Wi-Fi Turns Off Display

I’m hoping there is a WiFi expert who can answer this.

Last week, Xfinity replaced my router, and an old problem resurfaced. My LG Ultrafine Display is going blank at random times for 5 seconds a time. In addition, software on my Mac Studio exhibits some strange delays. Anyone who uses an LG Ultrafine will know about this, because there was a massive LG recall in 2017-18 to fix a WiFi shielding problem identified by Apple engineers.

  • The previous router (Motorola) communicated on 802.11 b, g, n.

  • The new router (Arris TG1682G) adds a, ac, ax but drops b.

  • The new router (Arris TG1682G) also adds a 6GHz channel with 802.11 ax.

  • Could the display interference be caused by the a/ac/ax protocol?

  • Could the display interference be caused by the new 6GHz channel?

  • Could turning off one of these be a fix?

Doubtful. These protocols change the nature of the data moved over the 2.4 GHz and 5 GHz bands, but that shouldn’t have a significant impact with respect to interfering with other devices.

Maybe, if LG’s shielding fix didn’t block that frequency. Since I don’t know what the fix actually entails, I can’t say more.

Definitely try disabling the 6 GHz band. If that solves your problem, it’s no big loss, since you probably don’t (yet?) have any other devices that can use the 6 GHz band.

Another thing to consider is if you might be able to position the router further away from your display (or maybe the Mac or its video cable). The power levels from the antenna will be significantly lower if you can move it a few feet further away.


2 ideas for improving the RF shielding:

3M and other companies make metal foil with an adhesive back that you can use to cover all plastic surfaces of the monitor other than the vent holes.

I assume your monitor only accepts Thunderbolt 3 cable, not HDMI. That’s too bad because Belden makes great HDMI cable but not Thunderbolt 3 or USB3 video cable. You might try another top brand of Thunderbolt 3 video cable, altho I don’t know what brand to recommend.

They sell it in hardware stores for sealing HVAC ducts.

But note that if you use it on electronics, you must bond the metal to ground. Otherwise that foil may act as an antenna, making your problem worse (or reflecting the EMI to other nearby devices).

With luck, your monitor has a grounded screw somewhere, which you can use for this purpose.

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It turns out that one thing I had not considered has helped: moving the router farther from the display. I’m lucky I could do that. So far, it seems to be working.

Thank you, everybody for the suggestions.