Bach Seat

A new holiday tradition is to spread FUD about how your Christmas lights can interfere with your Wi-Fi signal. This year’s holiday Wi-Fi FUD spreader is the UK communications regulator Ofcom. Ofcom hinted that “Fairy Lights” may slow down your 2.4 GHz Wi-Fi signal and everyone went crazy.

The theoretical science says it does. C|Net explains that Wi-Fi uses radio waves. Christmas lights emit a very weak electromagnetic field. So theoretically, they can interfere with the radio waves being transmitted from your Wi-Fi router. The more lights, the stronger the electromagnetic field. Also, the closer the lights are to the router, the more it may interfere with the Wi-Fi.

The truth about holiday light interfere

Communications technology consultant Stuart Lipoff, told C|Net how you’re affected really comes down to what type of Christmas lights you use. The older technology that was used to make the lights blink can indeed cause radio interference. The interference could happen if the holiday lights were arranged in series with each other. The total number of lamps in the string could be such that the combined voltage of all of them was equal to the 110 volts in a typical U.S. home.

However modern Christmas tree lights are based on solid-state LEDs. They often use an external electronic flashing controller and do not create radio noise. However, there are some LEDs that have an extra blink-controlled chip right inside the LED bulb. It turns out that these devices also create significant radio interference. The Wi-Fi interference occurs as this internal controller cycles the LED chip from on to off. The reason is somewhat analogous to the spark problem in incandescent blinker bulbs. When the LED is between fully on and fully off it can show negative resistance that causes it to creates radio energy.

You can simulate this by taking an AM radio. Tune the radio to a frequency, not in use in your area, and switching something on and off rapidly a few times. You should hear a staticky sound. The same thing can be heard during a lightning storm.

The real Wi-Fi killers

Alina Bradford at C|Net tested the theory and found there was a slight variance, be it ever so slight. She says “the variance isn’t a big deal.”

• PC World says the real Wi-Fi killers are households items that are on 365 days. These will disrupt your Wi-Fi a lot more than your Christmas lights. Microwaves are the worst of the lot, as it’s basically a metal box that when turned on uses high-powered microwaves at around 2.4 GHz (the same frequency as Wi-Fi). This creates a black hole around it for Wi-Fi signals.
  • Other culprits include ovens, freezers, fridges, washing machines, dishwashers… you name it. If it’s metal and has liquid-filled pipes, it’s going to kill your Wi-Fi signal according to Panda security.
  • Cordless phones are also problematic. They’re often more of an issue because you’re more likely to have a portable phone on your desk than a microwave.
  • Televisions and speakers are basically just electromagnets and will hurt Wi-Fi performance when placed directly near a router.
  • Your neighbor’s router. Depending on how close your router is to someone else’s, there can be a direct effect on its performance. This might prove to be even more problematic if you live in an apartment. In an apartment, you could be exposed to different signals from all sides. This means that the more interference that there is, the more your router ups it’s broadcasting, This causes your neighbor’s router to do the same… which just perpetuates the problem.
  • Water pipes can also cause interference because water absorbs radio waves.
  • Walls don’t generate electromagnetic fields, but they do weaken Wi-Fi signals that pass through (up to 25 dB’s can be lost).
  • Humans – Yes, you too are a problem! We, humans, are 55% – 60% water, which makes us a fantastic absorber of Wi-Fi.

Things to do improve your Wi-Fi

Panda Security also suggests a few things you can do to improve your Wi-Fi.

• Open your doors – Closed doors could effectively block or degrade wireless signals.
• Adjust your Wi-Fi channel – The typical default is channel 6, your router may do this automatically. If you change your Wi-Fi channel you may find that there is less interference from other routers near to you. Any two channels separated by five or more do not overlap.
• Change your Wi-Fi Frequency The most common Wi-Fi frequency is 2.4GHz.  2.4GHz is also the most polluted. Try using 5.0 GHz. Like changing your Wi-Fi Channel your router may do this automatically. If you change your Wi-Fi frequency you may find that there is less interference from other routers near to you. You will need to check your devices to see if they support 5.0 GHz Wi-Fi, some older devices, like Apple iPhone 4’s do not.
• Place your router in the center of your home. A router transmits the signal in all directions, so it makes sense to have it at the center of the home. Unfortunately, this isn’t always possible due to the cables that come with it.
• Check your cables – In general, a shorter and higher quality cable will mean a faster connection speed. It is better to use Ethernet cables from your modem to a separate router than run long phone cables.
• Invest in a new router – There’s no need to break the bank on a new, fancy router. However, some of the newer Wi-Fi routers on the market offer a notable boost in signal and speed.
• Turn your house into a Faraday cage. Build a Faraday cage to eliminate all outside sources of electromagnetic pollution. But would also mean no telephone or FM connections.

Of course, you should also take precautions to ensure that your Wi-Fi connection is secure by putting a strong password on your router and use a modern security setting like WPA2-PSK (AES).

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedIn, Facebook, and Twitter. Email the Bach Seat here.