iPhone 15 Pro DisplayPort Output (via USB-C): Severely impacted WiFi speeds

[learjet]

From time to time, I utilize the DisplayPort output on my iPhone 15 Pro through USB-C "alternate mode" to project content onto an external 4k display. When employing a USB-C-to-DisplayPort cable or different USB-C-to-HDMI adapters and cables, I observe a significant reduction in WiFi speeds, particularly within the 2.4 GHz spectrum. Upon testing with the Speedtest.net app, both upload and download speeds quickly drop to single-digit Mbps values.

I've encountered this issue with various USB-C-to-DisplayPort cables and different USB-C-to-HDMI adapters and cables. I suspect a potential hardware problem, such as insufficient shielding.

Has anyone else experienced and reproduced this issue?

 

[JPack]

Yes, many of the cheap adapters and hubs have this RF shielding issue. People typically report this when using their Mac or Windows notebook.

 

[MRxROBOT]

There's lots of reports of this online. The fix is to use a higher quality cable with proper RF shielding.

 

[learjet]

There's lots of reports of this online. The fix is to use a higher quality cable with proper RF shielding.

I‘m using a CableMatters USB-C to DisplayPort Cable. Doesn‘t get much more high quality than this. And, all my other HDMI cables and adapters, high quality branded and certified, lead to similar WiFi issues.

Additionally, I can report that WiFi 5GHz isn‘t affected by this at all.

 

[MacCheetah3]

What they said.

What Causes USB 3.0 and 2.4 GHz Interference?

USB 3.0 generates frequency noise that causes interference on the 2.4 GHz band at a distance of 3 feet or more.

www.accessagility.com

How to Avoid the USB3.0 and 2.4 GHz Devices Interference?

Explains the interference problem between USB 3.0 and 2.4 GHz Devices and provide you with the solution.

www.rshtech.com

If you're using USB 3 or Thunderbolt 3 devices with your computer, you can limit their potential to interfere with nearby wireless devices:

• Use a high-quality, shielded USB or Thunderbolt 3 cable with each device.
• Move your USB 3 or Thunderbolt 3 devices—including any USB hubs—farther away from your wireless devices.
• Avoid placing USB 3 or Thunderbolt 3 devices on top of your Mac.
• Turn off any USB 3 devices that aren't in use.

Resolve Wi-Fi and Bluetooth issues caused by wireless interference - Apple Support

Wireless interference can cause Wi-Fi and Bluetooth devices to disconnect or perform poorly, but you can take steps to reduce or overcome it.

support.apple.com