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Lee Badman
Lee Badman
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7 WiFi Killers That May Surprise You

That festive holiday decor could be slowing your WLAN performance. Learn about little known and unusual sources of wireless interference.
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If you're interested in WiFi, love Christmas decorations -- or both -- you probably noticed recent reports out of the United Kingdom that your active holiday decor may be disrupting the WiFi signals in your home or business. Whether the impact is the result of shoddy electrical design by the manufacturers of the fairy lights (as they say in the UK) or a more sinister collusion between wireless router makers and the Christmas light industry to sell more wireless hardware is certainly a question that hangs in the air.

Are ugly, light-up sweaters responsible for mobile denials of service? That one is still being investigated, but there is one clear truth that wireless experts already know regardless of the holiday light dust-up: Non WiFi products very much can make wireless life miserable.

Without diving too deep into the technology, we can boil the problems down to a couple of regulatory realities. WiFi works in the unlicensed 2.4-GHz and 5-GHz frequency ranges. There are many other devices that also leverage the fact that you can transmit in these spectrums without expensive and complicated licensing requirements.

In addition, all the wireless devices that tend to step on each other are required to tolerate interference, unless you can change their channel to a non-polluted one within their operational profiles. In other words, interference is a fact of life under the current rules. Now that you know about pretty lights with evil intentions, let's take a look at a number of other common interferers that you may not be aware of.

(Image: franckreporter/iStockphoto)

 

Lee is a Wireless Network Architect for a large private university. He has also tought classes on networking, wireless network administration, and wireless security. Lee's technical background includes 10 years in the US Air Force as an Electronic Warfare systems technician ... View Full Bio

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MarciaNWC
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MarciaNWC,
User Rank: Strategist
12/16/2015 | 5:15:59 PM
Re: Thank for Sharing
Glad you liked the list! Thanks for chiming in here.
chantrodge11
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chantrodge11,
User Rank: Apprentice
12/15/2015 | 6:31:58 AM
Thank for Sharing
Some of these could be the reason for my slow Wifi. Will have it checked. Thank you so much for sharing. Was surprised that <strong>bluetooth</strong> is included on the list.
Brian.Dean
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Brian.Dean,
User Rank: Ninja
12/8/2015 | 9:08:37 PM
Re: Aluminum and Christmas Decorations
Alarm clocks with a wireless outdoor temperature sensor can also cause interference and the worst part is that in the whole troubleshooting process, the alarm clock is the last device that one would consider as the problem. It is another instance where a spectrum analyzer can save countless hours. Installing a quick app on a phone can also provide some insight on the type of RF that occupies a location. 
MarciaNWC
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MarciaNWC,
User Rank: Strategist
12/7/2015 | 1:43:08 PM
Re: Aluminum and Christmas Decorations
Thanks for chiming in with this advice @tgawel! Very helpful. Did it take a while to figure out that the aluminum blinds in that office were the culprit?
tgawel
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tgawel,
User Rank: Apprentice
12/7/2015 | 12:45:06 PM
Aluminum and Christmas Decorations
Also watch out for Aluminum Blinds, Aluminum reflectors in light fixtures and Christmas tree decoration.

I ran into a problem on our campus with a person who had aluminum blinds in their window. The AP was right outside her door. Pull up the blinds and you had full Wi-Fi Signal. Drop the blinds and zero signal.

 Also ran into a situation with dramatically reduce Wi-FI signal in a classroom. Turns out the ceiling lighting fixture had a aluminum reflector. Moved the AP a few ceiling tiles and problem went away.

 I have an interference problem right now in a large auditorium with all the decoration and a large Christmas tree affecting not only the Wi-Fi, but also the wireless microphones and monitors.

 A spectrum analyzer help in tracking down the culprits and helps show the staff and students the reasons for the interference.

 
jerome-denis
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jerome-denis,
User Rank: Apprentice
12/4/2015 | 11:07:41 AM
Re
"but can drive you nuts when they disrupt your streaming video while coworkers are nuking their burritos" haha this is so true !

Great article thanks 
ClassC
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ClassC,
User Rank: Ninja
12/3/2015 | 9:33:45 PM
Re: cordless phones

This was a really good reference for things to look out for when troubleshooting Wi-Fi.  

Many of these I wasn't aware of and now can consider when Wi-Fi issues appear.

lbadman132
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lbadman132,
User Rank: Ninja
12/3/2015 | 9:31:09 PM
Re: cordless phones
Unfortunately, the cordless phone thing can be downright rediculous. I have studied phones that were labelled as 5.8 GHz only, and watched them change frequency to 2.4 GHz when you move them beyond a certain range away from the base. Same with 2.4 GHz phones changing to 900 MHz or even 400 MHz, with no mention of these in the data sheets. Then there are the "digital" phones that aren't- that can be heard clearly on a scanner.  Though this is an older article I wrote from a periodical no longer in print, it tells all about the phone wonkiness:

 

lhbadman.mysite.syr.edu/cordlesscune2006monitoringtimes.pdf
MarciaNWC
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MarciaNWC,
User Rank: Strategist
12/3/2015 | 3:54:31 PM
cordless phones
Thanks for this list Lee! I didn't know about the cordless phone problem. I wish I had known what to look for when I bought my cordless phone replacement a couple years ago!
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