Anybody ever tried to make a Faraday pouch?

[HenriettaMaria]

The FB page for my mother's area has a recent post from the local police force recommending keyless car fobs be kept in Faraday pouches to prevent car thieves from reading the signal and spoofing your car.  The distance between car and fob needs to be more than 10 - 15 metres to prevent this and not many of us have houses that big.

My question is, how hard can it be to make a Faraday pouch given the correct type of screening fabric?  I've had a look online but it seems that wireless communications is a subject surrounded by a thick web of consipiracy theory and associated woo (Faraday smocks for expectant mothers, anyone?). 

Has anyone tried to make a pouch and, if so, what fabric did you use for the screen (any old scraps will do for the outer fabric/lining) and did it work? 

[Lachica]

@HenriettaMaria I was going to, several years ago, and researched the fabric, which was very expensive & difficult to get hold of. I bought key pouches instead. They worked ok for a few months but I think the fabric degraded, until the car could be unlocked while the keys were in the pouch, indoors with the front door closed. Since then, we put the keys in the microwave overnight. It is, of course, completely screened. I believe a thick lead box is the only way to fully protect against thieves with amplifier devices. (Since our Skoda is now 4 years old I don't think it'll be high on the thieves' list though)

[Ouryve]

Ours has keys that can be deactivated when not in use, which is a feature for a lot of newer cars.


Any tightly closing metal tin eg a biscuit tin will do the job better than a degraded pouch. Those are best when you're out and about eg in a shop or cafe not far from your car

[Diane]

I've got a faraday box, my keys live in there unless i'm going out.

Can you use aluminum foil as a Faraday bag?
How many layers of foil to block RFID?
With a single slice of foil ~18"x12" held in front of the sensor, the badge is read at ~1" (a noticeable reduction in signal). With the foil folded in half and the badge in the fold so that it forms a single layer on both sides of the card, it was effective (could not read the badge).

[Gernella]

We took the easy way out and went on Amazon @HenriettaMaria much easier for lazy me who doesn't like to waste too much time on things I can't wear.  The spare keys were in the front downstairs bedroom so that would have been at risk if not covered up.