Does the metal casing of a desktop PC interfere with the dongle of a wireless keyboard and mouse?

Question

In my home setup I have my work laptop in a docking station. Behind that is an old desktop PC, which is in a metal case. They are close because I don't really have the space to put them further apart.

Some months ago, I replaced a failed keyboard, with a new wireless keyboard and mouse. I plugged the dongle for the wireless keyboard and mouse, into the work laptop's docking station. However, I would experience frequent lockups of the mouse and keyboard. The laptop wasn't frozen, as I could hear videos going on (bad when in a Zoom call with colleagues), but the input devices weren't working. The only way I could fix it was by doing a power down of the laptop via the docking station's power button.

I went to Best Buy to talk with them about how to fix it. They said that it was the metal case of the old desktop which was causing the problem. That it was interfering with the signal to the dongle from the wireless keyboard and mouse. They recommended another wireless keyboard and mouse with a more secure connection between keyboard/mouse and dongle. So, I bought it. I've been using it for 3 weeks. It is an improvement. Before my work laptop would freeze the mouse and keyboard 6 to 8 times per day. Now it only does so 1 to 2 times a day. However, even that is a nuisance, and it can be a real problem if I'm doing something critical.

Here's the questions I have about my situation. First, it does seem like what the guy at Best Buy said was correct, that the signal from keyboard/mouse to dongle can be affected by the metal of the old desktop. (The old desktop is 5" away from the dongle. That's as far as I can get them apart.) Taking the distance between the two as a factor, how far should I get the old desktop from the dongle in the work laptop?

Second, is there some shielding I can use to stop the interference between the dongle and the old desktop's metal casing?

Answer 1

I have always had some amount of connectivity issues with wireless mice, one time associated with an improperly installed motherboard "case plate" (I/O plate) where part of the plate was making contact with the USB connector sleeve.

However, the bigger culprit is radio noise or electromagnetic interference (EMI). Most of these wireless devices live in a widely-used frequency band and so various devices in your environment often will jam the signals. I have had signal issues even with a ATX tower on the floor next to my feet.

What I do typically is I use a USB extension cable, plug the dongle into that, and place the dongle end very close to the mouse and keyboard (e.g. at the base of my monitor) in the hope that the signal will be much stronger than the noise. This has worked for me 100% of the time.

See for example this Intel white paper (pdf; Page 9) for an example of a USB3.0 specification device generating noise in the frequency band of a typical wireless mouse.

All that said, needing to power down the laptop (as opposed to re-plugging the USB dongle) to regain mouse and keyboard implicates the docking station, in my opinion.