radar?
18. What should I look for when shopping for a radar detector?
19. Is it OK to run two detectors in the same vehicle?
20. How can I beat my speeding ticket?
Are Radar Detectors Legal?
In the US, Radar detectors are legal for passenger vehicles in 49 states. Radar detectors are illegal in Virginia and Washington DC. Federal Law prohibits the use of radar detectors in all commercial vehicles over 10000 pounds. Radar detector use is also illegal on military bases.
In Canada, only Alberta, British Columbia, and Saskatchewan allow the use of radar detectors.
Various radar detector bans exist in other countries worldwide, check your local regulations.
Are Radar Jammers Legal?
See our page on USA Radar Jammer Laws.
Are Laser Jammers Legal?
See our page on USA Laser Jammer Laws.
Where is the best place to mount my radar detector?
See our article on Mounting Your Radar Detector.
What is the best radar detector?
This is subjective, and will vary depending on individual preferences. The best radar detector for one person might not be the best radar detector for another person. For example, some people want the most advance warning possible, no matter what. Others are annoyed by the additional false alerts of more sensitive units, so they are willing to trade some performance for less false alerts. Decide which detector is best for you by looking at the features of some different units, along with the results of performance testing and reviews.
What is POP Mode?
POP Mode is a feature that was introduced by MPH Industries in their latest radar guns, designed to defeat radar detectors. POP acquires a vehicle's speed by sending out a quick burst of radar. This burst was so short that detectors available at the time of POP's introduction did not alert to it, either due to a sweep rate that was too slow to detect it at all, or due to the short burst being filtered out as a false alert. Fortunately, many radar detector manufacturers have since added POP detection capability to their latest radar detectors.
Radar guns that currently have the POP feature:
MPH BEE 3 = 67ms, K or Ka-Band
MPH Enforcer = 67ms, K or-Ka Band
MPH Z25 = 16ms K-Band
MPH Z35 = 16ms K-Band
Many of the latest detectors can detect 67ms Ka-Band POP reasonably well.
The operator's manual for these guns cautions that "Information derived during the POP burst is non-evidential and to be used for advisory information only...citations should not be issued solely on information derived from the POP burst.
What is Spectre?
See our page on the Spectre RDD.
What is Laser Atlanta "Stealth Mode"?
See our page on Laser Atlanta Stealth Mode.
What are "Jam Codes"?
See our page on Jam Codes.
How do radar guns work?
Radar guns utilize the "Doppler principle" to determine speed.
They transmit radio waves at microwave frequencies, and when these waves strike a moving object, they are reflected back to the radar gun at a slightly different frequency. The gun then "mixes" the reflected signal with the transmitted signal, and ends up with a frequency that represents the difference between the two. Since the difference in frequency is generally a number of hertz or kilohertz, it is in the audible range, hence the term "Doppler tone". The speed of the moving object can be derived by performing a calculation using the frequency of this Doppler tone and the original transmit frequency.
How do laser guns work?
Laser guns do not use the Doppler principle like radar guns do. Instead, they use "time difference of arrival". The laser gun sends out a pulse, and calculates the "time of flight" for the pulse to be reflected back to the laser gun. Since the speed of light is a known value, the distance between the laser gun and it's target can be calculated by the time of flight. The laser gun takes multiple distance measurements, and by comparing the different distance measurements over time, it can determine the speed of the target.
How do radar detectors work?
In a nutshell: Modern radar detectors are superhetrodyne receivers, similar to a scanner. First, they use a microwave horn antenna to receive the radar signal. The radar signal is generally passed on to a first mixer stage, where it is mixed with a first local oscillator to produce an IF. The IF is generally passed on to one or two more mixer and IF stages depending on the design. Finally the signal is detected, and then handled by the processing and control circuitry to produce a visual and audible alert. Radar detectors usually sweep the first LO (and sometimes the 2nd or third too) in order to sweep the different police radar bands for a signal. They will also contain multiple filter and amplifier stages.
What is instant-on?
Instant-On is a term used to describe a particular method of operating radar that can be used to defeat radar detectors:
The officer puts the radar gun in "standby" or "hold" mode where it is on and ready, but not transmitting any radar. When he visually identifies a vehicle that he suspects is speeding, he switches the radar unit to "transmit" mode and targets the vehicle to obtain a speed-reading. If he chooses, he can then switch the unit back to "standby" or "hold".
Here are a couple of ways to defend against instant-on:
1. Choose a very sensitive radar detector, so that when traffic ahead is targeted with instant-on, you'll get a warning alert before it is "your turn".
2. Never stand out in a crowd, or you'll be the one he chooses to target. Try to follow behind someone else who is going the same speed as you are, maybe 1/4 mile behind him. That way, if you encounter radar, he'll get hit with instant-on, and you'll get an alert on your detector telling you to slow down.
