WiFi: How Does It Work? And Is It Dangerous?

WiFi: How Does It Work? And Is It Dangerous?

You use it to chat with friends and family. You use it to watch TV. You look for jobs with it. You share photographs and updates with it. You even search for it when you’re out and about. In fact, you’re so familiar with WiFi that you probably barely consider it anymore.

But don’t let familiarity get in the way of seeing how amazing WiFi really is. Think about it. Using WiFi, you can send information from one electronic device to another through the air – the air! If that doesn’t blow your mind, I don’t know what will. So how does WiFi work?

How Does WiFi Work?

Believe it or not, WiFi uses a relatively old technology – radio waves. Radio waves are a type of electromagnetic radiation in the electromagnetic spectrum longer than infrared. The frequency of a radio wave can be as low as 30 kilohertz or as high as 300 gigahertz.

The distance between the crest of a WiFi wave is about three to five inches. A crest is translated as a “1” by a computer and trough is translated as a “0”. It is these ones and zeros which transfer information. In fact, chains of ones and zeros convey all the information we need to enjoy the internet.

For example, when streaming a film, the ones and zeros carry instructions telling your device which colour each pixel needs to display and when. Your device’s pixels then light up in this specific pattern – which you see as people, trees, sky, cars, explosions and so on.

The waves also carry instructions telling your speakers how, and when, they should vibrate. And it is these vibrations that you recognise as a piece of dialogue or a soundtrack.

This may sound like a lot of information for a wave to transfer. And it is. In fact, a film can range from around 1GB to 5GB. Streaming large amounts of data such as this is made possible because WiFi waves move at speeds of up to 500 billion cycles per second!

Let’s put that into perspective. Imagine you’re standing on a beach, watching the waves come in. You notice that one second passes between each crest. That means the wave frequency is 1 hertz – one cycle per second.

Since WiFi waves move at up to 500 gigahertz, or 500 billion cycles per second, with just those ones and zeros, they are able to transfer huge amounts of information very, very quickly.

Is WiFi Dangerous?

But wait. Aren’t radio waves like microwaves? And can’t microwaves cook food? Is WiFi dangerous?

Technically, microwaves (with frequencies between 300 megahertz and 300 gigahertz) are a type of radio wave (which, remember, have frequencies between 30 kilohertz and 300 gigahertz). Your home microwave uses frequencies of 2.450 gigahertz to heat up your food. But there’s a reason we’re not all cooking.

Firstly, the intensity of a WiFi Signal is around 100,000 times lower than a microwave. Microwaves are highly targeted, and operate at high voltages over short distances. Your WiFi router, on the other hand, operates at a low voltage, broadcasts in all directions and is used over a relatively long distance.

Secondly, radio waves are a type of non-ionising radiation. Ionising radiation can break molecules down into smaller fragments (called ions). This is why ionising radiation – such as ultraviolent rays, X-rays and gamma rays – is dangerous. But, since radio waves do not carry enough energy to fragment molecules into ions, they present very little danger.

The World Health Organisation, which has looked extensively into the health risks of WiFi, states:

“In the area of biological effects and medical applications of non-ionizing radiation approximately 25,000 articles have been published over the past 30 years. Despite the feeling of some people that more research needs to be done, scientific knowledge in this area is now more extensive than for most chemicals. Based on a recent in-depth review of the scientific literature, the WHO concluded that current evidence does not confirm the existence of any health consequences from exposure to low-level electromagnetic fields.”

How to Secure Your Router

A more pressing danger is the possibility that someone is using your WiFi without permission. This could slow down your connection and increase the amount you have to pay. To keep your router secure:

  • Secure your network with a Pre-Shared Key (PSK). A PSK us a security mechanism used to authenticate and validate users on a WiFi connection.
  • Pick a non-trivial password. Choosing something that’s easy to guess puts you at risk. Use a mixture of upper- and lower-case letters, as well as digits and symbols.
  • Set up and Access Control List (ACL). An ACL lists specific devices that are allowed to connect to your network. For each device, you will have to specify a MAC address. These are written on the bottom of laptops and round the back of desktops.