Can Christmas Lights Slow Down Wi-Fi Speed?

Funny. Though I suspect the intuitive reason people think it might interfere with Wifi is that light strings (and other stuff) can create a hum in your speakers, if you place the speaker wires in the wrong spot or if the wire is long enough that it's an integral multiple of local radio transmissions. (Any sound engineer who has worked a concert is familiar with this annoyance).

But Wifi signals are the wrong frequency for christmas lights to do much, since the 60Hz that AC current runs at wouldn't be detectable by Wifi antennas, usually.

What does happen is on older GSM phones and networks you can make little pops and beeps in a speaker, if you leave the phone near it and make a call. This might also be a source of the rumor.

(I suspect this might be why they used to disallow cell phone use on airplanes, because for the pilot listening to the tower that could get really annoying if 50 people are all making calls and he has to hear "pop popop bzzzz" every few seconds. But it wouldn't be a problem nowadays because the frequencies used are different IIRC, and it's all digital anyway).

Kinda OT but that Yoda thing (Xmas tree deco? Candle?) shown there is cool! :-)

Jesse, right, I didn't mention this but I assume it is the harmonics that matter, and by the time you get out to WiFi frequencies, there can't be much energy there.

Yeah, the Yoda thing just sort of showed up. I don't know where to get that one in particular, but here's something close, maybe better..

But that is a good thing, as I can feel the wiifi not affecting my brain as much with the xmas tree on! So I am going to keep the tree up all year to cut the effects of wifi radiation. ;-}

Christmas trees, however, do attract electronic devices.

My cat is not an 'electronic device'!

Don’t believe me? Put out a Christmas tree. On the morning of December 25th, there will be battered electronic devices, wrapped in shreddedfestive paper, gathered around the base of the knocked over tree. With smashed ornaments strewn about.

And a satisfied cat trying not to look guilty...

Well, LEDs run on DC, so they need a power supply. It's safe to say that all power supplies for Christmas lights are low-cost switching supplies. They probably run at a few tens to a few hundred kHz, and that fundamental is a square wave. So in fact there are harmonics out to probably hundreds of MHz.

This is a serious concern if your "wi-fi" is actually an S-band receiver that has to receive a signal from a ground station 550 km below your orbit. The good news though is that for power supplies that meet FCC regulations, it's probably unlikely that it will affect actual Wi-Fi. BTW, if there's a big lump on the wire of your Christmas lights, it's probably a ferrite core put there to make sure it does meet FCC regs.

If you have old fashioned large bulb incandescent lights with a thermal blinker bulb then it could interfere. Those old thermal lamp blinkers create a very noisy wide band RF field when they switch. I've used them to generate wide band RF noise for testing immunity to interference.

Of course it's extremely easy to diagnose the problem. If after you get your lights set up and running your WiFi is slower than normal, unplug the lights and wait a while. If the WiFi is still slow then it almost certainly wasn't the lights.
If your WiFi improves then plug the lights back in and wait, if the WiFi slows down again then the lights are definitely the cause. In that case replacing the blinked bulb may fix things.

Christmas light a problem for Wi-Fi, no. OTOH wrapping your router in bubble wrap would, in time, likely stop it from working, Routers, and most electronic devices, generates heat and bubble wrap would both prevent ventilation and is a pretty decent insulator. Given time the router overheats and shuts down to protect itself. If your router is not sophisticated enough to turn itself off it could, conceivably, get hot enough to cause a fire.

Yeah, that bubble wrap reference was strange.

Ofcom? This Ofcom? That would be a British organisation (I am intentionally using the UK spelling here) in charge of regulating such things as TV, mobile phones, and broadband. Maybe this is an issue in the UK, if they still sell the kind of Christmas lights Paul@7 mentions. But that doesn't mean there's any issue here.

I don't know about Christmas tree lights but our microwave oven will shut down our WiFi dead in its tracks. Not only that, it seems that our neighbor's microwave interferes with our WiFi too. We'll be watching Netflix and suddenly the loading circle will appear for a while. This seems to happen mostly around dinner time so we suspect it's their microwave and not just random network gridlock.

Richard@8, The 2.4GHz frequency was chosen for WiFi specifically because it was left as a wild west (almost anything goes) frequency buy the FCC and other regulators. The FCC has extra loose limits on 2.4GHz because that is the microwave oven frequency making it already swamped with interference.

Eric@10, I hadn't noticed before but reading up I see the information did originate from the UK regulator Ofcom. The original source is a post they made about a free WiFi testing app they've made available so that UK consumers can check and improve their systems. In the original article they talk about microwave ovens, fairy lights (incandescent lamps with blinkers) and other devices. Since they appear to be the FCC equivalent I'd bet dollars to donuts that they have actually measured the problem from fairy lights.

"Everything is kind of floating in the air," Brad Cimaglio of Skyway Techs said.

I can't help but wonder if Brad himself was "kind of floating" when he said this...

But, more seriously, it's clear why Wi-fi slows down when the Christmas lights come on: Everyone in town is home and streaming holiday specials on Netflicks.