Keyless entry fobs result in rash of vehicle thefts

in security on 2015-05-11 14:56 (#8TR4)

As vehicles become more technologically advanced, thieves are becoming technologically savvy, too. Cars with a hands-free key fobs typically unlock a car within about 30 centimeters. But across the USA, thieves have begun using a device called a power amplifier to help unlock cars. The amplifier, which can cost less than $20 over the Internet - takes the signal from the car and projects it as far as 100 meters, so your car can find your key fob in your purse, pocket or the table where you dump your stuff when you come in the door.

In Toronto, Los Angeles, Long Beach, New York, Springfield, and more cities, police have reported a spike in thefts from Toyota and Lexus SUVs, Priuses, and more vehicles, all parked in owners' driveways with no signs of damage. As more people buy cars with these no-push key fobs, what's the solution to stopping this type of break-in? "Use a microwave" or wrap your keys in aluminum foil. The heavy metal cages block the signal. It's another case of convenience becoming a two-edged sword.

Re: I can't say I understand this 100% (Score: 1)

by tanuki64@pipedot.org on 2015-05-12 00:46 (#8VQ5)

Didn't you read my post? Apparently not. I have no problems with the device being bidirectional. But a repeater cannot repeat what it cannot receive. The thieve stands with the amplifier by the car. The cars sends its request. According to the article this signal it is so weak that it can only be received by the key when the key is in 30cm distance. The amplifier boosts this signal so it can be received by the key in 100m distance. Fine. The key might happily answer.... 100m away. But what good is this, when the key signal is also so weak that it can only be received in 30cm distance?If the key signal is too weak to reach the amplifier, it cannot be amplified. Bidirectional or not. Is this so hard to understand?

If the key has a reach of 30cm and the car has a reach of 30 cm... where do you place the amplifier that it can amplify both signals? Either the answer signal from the key is by far stronger than that of the car. Why? Or the amplifier is much more sensitive and can receive the car and/or key signal over a much larger distance than the key can, but this is info missing in the article.