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Shielding on updated LG UltraFine 5K Thunderbolt 3 displays fixes RF interference, crashes

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The shielding applied to LG's UltraFine 5K display is effective in eliminating the radio frequency interference problem induced by Wi-Fi routers, as well as other high-power transmitters like cellular towers "blocking" the same frequency, according to AppleInsider examinations.

"What we believe we're seeing with some reports is similar to 'blocking' of Wi-Fi gear due to proximity of a cell tower, or other strong transmitter," our test lead noted. "Where a router may not function, or be hampered by the cell tower nearby, the proximity [of the tower] is basically mimicking the effect of a too-close router on the LG."

AppleInsider testers got ahold of the LG UltraFine 5K display with additional shielding on Monday, and moved the shielding installed by LG on the new unit to a problematic monitor identified last week. Following installation, the connection problems were rectified, even when exposed to a stronger signal on the troublesome wavelengths.

"We used a 802.11ac router to induce the problems with the two test units, as well as a calibrated source of RF simulating a nearby cell tower," our testers reported. "After we moved the shielding to the afflicted monitors identified last week, we were unable to reproduce the connection problems previously seen."

LG has urged customers that are afflicted by the disconnect problem even after moving Wi-Fi gear 6.6 feet away from the display to contact LG service for assistance. However, the process for repair or replacement of a troublesome monitor currently in-use is still not yet clear and will be dealt with on a case-by-case basis.

"Talk to LG if you've got a problem," we were told by our test lead. "This isn't going to be fixed with a firmware update."

The LG UltraFine 5K Display is considered a replacement for Apple's discontinued Thunderbolt Display, offering a 5,120-by-2,880 resolution, a P3 wide color gamut, and the ability to charge a MacBook Pro using the same Thunderbolt 3 cable used for video and data transfer. The monitor is on sale from Apple directly for $974, a discount of 25 percent from the usual $1,299.95 price.



20 Comments

emig647 20 Years · 2446 comments

Mistakes happen during development, glad they are standing behind their monitors here and making it right. I've had a lot of good luck with LG products in the last few years.

kkerst 19 Years · 330 comments

Makes you wonder how stringent the FCC testing was. It's part of the compliance testing to subject the DUT to external RF interference.

Hodar0 7 Years · 6 comments

kkerst said:
Makes you wonder how stringent the FCC testing was. It's part of the compliance testing to subject the DUT to external RF interference.

I would think that the external RF would be in the 2.4 GHz and lower frequency bands, whereas the newer WiFi bands are using 5 GHz - and not too many other devices are in the 5 GHz band range.  The FCC just doesn't seem to upgrade the specs all the quickly, at least when I worked in that field.

volcan 10 Years · 1799 comments

For consumer electronics which have the lowest priority, the FCC usually states that the device must accept all electronic interference. In other words if your device is affected by interference "tough sh*t", it is up to you do something about it. It is not the FCC's problem. On the other hand your consumer device is not allowed to interfere with any higher priority system such as police, first responders, military, public broadcasting, aeronautics, etc.

Mike Wuerthele 8 Years · 6906 comments

Also, to be clear the disconnect problems don't exist in every environment, or with every unit.