Car security

forgotmyname

Car_54 said:

Do you really understand the physics?

Not only do I understand I went a step further as anyone that comments on the subject should and tested the 'old wives tales'

of what works and what does not.

I tested the fridge, phone and car keyfobs still work. Rubber seals and a lot of plastic in the panels these days does not create
a metal to metal seal.  The same with the microwave, not a metal to metal seal on the door so a phone and car fob still work.

Tried metal biscuit tins with the same results, because it's not a continuous seal between the lid and the base the signals
still escape. The pouches work 'IF' properly sealed but many don't and the ones that do when new sometimes break
down through usage.

Not the complete list of stuff I tested but the one that worked most reliably was wrapping in kitchen foil but I do have an unknown
brand that failed for some reason. Maybe it's got a plastic coating preventing a metal to metal seal?

MattMattMattUK

I tested eight different top selling models of key pouches which claimed to be Faraday pouches for a customer as they wanted to use them as part of a marketing campaign. Six did not work at all, literally did nothing, one slightly attenuated the signal, the other worked out of the box but within two weeks or usage it leaked enough signal to be able to unlock the cars. I was not even using signal repeaters or boosters, just walking in proximity to the vehicle, I imagine that with the correct signal boosters none would have worked on day one. 

We also tested a box, it worked, again only in proximity tests, but I did not use signal boosters. Keyless entry is a great idea poorly implemented, it should have proper timings so that boosting/relaying does not work, that would at worst add about a pound to the keyfob and a few pounds to the system in the car.

facade

forgotmyname said:

Car_54 said:

Do you really understand the physics?

Not only do I understand I went a step further as anyone that comments on the subject should and tested the 'old wives tales'

of what works and what does not.

I tested the fridge, phone and car keyfobs still work. Rubber seals and a lot of plastic in the panels these days does not create
a metal to metal seal.  The same with the microwave, not a metal to metal seal on the door so a phone and car fob still work.

Tried metal biscuit tins with the same results, because it's not a continuous seal between the lid and the base the signals
still escape. The pouches work 'IF' properly sealed but many don't and the ones that do when new sometimes break
down through usage.

Not the complete list of stuff I tested but the one that worked most reliably was wrapping in kitchen foil but I do have an unknown
brand that failed for some reason. Maybe it's got a plastic coating preventing a metal to metal seal?

I know that a 'phone will keep cranking up the output power until it can get a reply from the cell tower, and depending on the carrier switch bands too (I don't see how it can receive the reply though)

My toffee tin has a push on lid where the flange overlaps the base, so any hole is a very narrow slot (I joined the lid to the base with a flexible copper wire soldered to the tin), I also tried earthing the wire that joins the lid to the base and it made no difference. (The key still works)

The microwave not working is a bit worrying, it is supposed to stop microwaves escaping!