Dec 04 2020
A Faraday Cage For Your WiFi
It can be amusing when there are multiple layers of fraud in a single scam, but it’s still a scam. With the holiday shopping season upon us, there are lots of products out there exploiting fear, pseudoscience, and scientific ignorance. The “Large WiFi Router Guard” now available from Amazon is a great example. Let’s unpack how silly this product is.
The seller claims that the router guard, “Blocks about 90% of the EMF large WiFi routers emit including the new 5G.” I’ll get to why some people think they should do this below, but first – let’s consider how nonsensical this very idea is. The entire point of a WiFi router is to take your internet signal and then broadcast it using electromagnetic frequencies in a radius that covers your home or office, typically 50-100 feet. If you need to cover a larger area you can use a repeater, which will pick up the signal and then boost it to extend the range. You can also use a mesh WiFi system which uses multiple devices to give larger and more consistent coverage.
The obvious problem with a WiFi router blocker is that you are blocking the essential function of the router – it can’t work if you are blocking the very signal it is designed to release. The product listing says that it can do this, “without affecting router network speed and performance,” which is impossible. I guess technically you can say that the router is still working, and you have not affected it directly, but you have effectively blocked its speed and performance outside the cage. If you are blocking 90% of the signal, you are blocking 90% of the performance.
As an aside, this product is essentially a small Faraday cage. In that respect, it does actual work in that it will block EMF. A Faraday cage is essentially an enclosure of continuous conducting material. Electrical fields will essentially distribute themselves around this outside conducting material, and those fields will tend to cancel out within cage. So if you are inside a perfect Faraday cage, you are protected from even intense electrical activity happening outside the cage. You can even touch the inside of the cage safely.
This is why, by the way, if you are in your car during a bad electrical storm, or when there is a downed power line nearby – stay in your car. It will act to some degree like a Faraday cage an can protect you.