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Shopping for a Radar Detector

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Are speed traps a fair way of finding and punishing those who choose to break the law; or are they merely income generators that unfairly single out otherwise safe drivers, an example of ill-focused enforcement tactics?

We’re not going to answer that question for you here. Only your conscience and Dr. Laura can weigh in on that question. But if you’ve decided you want a radar detector, here’s some useful advice on how they work, what to look for, and how useful they are in keeping your license and money.

How cops ‘clock’ your speed

Radar guns use a rather simple principle. High-frequency radio waves (in the microwave portion of the spectrum) are broadcast in focus to the general area of a moving vehicle. Due to the vehicle’s speed, the peaks and valleys of the reflected radio waves—which are received by the gun—are distorted (through something called the Doppler Shift). That distortion (a change in frequency of the reflected beam) is equated to a speed by the processor portion of the gun, and the speed is then displayed on the gun’s digital readout.

There are three ‘bands’ that the Federal Communications Commission (FCC) allows radar guns to run on, termed X, K, and Ka by the industry. The X band used to be the most widely used but is now being phased out. The K band is still the most widely used, but most new equipment takes advantage of the Ka band.

While radar guns produce a dispersed signal that can be detected from far away when they’re on, newer instant-on technology makes radar more difficult to detect. However, most units will have no problem detecting instant-on in use for traffic ahead, and some of the more sensitive units will be able to pick up the residual energy needed to keep the antenna ‘warmed up.’

The other method of checking speed that’s becoming more widely used nowadays is laser. Laser guns can’t be used through window glass, so if you see an officer out of the car, perhaps steadying his elbow on the roof, aiming the gun at traffic a thousand-or-so feet down the highway, he’s using a laser-based system called lidar (light detection and ranging). Lidar speed-detection devices don’t use the change in frequency of the finely focused laser (infrared) beam; rather, they use quick beam bursts and timed pauses between the bursts. The changes in the received pauses — along with the angle of the beam — enables the equipment to quickly calculate the exact speed of the vehicle.

Laser poses more of a problem for motorists’ detection, as the beam is so finely focused. When even the best detectors alert you of laser in use, it’s almost too late! Radar detectors with laser features will only be able to pick up a signal if a laser gun is being aimed at a vehicle that’s close ahead, leaving you very little time to respond. If there aren’t any other vehicles nearby on the road, there’s little you can do, though laser jammers are legal (see below)

What about jammers?

Radar jammers do exist — and some are quite effective — but they’re also easy to spot by cops. Before you run out and try to find (or build) one, beware that they’re radio transmitters and thus prohibited by the FCC. Using one is not only a no-no with Trooper Smokey but also a federal offense.

However, it is legal to use laser jammers, as laser transmission isn’t regulated by the FCC. The easiest place for laser guns to get a reading is from a flat, reflective surface, like the front or rear license plate, so these jammer devices use high-intensity LEDs to create a bright halo of interference around front or back of your car, making it difficult for the gun to discern its own reflected signal.

Have radar detectors advanced in recent years?

So will that old, clunky radar detector protect you? Maybe not. If your detector is more than five years old, you might want to upgrade. Radar detectors have become more sensitive overall, and they have more sophisticated means of filtering out false signals. And, for the most part, they’re much better at communicating information to the driver through their displays.

But the main reason why you might want to get a new detector is that the newer models boast improved scanning of the Ka band, which is now in much heavier use than before. Really old detectors might not even scan the Ka band.

How to find the best detector for your needs:

In shopping for a radar detector, your motivation is simple: to know when you’re being monitored, and to avoid tickets! But shopping for a radar detector can be confusing. Model numbers rapidly change with slight variations in features, and sometimes the low-end models appear almost the same as the high-end models, having similar cases but very different innards.

Read objective evaluations. It’s hard to find them! There are also many Web sites that purport to have objective information on radar detectors, but beware, most of them are just out to make a buck on their ‘top-rated’ model. These sites can be great for comparing the features of various models or finding models for specific needs, but, as most of these sites also sell particular radar-detector brands, their objectivity is in question. Consumer Reports doesn’t evaluate them, and some of the other major magazines hire out roundup evaluations from people who aren’t objectively removed from the industry.

For unbiased performance evaluations, we recommend Car and Driver magazine. In its evaluations, the magazine independently purchases its test units, rather than relying on manufacturer-supplied ‘demo’ units that may have been tweaked for ‘improved’ performance, and actual staff members learn about the technology and evaluate the units’ performance.

Car and Driver rates the Valentine One highest among popular detectors. The Valentine also has a loyal following among serious enthusiasts and auto-industry affiliates. Otherwise, the Escort 8500 is also a top-rated unit by C/D and others. “Still, none of them can touch the Valentine,” said Andre Idzikowski, C/D’s in-house expert on radar detectors. Idzikowski explained that the Valentine’s top performance and excellent interface/display again made it the magazine’s top choice in the most recent round of testing.

Test out the detector’s display and interface. Make sure you can live with the alerts. They should be loud enough and with a quick glance you should be able to pick out added information from the display. For instance, many think the Valentine One stands out from other top-rated models by offering two straightforward display features that Valentine developer Mike Valentine holds a patent on: a directional-arrow system and a bogey counter. The directional-arrow system shows you which direction—front, sides, or back—the alert is coming from, and the bogey counter keeps a count on the number of threats (or false signals), so if a new signal is detected in addition to those, you’ll know. Idzikowski explained that Escort has introduced an ‘expert mode’ on some models that supplies similar information, but he argued that it’s not nearly as easy to read at a glance as the Valentine.

You get what you pay for. Generally, price directly correlates to performance. Companies are trying sell low- and mid-priced models by adding gimmicks like built-in compasses, GPS capabilities, voice alerts, or weather radios. But that doesn’t make the unit any better at keeping the ticket pad away. The difference between a $100 radar detector and a $400 unit is usually in real speed-trap performance, not features. “The more expensive detectors are not much more sensitive than the cheap ones, but they have real filtering circuitry,” added Idzikowski, who explained that some of the cheaper detectors, rather than incorporating filtering circuitry, incorporate circuitry that effectively just cranks down the sensitivity to cope in areas with multiple signals or interference. The high-end detectors’ more sophisticated (and costly) filters allow the sensitivity to remain high while culling out other signals.

People often fail to realize that a speeding ticket is not only the initial $100 or more in fines. It also means increased insurance costs for years. So the real, indirect cost of a speeding ticket can be thousands of dollars — that, and a threat to your driving privileges. When you think of it that way, $400 isn’t a lot of money. For some, it’s just a smart investment; but for others it begs the question, how much is your license worth?

Here are some of the major radar-detector manufacturers:

Bel (

Cobra (

Escort (

Uniden (

Valentine (

Whistler (

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