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Drivers locked out of their cars at Royston Tesco

bbc.co.uk

51–60 of 102 posts

Re: Drivers locked out of their cars at Royston Tesco

#51
post #42

Earlier quoted context omitted.

Still sounds pretty mysterious to me. This kind of event is rare, and the source of the interference is (currently) a mystery. I’d love to pop by with a HackRF and directional antenna if I lived anywhere near-by!

It's not that uncommon actually. Even at my car dealership this is a common problem. A couple hundred cars with the same keyless entry system parked in the same lot. All those cars are actively scanning for their key fob, which causes all sorts of RF collisions. I've gotten used to having to use my physical key when picking up my car at the dealership.

the cars are transmitting? are you quite sure?

Re: Drivers locked out of their cars at Royston Tesco

#52
post #23

The ham radio folk, of which I am one, are probably down there with scanners now and could tell you the problem ;-) Before I was a licensed ham I put together a little AM transmitter with a 9v battery connected to a portable cd player. I was shocked that I could pick up the signal several miles away (and yes I know hams, very bad behaviour, I was ignorant). I'll put my money on a new antenna having gone up nearby.

As a fellow ham I’d probably stay away these days in fear of being labelled the cause of the problem.

Re: Drivers locked out of their cars at Royston Tesco

#54
post #9
post #4

It's odd that no one has analyzed the 433 MHz band to find out what is interfering with all these signals. It's most likely to be a bit of misbehaving equipment permanently on a channel.

Presumably they've given Ofcom a call and they'll go look whenever they get around to it, but some noise on ISM is probably not treated as an emergency.

If you look at the Ofcom schedule it says that 433Mhz ISM devices must accept harmful interference. So you’re probably right. They aren’t safety critical systems.

Re: Drivers locked out of their cars at Royston Tesco

#55
post #2

> "I thought it was some kind of alien phenomena." Any sufficiently advanced technology is indistinguishable from magic. For some (a lot?) of people, keyless entry seems still to be an advanced technology.

I have an EE degree and I firmly consider even the simplest forms of radio communication insane magic.

Re: Drivers locked out of their cars at Royston Tesco

#56

It'll be someone using a 'jam, listen, and replay' device to unlock and start keyless cars so they can drive them to a port and steal them. Pretty much every week a car is stolen this way from my street. I now always take the engine management fuse out of the fusebox when parking my car so at least the car can't start when a thief pulls this... They tried anyway though!

> jam, listen, and replay

Does that actually work? I thought the fob would contain some kind of private key that's used in a challenge/response scheme with the car, precisely to avoid the replay attack?

Re: Drivers locked out of their cars at Royston Tesco

#57
post #13

Earlier quoted context omitted.

Cars not having physical locks on doors or for ignitions anymore is one, I assume.

Does such car exist? (Tesla Maybe?)

Modern (all?) Teslas do not have a physical key hole at all, you need to use a key card or key fob or the app (which works over bluetooth)

Re: Drivers locked out of their cars at Royston Tesco

#58

Article from a few years ago about a neon sign switching-mode power supply that was causing interference on the 433MHz frequency (as well as others): http://www.arrl.org/news/view/amateur-radio-sleuthing-pins-d... And “an inventor” who's make shift doorbell was causing problems on 355MHz: https://hackaday.com/2019/05/15/the-great-ohio-key-fob-myste... Trouble with these devices is they rely on all applications just t…

Would it be possible to shield the external noise somehow, eg with some foil in a cone shape?

Re: Drivers locked out of their cars at Royston Tesco

#59

Does UK still have those vans that drive around, looking for unlicensed TVs? If so, could one of those be repurposed? I suspect they have fairly wideband scanners.

I remember this being a common fear in the UK during the 90s. I cannot report on whether such vans actually existed.

Re: Drivers locked out of their cars at Royston Tesco

#60

It'll be someone using a 'jam, listen, and replay' device to unlock and start keyless cars so they can drive them to a port and steal them. Pretty much every week a car is stolen this way from my street. I now always take the engine management fuse out of the fusebox when parking my car so at least the car can't start when a thief pulls this... They tried anyway though!

> jam, listen, and replay Does that actually work? I thought the fob would contain some kind of private key that's used in a challenge/response scheme with the car, precisely to avoid the replay attack?

It's a real-time relaying, for precisely the reason you suggest, but yes it does work.
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