I think this is the second time this has come up on this forum.

I too keep my (Mazda) keys in a steel cashbox, being under the impression that this "Faraday cage" was sufficient security. I am a loss to know why a pouch presumably with some kind of metal mesh is any better.

Can those with some expertise please advise?

NOT an expert, but I think the solid wall tin can acts as a signal amplifier.

where a grid like the faraday cage will only allow certain frequencies through, similar to microwave doors they have a grid that will not allow microwaves through the door but other frequencies will go through

so a grid is better than a solid sheet afaia I think a copper grid works best rather than steel as certain transmissions can be made through steel

Edited by bolt on 06/07/2019 at 13:12

I can see two possible problems with a tin:

a) Small gaps between the lid and the body of the box. You'll often see a fine metal mesh around door seals on equipment that needs to exclude RF.

b) Rust or paint preventing good electrical contact between the box and the lid.

The whole tin acts as a signal amplifier so should increase the distance of usable transmission from remote to car, which is the reason mesh lined bags or boxes are recommended as the mesh is made to block the transmission, similar to coaxial cable, shields and prevents cable interference

>>you still need a hand free to open a door

Some fancy sensor allows the boot, tailgate to open with a "Kick Sensor" under the boot of the car - Some Fords, VWs, JLR........... - Other makes are available from quality retailers countrywide

I'd be interested to know - is there anyone on here who is actually glad that they've got keyless entry and start? Or is it yet another answer to a question that not many people are asking?

I must have had one of the first cars to have remote central locking (a Renault 20 in 1980) and have had it on every car since. But not once in nearly 40 years have I wished I didn't have to get my keys out of my pocket and go 'plip'. (If I'm laden down with shopping I normally have a trolley - and in any case you still need a hand free to open a door.)

Never had a car with keyless. With all the press coverage (for a number of years) about keyless cars being easy to steal, I wouldn't buy one. However I fear that manufacturers will make this standard across the ranges, so we won't have any choice.

Like Avant, I like remote central locking, but never once have I wished I had keyless. Remote central locking got round the issue of de-icing door locks in winter (a solution to a real problem). However I don't know the problem that keyless solves. So what if you've got your hands full, put your shopping on the ground to open the car, it's a lot more convenient that having you car nicked.

Going back to the 1970's, 80's, 90's car theft was rife. It was virtually wiped out with the introduction of engine immobilisers (with chipped keys). Keyless systems seem such a backwards step.

Every week in the "Ask HJ" page there are answers about keeping keys in faraday bags. That's a far bigger hassle than using a plipper and putting a key in an ignition switch.

End of rant. Anyone disagree with the above?

Faraday bags are not all universal and don't block every frequency, aluminium foil blocks a phone signal

They are made for specific frequencies, where one will cancel out car remote signals another will cancel phone signals, not block but cancel, it depends (from what I`ve read) on the thickness and size of grid and material used

Aluminium foil can be part wrapped around phone or router to increase signal strength but not wrapped all around that would block the signal, some people with routers put foil halfway around aerial of router to strengthen signal

However I don't know the problem that keyless solves.

Are you a single man fiestaowner?, i only ask, because if you got a womans perspective, you'd have a better understanding what 'problem' keyless entry solves. Women, in general, don't keep keys in their pockets, they tend to be in a handbag. Now if said handbag is small and dainty, and is the only thing being held, no probs. But if she has bags full of shopping, while you could put it down, that is not very convenient at all, and may result in breakages. Or if she is trying to keep hold of kids in a large car park, letting one go to try and fish a keyfob out of the handbag could result in the kid running off with all manner of consequences, most of which wouldn't be desirable. And if, like my wife's, the handbag is enormous and bulging with all manner of stuff (you wouldn't believe!), that presents a very real problem of trying to dig out said key, possibly in the cold and the rain. If on top of that, (like my wife again) the woman in question has to use a walking stick or crutch, the problem is magnified greatly.

I have not had one of those things inflicted on me but is it not possible to take the battery out the fob and then just open the car manually with the key? Or do the manufacturers no longer provide a physical key and a lock to put it in?

bestride.com/news/technology/how-to-unlock-and-sta...d

I have not had one of those things inflicted on me but is it not possible to take the battery out the fob and then just open the car manually with the key? Or do the manufacturers no longer provide a physical key and a lock to put it in?

My alarm goes off in my car if I open the door manually with the key and the alarm has previously been set with the keyfob. It does have the nice option of being able to lock the car without setting the alarm if locked with the key manually, but the keyfob still has to be pressed while starting the car to disarm the immobiliser. I'm talking 2005 technology though, not sure how things work on the new systems.

Edited by corax on 07/07/2019 at 12:45

There are two factors going against you with teh steel cash box. Firstly, the steel will have fairly low conductivity and secondly it is ferromagnetic. An aluminium box would most likely provide adequate shielding.