More and more cars are now keyless with just a remote to start the vehicle. With a couple of our products such as the HitchSafe and the Window Mount Key Safe, a common question is "Will these product block the remote signal so that the vehicle can not be opened while the fob is in the safe?"
Short answer is on the HitchSafe we have experienced 100% success with blocking, with the Car Window Safe perhaps 70% success -- With the fob wrapped in a layer of aluminum foil 100% success.
How does that work? The Faraday Cage Effect.
A Faraday Cage blocks signals from escaping from inside the above two products based on the geometric shape and the material of the product. Aluminum is more effective which is why the HitchSafe (constructed of high impact aluminum) is more effective than the KeyGuard car window safe.
Other examples of the Faraday Cage:
- A microwave oven utilizes a Faraday cage, which can be partly seen covering the transparent window, to contain the electromagnetic energy within the oven and to shield the exterior from radiation.\
- Plastic bags that are impregnated with metal are used to enclose electronic toll collection devices during shipment to the customer, so that a toll charge is not registered if the delivery truck carrying the item passes through a toll booth.
- The shield of a screened cable, such as USB cables or the coaxial cable used for cable television, protects the internal conductors from external electrical noise and prevents the RF signals from leaking out.
- A booster bag (shopping bag lined with aluminium foil) acts as a Faraday cage. It is often used by shoplifters to steal RFID-tagged items
Test out the HitchSafe or the Window Mount Key Safe to make sure the Faraday Cage effect works in your situation. Wrapping the fob in aluminum foil further enhances the impact.