Are Faraday Bags Legal? Signal Blocker Questions Answered

Disklabs ks1
The Disklabs KS1 – a very popular faraday bag in the UK.

At this point it’s no secret that a vast majority of cars fitted with keyless entry pose a real risk to their owners of being stolen, thanks to clever thieves working out how to steal them without even taking the key. This type of vehicle theft, known as relay theft, is continuing to rise year over year, and car manufacturers are simply not doing a good enough job to secure cars fitted with this technology.

Luckily, there are a few measures you can take as a vehicle owner which don’t cost and arm and a leg. One of the best, most cost effective methods to protect your keyless vehicle against theft is to use faraday bags…

But are faraday bags legal? Yes, they are completely legal to own and use. Signal blocking technology in any form might seem like something which is not permitted by UK law, but the police actively encourage keyless car owners to use faraday bags for storing their key fobs inside of. There are a number of police approved faraday pouches on the market , so if you want to make sure the one you buy meets the preferred specification outlined by the police, then be sure to check our complete list in this article.

So where does the confusion around whether faraday bags are legal to own come from?

The Difference Between Active and Passive Signal Blockers

There are a number of signal blocking devices which are entirely illegal to use in the UK, but most of these are forms of what is known as an electronic signal jammer. These work by actively sending out their own signal, in order to block communications. In almost all cases, devices like this are not permitted, although they are quite cool.

On the other hand, Faraday cages and bags are permitted because they work in a passive way. Most of them are essentially constructed from a metal foil lining, which reflects signals and stops them from getting inside the bag. This is the reason they are so effective in preventing keyless entry vehicles from being stolen. Thieves are left without the ability to read the signal being emitted from the key fob, since no signals can enter or exit the faraday bag.

So that’s the debate settled – faraday bags are completely legal, and almost a necessity to own if your vehicle is at risk of relay theft. Let’s take a look at some other myths around signal blocking devices.

Do Faraday Bags Damage Electronics?

No, faraday bags are not harmful to electronic devices placed inside them. They simply block signals from reaching the device, and can actually be used to prevent damage to some electronics

Why Do Faraday Bags Fail?

If a faraday bag doesn’t work, and the key fob’s signal can still be read from inside the bag, then the faraday cage has leaks in it. This usually happens from the sharp keys wearing down the protective lining over time, or from being faulty. It’s essential that you test your faraday pouch regularly to make sure it still works as expected.

Do Faraday Bags Stop GPS?

Yes – well made faraday bags can block almost all signals from entering the bag, from Bluetooth to Wi-Fi to GPS.

What’s The Difference Between a Faraday Bag, Pouch and Box?

They are all essentially the same thing, for the same purpose – bag and pouch are merely synonyms, whilst faraday boxes tend to be larger and less portable, so are better suited to keeping multiple key fobs safe in your house.

What To Use as an Emergency Faraday Cage

If you need to block a signal in an emergency and don’t have a purpose-made device on hand, you do still have a couple of options, although their effectiveness varies greatly. One option is to place your items in a microwave, which tends to be good at blocking most singals when the door is shut. Just be super careful not to turn the microwave on whilst your electronics are inside!

Additionally, another option which is worth considering if you’re in an hurry is a biscuit tin, especially if it’s made from aluminium. Speaking of aluminium, my final idea for creating an emergency faraday cage would be to wrap the object in several layers of aluminium foil.

Faraday bags are completely legal to own and use, so there is no reason not to get one to protect your keyless entry vehicle. The confusion around legality is because a number of electronic signal jammers (which serve a similar purpose) are illegal.

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