Stingers Being Stolen

[Transmetal]

I can only speak from experience. The cheapo bags that I bought on Amazon literally stopped working after three months. The one advertised on the forum is better quality, but I couldn't say that the bag material itself is any different, because mine stopped blocking the fob after about the same time. This is using the bag continuously. As I said, mine is my wallet. I don't put other keys in it, only credit cards and the like. It came in a two-pack. I should probably just switch to the fresh one.

Oh I see what you mean, it's your actual wallet, gotcha.

 

[Snicklefritz]

Oh I see what you mean, it's your actual wallet, gotcha.

by the way, if you click on the forum ad it takes you to Amazon and you can read the comments/reviews, a lot of them are about how the faraday blocking stops working after a while. one post asserted that theirs stopped blocking after one week.

 

[Volfy]

A faraday cage is more effective at shielding EM (electromagnetic waves) if it's properly grounded. In a house, the most convenient potential drain is the electrical ground available at every outlet.

 

[Snicklefritz]

A faraday cage is more effective at shielding EM (electromagnetic waves) if it's properly grounded. In a house, the most convenient potential drain is the electrical ground available at every outlet.

are you saying that "portable" faraday bags are more of a scam than a practical shield against scanners?

 

[Volfy]

are you saying that "portable" faraday bags are more of a scam than a practical shield against scanners?

I don't have any first hand experience with any of them, so I can't say. I would hazard a guess that, if the bag's (mesh?) material is highly conductive and tightly woven, then it would probably work similarly to wrapping the key fob with aluminum foil. The effectiveness can be tested by walking up to the car and see if the unlock button responds. For that, an ungrounded faraday cage might attenuate the RF signal enough to make a difference.

That said, from the vids I see on youtube, the thieves are using hand-held high-gain directional antenna, likely powered by an RF amplifier far more powerful to retransmit the RF signal, which the car's own (much weaker) TX puts out. To safeguard against that, you need two things: distance, and more effective EM shield, with a good drain to ground.

 

[Snicklefritz]

That said, from the vids I see on youtube, the thieves are using hand-held high-gain directional antenna, likely powered by an RF amplifier far more powerful to retransmit the RF signal, which the car's own (much weaker) TX puts out. To safeguard against that, you need two things: distance, and more effective EM shield, with a good drain to ground.

I have this theory, that when the "mesh" starts to become compromised through use, a faraday bag still provides distance protection, i.e., the thief would have to get within obvious visual range in order to paint your fob in its faraday bag - in my case, inside the one like is advertised here, in my front pants pocket. This danger would only be obvious in a parking lot, with someone following me, and getting close enough to capture the signal, then relay it to a second thief who is watching vehicles to see which one lights up. If I just carried the fob exposed in my pocket or hanging from a belt/loop, the RF signal would be fully exposed, thus increasing the range from which the scanner can capture it. Is this theory of reduced range from inside a worn faraday bag legit, or am I dreaming?

 

[rpoffen]

For your house, perhaps a small grounded metal box to put the keys in.

 

[JSolo]

Someone's messing with me!!#@ Go to change the light bulb in the garage door opener, clicker stops working. ~20 min later, all works fine like nothing ever happened. Strange!

 

[Snicklefritz]

For your house, perhaps a small grounded metal box to put the keys in.

It's strange what works to block and what doesn't. I experimented with a "Brinks" strong box, put the fob in it and walked up to the car and the doors unlocked just fine. But wrapped in aluminum foil is a 100% block. So, I keep the spare fob wrapped in foil, in the Brinks box.

 

[JSolo]

^^I pulled the battery from the spare fob within days of buying the car. It sits unused in a drawer, figured no point in leaving the battery connected. I'm down to just a handful of the cr2032 batteries (which ironically the opener in the post above yours takes).

 

[Volfy]

It's strange what works to block and what doesn't. I experimented with a "Brinks" strong box, put the fob in it and walked up to the car and the doors unlocked just fine. But wrapped in aluminum foil is a 100% block. So, I keep the spare fob wrapped in foil, in the Brinks box.

Those portable safes might resemble a faraday cage, but in practice there are problems with it electrically. First, the two clam shells allow for a long continuous break in the cage, which can compromise RF shielding. That entire perimeter of the lid is coated with paint and don't make good electrical contact. You might assume the hinges provide a solid electrical contact between the two halves; they might not. For an industrial control panel, it is not considered fully bonded, unless all the metal components attached to the main body (lid, cable glands, etc.) are given a dedicated ground strap. This is done for electrical safety and RF shielding.

Same problem with those woven bags with a big old flap of an opening. This is why over-wrapping with aluminum foil is so effective.

In fact, a poorly bonded metal box might actually make things worse. Part(s) of it might act like an antenna or bounce the RF waves around whichever way, producing unpredictable and undesirable results.

 

[rpoffen]

It's strange what works to block and what doesn't. I experimented with a "Brinks" strong box, put the fob in it and walked up to the car and the doors unlocked just fine. But wrapped in aluminum foil is a 100% block. So, I keep the spare fob wrapped in foil, in the Brinks box.

Might make a difference if it was grounded, certainly there are ways to electrically ground the box.

 

[lil_lurking_stinger]

Nothing is going to stop a determined theif. From renting wreckers to tow your car, crashing into the garage or literally just holding you at gunpoint.

For this particular signal-repeater exploit. Just know no car is really safe from it. I’ve been seeing a number of Camaros and Chargers/Challenger owners getting their car stolen by this exact method. So feel safe in knowing that most thieves will target those highly-popular cars before they even look at your Stinger.

Also a faraday cage, as discussed, isn’t an optimal solution due to it possibly failing whenever and leaving you vulnerable. So unless you’re testing it every week, I would just default to the aluminum foil method. It’s both cheap & effective as a single roll is $7 and will last you an entire year and more with only this application in mind.

But no one is talking about the real solution. A kill switch.

A kill switch + aluminum/faraday cage shielding should lock down any theft attempts. The only way they can steal it at that point is holding you at gun point. By which I doubt a car is much of a worry.

 

[Thomby]

are you saying that "portable" faraday bags are more of a scam than a practical shield against scanners?

It's strange what works to block and what doesn't. I experimented with a "Brinks" strong box, put the fob in it and walked up to the car and the doors unlocked just fine. But wrapped in aluminum foil is a 100% block.

Might make a difference if it was grounded, certainly there are ways to electrically ground the box.

It's not the thickness/heaviness of the metal, or being grounded, that makes a Faraday cage effective (unless you're talking about very powerful signals). It's having a conductive material surround the object, with no/few openings larger than the wavelength you want to block.

A conductive sphere will distribute electrical charge evenly around its outer edge because electrons repel, so when you point an EM wave at the sphere, it gets dissipated around it instead of passing through. A Faraday cage approximates a sphere, for wavelengths too large to pass through the holes in the cage.

Your microwave door, for example, has a metal grid that blocks the ~10cm/4" microwaves while letting you see through it. If they were much smaller, the door edges might become an issue.

I suspect the reason inexpensive Faraday bags wear out is that they have thin metal mesh to remain light & flexible, and everyday use eventually breaks enough strands to leave gaps big enough for the signal to pass through.