Do Christmas lights really disrupt Wi-Fi or is that another bit of Internet exaggeration?

To commemorate the release of its free Wi-Fi signal strength mapping app called “Wi-Fi Checker,” the UK-based independent telephone regulator Ofcom stated that Christmas lights may be deteriorating wireless signal strength. Media outlets seized the story within hours, sensationalized it, and essentially advertised Ofcom’s app free of charge. What we’re here to answer is whether or not this statement is true, and if so, to what extent.

As many of you are EE’s, you’ll already know the answer to the question, but to those who are not, or are unable to explain technical knowledge in simplified terms, a bit of laymen’s language may be appreciated. In short, anything that contains metal can interfere with a Wi-Fi signal.

Recall that wireless networks, like mobile phones, AM and RF radios, television, and lighting, function as a result electromagnetic waves traveling through air. These waves are formed when electric energy travels through a piece of metal (the antenna) and radiates outward in waves. Depending on the technology, the transmitted wireless signal will vibrate at a different frequency (measured in hertz) and occupy a different spectrum, or a wide range of frequencies.

Wi-Fi signals are usually transmitted across the 2.4 Gigahertz microwave radio band of the electromagnetic spectrum, meaning, they oscillate 2,400,000,000 times per second, whereas FM radio signals vibrate around 100 million times a second. Because the Wi-Fi signal vibrates significantly faster than the FM radio waves, its waves are shorter and require greater power to travel the same distance, making it unfeasible for long distance data transmission. But for short-range transmissions of say 50-100 meters or so, Wi-Fi transceivers are the perfect balance of cost and capability. As a result, Wi-Fi transceivers (routers) are built specifically for short range transmissions and are thus substantially less powerful than public FM radio transmitters.

For this reason, where we place the router has a huge impact on its performance. Household appliances, cordless phones, baby monitors, microwaves, other people’s wireless networks, or anything operating across the same bandwidth can all cause Wi-Fi signal interference as the low-power, high-frequency signal struggles to penetrate the obstruction. But so can metal objects like steel girders, metal desks and filing cabinets, metal shelving, pipes. Technically, anything metallic can potentially cause signal obstruction, including the unshielded wiring used in the majority of incandescent Christmas lights.

So yes, Christmas lights can deteriorate Wi-Fi signals; but the question is, how much lighting do you actually need? A ton of it. Basically, enough to create a mini-solar flare.

Source: Commotionwireless, Gizmodo, and OfCom