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.

If the wire or mesh of the Faraday cage has gaps or holes, then it will let some frequencies through. In this way, the Faraday cage acts like a high pass filter, letting through some higher frequencies while blocking out lower frequencies. This, if anything, would undercut the claims of the WiFi guard – the 10% of the signal that is getting through is likely to be higher frequencies, which are the ones that fearmongers falsely state are dangerous.

This gets us to the core scam – there is no danger from WiFi signals. As I have discussed many times before, the EMF used in communications is non-ionizing radiation. That means, by definition, it is too weak to break chemical bonds, and therefore do things like damage DNA. This doesn’t, but itself, mean that there is zero hazard from EMF. It can still have a physical effect on tissue. But the best evidence we have so far is that this effect is limited to insignificant heating. Keep in mind, these frequencies are all lower than sunlight.

To understand this further, we need to explain the difference between hazard and risk. A shark swimming in a tank is a potential hazard, but the risk to you is zero as long as you stay out of the tank. Swimming in that tank, however, is a clear risk. So, what the research shows (to give a very quick summary) is that the hazard from EMF in the power and frequencies used for WiFi and other communications is extremely low, but we cannot prove it is zero. However, at the same time there is no evidence of any actual risk – so the amount and type of EMF that people are getting exposed to does not seem to actually increase the risk of any harmful outcome. As you might imagine, this research is complex and imperfect, and it is impossible to prove zero risk, but we can say the risk is low enough that it is probably not worth worrying about.

There is also the issue of those individuals who believe they have EMF hypersensitivity. I have discussed this before as well, and let’s just say there is no objective evidence that this condition exists. Whenever alleged hypersensitive individuals are blinded to whether or not they are being exposed to EMF, they cannot tell.

And here we have two of the layers of this scam – there is no legitimate reason that you would want to block your WiFi signal, and you cannot do so without blocking the very function of the router. We could include another layer in that the WiFi router represents a tiny amount of the total EMF to which you are exposed. So blocking it would not have a significant effect in any case.

But the other layer is – if for some reason you wanted to reduce your exposure to the EMF from your WiFi, you could just turn it off. Or, don’t use WiFi, use an ethernet hard connection for all your computers, TVs, and similar devices. For the handheld and portable devices – sorry, but there is no way to connect them without some EMF, whether it’s WiFi or 5G. Either you are connecting through your WiFi or you are connecting through your cell phone service.

In fact, it’s possible that if you are trying to use a portable device while blocking the very WiFi you are trying to connect to, you might increase your personal exposure. If your cell phone, for example, is having trouble finding a signal, it will continuously look for that signal, sending out pings and draining your battery. I’m not sure about the math here, but it seems plausible.

Further still, if you, for some reason, feel like the best compromise is to have a weak WiFi with just enough signal so that you can shop on Amazon for more pseudoscientific products from your smart phone, but not enough to cause harm, then there are simpler ways to accomplish that goal. Rather than buying a high power router and then blocking 90% of the signal, why not just get a really weak router? That would be a lot cheaper. You can also keep the router at the far end of the house, away from where you sleep or spend most of your time. To be clear, I am not recommending this, as there is no reason to think there is any health risk from your WiFi router, but if that were your goal, this is a lot simpler and cheaper way to achieve it.

In other words – no matter how you look at it, this device is entirely worthless.

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