Note: Discontinued. See reviews of the latest models.
A radar detector-savvy bystander stopped to admire the new Jaguar XK convertible test car we were parking and commented about the battery-powered Whistler XTR-540 radar detector on the windshield. In a 90-grand car, he queried, why weren't we packing a high-end radar detector?
Fair question—and easily answered. Although it's a long stretch, a power cord can be routed from a detector on the Jag's windshield to the console's power point. But then it interferes with the air vents and dangles squarely in front of the big touch-screen LCD display. The last distraction needed was a heavy, coiled power cord swaying back and forth, interfering with access to the screen.
The convenience of cordless operation is the biggest selling point for a battery-powered radar detector—and the reason this Jaguar's windshield sported the Whistler XTR-540.
The Whistler XTR-540 runs on three AA rechargeable Ni-MH (nickel metal-hybride) batteries. An auto shut-off feature kills the power after a user-adjustable delay, meaning you won't come back to the car and find the detector down for the count.
Visual alerts are conveyed by a blue-backlit LCD text display whose backlighting is adjustable to a variety of configurations. For example, it can be set to appear briefly during alerts and mode changes and remain off the rest of the time to save battery power.
A radar band can be deactivated through the menu—X-band for example—which is still used only in Ohio. This helps to reduce false alarms.
Radar detection range is mediocre for a cordless model; not something this class is famous for. Battery life proved sufficient for several days of driving and we liked the convenience of rechargeable batteries. The Whistler XTR-540 is worth a look by those who insist on a battery-powered detector and are willing to accept some compromises.