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Mac 911: A wild Wi-Fi ride to hunt a pesky set of problems

Glenn Fleishman | April 6, 2015
There's no technology simultaneously more useful and frustrating than Wi-Fi. Wireless local area networking shouldn't be rocket science at this point, even though it involves fiendish calculations and increasingly sophisticated physics.

There's no technology simultaneously more useful and frustrating than Wi-Fi. Wireless local area networking shouldn't be rocket science at this point, even though it involves fiendish calculations and increasingly sophisticated physics.

While setting up a Wi-Fi network has become simpler over time and networks more reliable, when a connection doesn't work, you could tear your hair out. This might explain my expanding forehead space.

I haven't yet been able to crack why some OS X users continue to have connection issues with Yosemite. In successive updates, Apple has apparently solved frequent disconnect issues for some users, but they persist.

However, in this column I walk through a mystery sent by a colleague that, in the process of working out, will provide a lot of insight for those of you troubled by the heartbreak of inconsistent conditions that ruin streaming.

Google for it

Aaron in Kansas City, a longtime email and Twitter friend, wrote in to brag about his Google Fiber throughput. No, wait, he didn't (but I can still be jealous of gigabit broadband). Rather, his Google-supplied Wi-Fi router wasn't playing nice with an array of Macs and Apple base stations. Despite having a raging torrent of bandwidth, Aaron couldn't get consistent, hiccup-free streaming, among other problems, whether he used AirPlay or Rogue Amoeba's Airfoil.

A quick bit of background. Wi-Fi works in two different frequency bands, 2.4 gigahertz (GHz) and 5 GHz. Each band is divided up into channels to allow multiple networks to operate in the same area without causing direct interference. Apple started adding support for 5 GHz networking in 2006 with the Intel processor switchover. Apple began shipping simultaneous dual-band base stations in 2008 — ones that could create two networks at once, one in each frequency range.

The 2.4 GHz band is congested, but works well through walls and over longer distances; 5 GHz can't penetrate solids as well but has relatively fewer users. Shorter distances mean less congestion, because fewer adjacent networks interfere.

Aaron has a mix of old and new Macs, his oldest being a 2006 MacBook, plus some iOS devices. All MacBooks support both frequency bands, the first generation to do so. All the troubleshooting advice I tried with Aaron would work with anyone's network. I started out with the usual:

Consider whether interference is an issue. If you're near an industrial area, some microwave sealers and other equipment can spit out noise in the 2.4 GHz band. Near a hospital or corporate campus? Their networks might overwhelm yours or, using techniques the FCC seemingly has now found invalid, may try to shut down "rogue" networks — any network that the system can't identify as its own but which has a signal that their sensors can measure.

 

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