Tuesday, March 10, 2020

USB 3.0/3.1 ruins Wi-Fi connectivity

Have you ever had a webcast or video conference to attend and then the very moment you need your internet to work smoothly, it performs like elves are hanging tinfoil ornaments on your Wifi router? Perhaps you, like me, are hooking in keyboards and docking stations via the USB ports, and doing so could be ruining your internet connectivity!  And not by a little, but a LOT.

USB 3.0/3.1 Hubs

Honestly, USB 3.0 hubs should come giant warning labels.  Many USB devices you've been buying have some fine print that mentions "may reduce performance of Wifi."  For the last decade (since the time I got my first USB 3.0 hub) I've been having strange wifi performance which then causes phone calls to my network provider.  So for years I've been barking at the wrong people, because it turns out, USB 3.0/3.1 hubs cause interference that interfere with 2.4 GHZ wifi!

Let me break it down for you with a Behavior Driven Development scenario:
Given laptop And usb 3.0 hub
When using Wifi over 2.4GHZ
Then internet performance is greatly reduced (reduction by 20% - 100%)

Check out these before and after photos done on a late 2019 Mac Book Pro and pay attention to the speed difference from when the blue cable is plugged in and when it is not (the cable leads to my 3.0 USB hub which sits about a foot away from my laptop):
USB 3.0 hub disconnected
USB hub connected
I've replicated the problem every other laptop I've in the house and the problem is completely reproducible.  The amount of reduction varies between 20%-100% (100% mean no data moves from or to the laptop).  USB 3.0/3.1 devices work fine when directly connected to my laptop. The problem happens when a hub is added.

Solution: Turn off the 2.4GHZ channel on your Wifi

Most people have their WIFI access points sending BOTH 2.4GHZ and 5GHZ. 2.4GHZ Wifi has a longer range at a slower maximum speed.  5GHZ Wifi has over double the speed but degrades over range faster than 2.4GHZ.  This means that most people who buy Wifi routers, let the routers use both channels (2.4 and 5 GHZ) in which case their laptop will shift between the two channels as needed.

But this is a bad idea when using 3.0 or 3.1 USB devices.

Configuring your Wifi router to turn off the 2.4GHZ radio solves the problem with the laptop.  But if you're like me, you've a few things like printers, Xbox 360, or home automation that only connect on 2.4ghz.  So now what?

Solution 2: Differentiation 2.4 and 5 GHZ with different SIDs

Go back to your Wifi router and rename the SSID for the 2.4 GHZ channel to ... 2.4, and don't tell your laptop about that other SSID.  Then you're laptop stays off of 2.4GHZ and your older devices can use the 2.4GHZ channel.

Solution 3: Use a Wired Internet Connection

I've not tested this, but I expect that a hardwire connection into the laptop will solve the problem whether or not a hub is plugged in, as long as your laptop doesn't suddenly decide to grab Wifi.

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