There has been a lot of hype related to so-called remote “signal jamming” in the news of late. Signal jamming refers to the shady and highly illegal practice of using a remote control device – such as the ones used to open garage doors or entrance gates – to “jam” the signal transmitted by the remote that you use to lock your car, arm its alarm, etc.
Let’s first take a look at the technology behind it all. The hand transmitter – or remote control, as it is more commonly known – transmits a RF signal that is picked up by a receiver. The receiver, which is basically a tuned circuit, in turn converts this signal to an output which will then be used to operate a gate motor, activate a car’s central locking, or whatever the case may be. In South Africa the frequency band on which all remote devices operate is 433MHz, as decided by the regulator for the South African communications sector, ICASA. This band is shared by all RF devices.
As illustrated in a recent television news segment, criminals abuse this novel technology by pressing and holding their remotes at exactly the same time as an unsuspecting vehicle owner is endeavouring to remotely lock his or her car, or to arm the vehicle’s alarm, and in so doing leaving the car vulnerable to intrusion. It must be remembered that the signal sent out by these transmitters is comparatively small, and can thus be swamped by interfering signals.
Naturally, the raison d’être of remote controls is to provide the user with convenience and peace of mind, and every possible precaution has been taken to ensure that remote controls are as secure as possible, with certain gate motor manufacturers even implementing revolutionary rolling-code technology to prevent “code-grabbing”, another dastardly practice favoured by modern criminals. Remote controls using rolling code technology never transmit the same signal twice, dramatically increasing the security of RF communication and rendering code-scanning devices completely useless.
However, as discussed earlier, even these highly secure remotes are required to operate at a frequency of 433MHz, and as such criminals have been known to use them for signal-jamming.
Most vehicle manufacturers equip their cars with some sort of confirmation signal, be it a beep, double beep or flashing of the headlights, to indicate that the vehicle in question has been securely locked or the alarm has been armed, etc. I therefore implore all vehicle owners to listen carefully for these confirmation signals before leaving their vehicles unattended. It is better to adopt a pro-active approach when dealing with this new breed of tech-savvy criminal.