Portable satellite navigation units are becoming very popular items. ("GPS" is one of the most searched for terms on the Web and on ConsumerReports.org, where you'll find our latest test and Ratings of GPS units.)

They're also hot commodities with thieves. Search the online news media with Google using "GPS" and "car break-ins" and you'll see reports from a slew of local police departments. (You can also search for similar news reports using Yahoo, if you prefer.)

Here are some pointers for keeping your GPS and other in-car valuables safe:

• Hide valuables, or better yet, take your portable electronics with you—even if you're going to be away from your car for "only a few minutes." Leaving gadgets in plain sight is risky. It takes only seconds to break a car window, and "smash-and-grab" thieves aren't fazed by blaring car alarms.


• Conceal the mounting arms and any other accessories such as car chargers, headsets, or audio leads. Wandering thieves look for these tip-offs that your car may be harboring portable, battery-operated and pricey gadgets.


• Wipe off the suction cup marks from your windows. Professional, "street-savvy" thieves know these circular marks are indicative of mounting arms and may break in to your car anyway—just in case you hid your GPS unit rather than bother to take it with you.


• Report any suspicious persons lurking near cars. Parking lot attendants, mall security, and the police need to be aware if there are potential thieves working the area.

If you have recently lost a portable GPS unit, I offer my condolences; I have friends and family members that can be counted among the victims of GPS thievery. And try to look at the bright side, if you want to make the best of a bad situation. As we've reported previously, new GPS units offer much more powerful features than older units—and often at lower prices. So if you're shopping for a "replacement" unit, chances are you'll find a good deal. Check our coverage of GPS units on ConsumerReports.org for additional help.

If you've been a victim of a car break-in, feel free to share your story and tips here. You might save others from the experience of losing their valuables.

—Paul Eng

• Keep a record your GPS unit's serial number and/or electronic ID along with your original sales receipt—the items you need when you send in the warranty card to the manufacturer anyway. (And you DO send in those warranty cards, right?)
  
  This might not actually prevent your unit from being stolen. But if it is, having that information will help the police in their investigation—and help you reclaim the unit if it's ever recovered.
  
  Also, you can use that information to alert the manufacturer that your unit was stolen. So if your "lost" GPS unit ever "calls home" (say, to get updates for its firmware or maps) the manufacturer might be able to track it down. Or, at the very least, deny the update to the GPS unit so it becomes less useful.

• If your GPS unit features a PIN code system or other electronic anti-theft system, use it. This won't prevent theft, but at least you'll have some satisfaction in knowing that who ever took it has nothing but an expensive electronic paperweight.