Thursday, September 14, 2017

Radio Frequency Interference : USB3.0 and 2.4GHz wireless devices

There's quite a long time I didn't post anything out there. It's time to start again with a very quick and dirty post!
I recently bought a USB3.0 Hub and plugged my Logitech Unifying receiver in it, everything was going well, until I plugged a USB3.0 SSD in it too.

Let's find why!

US3.0 type C to 3xUSB3.0 type 1 + 10/100MB/s ethernet

The considered USB HUB is the following : a US3.0 type C to 3xUSB3.0 type 1 + 10/100MB/s ethernet Hub, sold by Lention.
NB: As you can see the USB cable is pinched by the aluminium casing, but this shouldn't affect performances.

The Issue
USB3 doesn't like 2.4GHz

If my Logitech Unifying dongle is plugged in the Hub, and files are transferred from an external USB3 drive, then the mouse is behaving erratically.

if it is plugged directly in a spare USB3 port on the laptop and that the Hub is at a fair distance, everything is ok.

Using a wireless device near a USB3 hub isn't a great idea, Intel explained why and how to mitigate that issue in 2012.

Radio Frequency Interference
a noise story

This Intel white paper explains why better than I ever will.
In short, the USB3.0 device emits radio frequencies in the 2.4GHz range and interfere with wireless device by increasing noise level, which at a certain point can mess up with throughput and even break the link.
  • either the brand that makes the USB3 device shields it properly,
  • or the user needs not to put a wireless antenna (WiFi, Bluetooth or any 2.4GHz wireless) near the USB3 device...
  • or, the user can wrap the device with metallic tape as Intel demonstrated in the white paper

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