What is the difference between X, K, and Ka band?
Here are the basics of what you need to know:
X-Band is the least common police radar. It is rarely used anymore except in a couple of states, most notably New Jersey and Ohio. Some small towns might also use it on occasion. X-Band IS frequently used by motion sensors, such as those that automatically open the doors at your local supermarket, so in most cases this is what causes X-band false alerts.
K-Band probably has the most radar units out there on the road. However, K-Band is also used for some motions sensors too. Treat K-Band alerts with caution, until you have identified the source.
Ka-Band radar is the newest band utilized for police radar. Some sources claim that most of the new units sold are Ka. Generally, with the higher end detectors, false alerts on Ka are rare, so every Ka alert should be treated as police radar until you know otherwise.
What is VASCAR?
VASCAR stands for "Visual Average Speed Computer And Recorder". Although it actually refers to a specific device, the community has adopted it as a blanket term for any speed measurement done by timing a vehicle between two points.
The important thing to note about the VASCAR device is that it can be used to measure the distance between two points either before speed enforcement is done, or simultaneously while driving the patrol car following a suspected speeder, as it interfaces to the patrol car speedometer. When the device knows the distance, it can then calculate the speed by how long it takes a vehicle to pass between the two points.
Accutrack (Robic) is a timing device similar to VASCAR, however unlike VASCAR it has no mechanism for measuring distance, so the distance between two point must be known and entered into the device before it can be used.
ESP (Excessive Speed Preventer) consists of two rubber hoses placed at a specific distance apart from each other on the road. These are attached to a computer than can then determine the speed of a vehicle that passes over the two hoses.
ENRADD (Electronic Non-Radar Detection Device) uses two devices that shoot laser beams across the road. When a vehicle breaks each beam, the device sends the data wirelessly to a reader in the patrol car which calculates the speed.
What is SWS/SAS?
SWS (Safety Warning System) was a system devised to alert motorists of potential road hazards. SWS transmitters can trigger one of 64 pre-programmed alert messages in a receiving unit (radar detector). Unfortunately, use of the system is not very widespread. The best evidence is that "Some 200 transmitters are in use in 33 states".
SAS (Safety Alert System) is another hazard alert system designed by Cobra, and used only in Cobra radar detectors. It is much simpler, only consisting of three possible messages. If the information in one article is true, there are approximately 2000 transmitters spread across all 50 states.
Many people consider the use of these systems to be much too limited, and ignore these features when shopping for a radar detector.
What is Photo Radar?
Photo radar is generally an unmanned device that identifies speeding vehicles using radar, and then takes a photo of the vehicle including the license plate. The violator later receives a ticket in the mail.
Although photo radar is only used in a very few areas of the US, it is very common in some other countries overseas. Sometimes photo radar is weak, and aimed across the road so it is difficult to detect. For weak photo radar such as the Ka Multanova, the best detectors to use for maximum warning are those with "narrow" or "Euro" modes, for example the BEL Target Euro 550, BEL 966R/975R, Or Valentine One 3.825 and up with Euro mode.
What should I look for when shopping for a radar detector?
Shopping for a radar detector can be confusing, as there are a lot of different units available with different features. Really, it all depends on what you want out of a detector. Here are some suggestions:
If you are a lead foot, performance is king. The best radar detector for you will be one of the top models on the market.
However, if you are an average driver who only occasionally drifts over the posted limits and you want some protection from the revenue trap, then one of the budget units might be the best radar detector for you.
Ultimately, you need a detector that you feel comfortable with and that you feel provides you with enough protection. A common strategy is to narrow you choice down to a couple of different models you think you might like, and buy them both (be sure they have a return policy!). Try them both out, keep the one you like, and return the other one.
Optional features such as a compass etc should not be a primary concern when choosing a detector. If you want a compass, then buy a compass. If you want a weather radio, then buy a weather radio. If you want a radar detector, then buy a radar detector! First and foremost, it should detect police radar, and do it well. If it also happens to have other features, then great, but don't let these features distract you from the main goal of protecting you from the "revenue machine".
Always purchase your detector from an authorized dealer! Manufacturer's warranties do not apply to units not purchased from authorized dealers.
Is it OK to run two detectors in the same vehicle?
Not unless you want to risk degrading the performance of one or both of them. One might even cause the other to miss alerts completely. We have an article on why HERE.
How can I beat my speeding ticket?
Sorry but Guys of LIDAR cannot help you there. We are only here to provide you with information that might help you prevent a ticket in the first place. There are a lot of resources on the Internet that deal with the topic of beating tickets, which is beyond the scope of this website.