Q: How come my radar detector doesn't go off sometimes when I drive right by a cop car?
A. Radar detectors can detect radar but not police vehicles. There's a good chance the police car wasn't radar-equipped (90 percent carry no radar).
Or if it was, most officers shut off the radar while they're out of the car on a traffic stop or when using it in instant-on mode. With the radar off there was no signal to detect and your detector stayed quiet.
Q: Why am I getting so many false alarms on K band?
A. On the highway, Blind Spot Monitoring (BSM) radar in nearby cars is probably to blame. These systems spot a vehicle in the adjacent lane and warn if a lane change is dangerous.
In town, commercial automatic door openers routinely cause false alerts. Other K-band false alarms are caused by traffic-sensing radar (TSR) that monitors traffic flow and volume.
Many newer detectors recognize TSR radar and GPS-enabled models can lock out door-opener radar. BSM radar is harder to combat but some detectors use firmware to identify and ignore it.
Q: What's the best radar detector?
A. It used to be the one with the longest range. Now the best radar detector is one that resists false alerts while still alerting to real threats well in advance.
Models with GPS have a big advantage because they can lock out nuisance signals from radar-controlled door openers. The same technology lets them dial back sensitivity when it isn't needed and restore it at higher speeds, further reducing false alarms.
Q: What's the attraction of a built in detector?
A. Security is one advantage; we've yet to have a remote (built-in) radar detector get stolen. Regardless of its value, if a radar detector is visible, eventually some twit will smash the glass and steal it.
Another advantage of remote models is discretion. Detectors are legal in 49 states, but some cops disapprove. Get stopped by an officer like this and you're more likely to be cited.
They're pricier than windshield-mounted models. For example, the range-topping Escort portable is the Escort Redline 360c ($749) while the least expensive Escort remote is $2,999, plus installation.
Q: I typically drive 10 miles of back roads then 30 miles of the Pennsylvania Turnpike twice daily. What's the best way to set up my Radenso Pro M?
A. Pennsylvania is unique—only state troopers are allowed to use radar and all of it is K-band. (Unfortunately, BSM (Blind Spot Monitor) radar uses the same K-band frequency.)
You'll want to optimize K-band performance while minimizing false alerts. Some detectors have settings that can be tweaked to accomplish this. Many Escort models, for instance, have an Auto LoK setting that dials back K-band sensitivity. Escort GPS-enabled models adjust sensitivity automatically, further reducing false alerts.
Q: Does radar work if the patrol car is moving?
A. Yes and moving radar is far more lethal than stationary radar. Most of these radars have an antenna in front, another in back, giving them front-rear coverage.
They can also track same-direction vehicles in front of or behind the rolling cruiser. Many also can target the fastest car in a pack, making it hard to hide behind slower vehicles.
Q: I've heard that putting the detector up high on the windshield gives it better range. Is this true?
A. No. It may seem logical but in 30 years of testing detectors, we've never seen range improve by altering mounting height by a few feet.
An extra 50-plus feet might make a difference on rare occasions, but a radar detector is more affected by orientation than height. Keeping it level and pointed down the centerline of the vehicle will maximize range.
Q: I want a detector that runs on batteries so I won't have to deal with a power cord. How do they stack up against the rest?
A. There was only one cordless, the Escort Passport Solo S4, and it's been discontinued. Although battery-powered, it could use a power cord to run on vehicle power.
Its range was weak. Battery-powered detectors have a duty cycle, shutting them off for a few milliseconds at a time. This extends battery life but decreases detection range significantly.
Q: Driving in California, I've never seen anything other than Ka band be a real alert. Am I safe turning off X and K bands unless/until I leave the state?
A. Shutting off X band west of the Mississippi is fine, but doing the same on K band isn't risk-free. Although the California Highway Patrol uses Ka band exclusively, several thousand K-band radar units remain in service, some of them in California.
But if you're being pestered by K-band false alarms, in your area the risk is low enough to make the move worthwhile.
Q: On the highway, why does my detector alert sometimes when I don't see a cop car?
A. If it's an X- or K-band alert it may be an automatic door opener. The best radar detector can spot these from a half-mile away or more. A short K-band signal that quickly disappears could well be from Blind Spot Monitoring radar in a passing vehicle.
If it's a Ka-band alert, most likely it's instant-on radar working traffic up ahead. With the radar on hold, the officer triggers it at close range and gets a speed almost instantly. Instant-on radar accounts for big percentage of all speeding tickets.
Q: How come my detector doesn't alert to red light cameras?
Until recently most red light cameras were triggered by pavement sensors. With no radar present, there was nothing to detect.
The trend now is radar-control, much cheaper to install and maintain. Radar makes the cameras detectable and a few detectors can spot them. A better idea: one with GPS and advanced firmware to cope with false alerts.
Q: What's the best radar detector that will keep me from getting flashed by a red light camera?
A. A GPS-enabled model is your best bet. Look for one with good sensitivity on Ka band, the most commonly used frequency. GPS eliminates door-opener radar alerts and warn of cameras.
And choose one with firmware that reduces nuisance alerts from BSM radar. We compared several of these in a recent test.
Q: Sometimes I drive by a cop aiming his radar gun at me and my detector doesn't go off. How come?
A. If he was holding it to his face and peering through an aiming reticle, it was a laser, not radar. The invisible beam of light is nearly impossible to detect since only a direct hit will set off a detector. The license plate or grille are the most common points of aim, and the narrow laser beam often never reaches a dash-mounted detector. The only defense is a laser jammer.
Jammers aren't allowed in 14 states, but many drivers are willing to chance a minor infraction in exchange for dodging a far more expensive speeding ticket.
Q: Do Rocky Mountain Radar detector/scramblers really work?
A. We've yet to test one that jams anything. Not that you'd want to use a radar jammer, given that it's a federal felony even to possess one.
We broke the story on Rocky Mountain Radar in 1993 [The Little Jammer That Couldn't, Automobile Magazine] and have tested many of its wares in the years since. Aside from being marginal at detecting radar, none exhibited any jamming effect on radar or lasers.
On the other hand, laser jammers are legal in many states.