DSL-AC68U - Wifi 2.4GHz band interference issues with USB 3.0 drive

[RobinB]

TLDR; Skip to the bottom to read the solution.

I typed up about the problem of 2.4GHz wifi constantly dropping / disconnecting that I had been experiencing with my DSL-AC68U, until I found the solution so thought I'd post it anyway as this may help someone with the same issue.

(1) Bought the router secondhand recently, reset and updated the firmware to the latest.
(2) Did manual settings using wizard.
(3) 2.4Ghz wifi was temperamental. It's very unpredictable. When the router was restarted, it worked okay for few minutes then would drops sometimes, speeds are really slow (~1.5Mbps), wouldn't load anything. Took ages to even load ASUS configuration page.
(4) 5.0Ghz wifi worked perfect. No issues, achieved top internet speed and everything
(6) I have checked the 2.4Ghz interference / noise checks. There was no congestion. I had manually changed to different channels. Still the same issue.
(7) I tried Merlin's pinned post regarding Wifi troubleshooting. Still no luck.
(7) One of the threads suggested changing "20/40Mhz" to just 20Mhz which I tried but still the issue remained.
(8) I was running an FTP server using a USB 3 drive and DDNS so I thought that might be causing issues, so I disabled both but with no luck.
(9) I hard reset it, tried doing minimal and manual configuration as per the below but with no luck:
https://www.snbforums.com/threads/n...l-and-manual-configuration.27115/#post-205573
(10) I installed the latest ASUS Merlin firmware in a hope that will sort it out but still the same issue persisted.
(11) Someone suggested to Hide the normal 2.4Ghz SSID and use the Guest 2.4Ghz SSID, that seemed to work fine. but I needed to sort out my proper 2.4GHz band and not a guest one.

Finally, I stumbled upon a thread that mentioned about an inherent design problem with Asus routers i.e. USB 3.0 interference with 2.4GHz band. So I got this solution that sorted out my wifi issues:

SOLUTION: If you have a USB 3.0 thumb drive / hard drive connected to the USB port for running a server share, go to Network Map, click on the USB 3.0 drive icon, change the mode from USB 3.0 to USB 2.0, that should fix your wifi problems. Apparently Asus routers have this problem that USB 3.0 causes interference to 2.4GHz band, so unfortunately you have to live with USB2.0 speeds for your network storage if you want a proper functioning 2.4GHz band. Troubleshooting this issue cost me a huge amount of time because I left the USB 3.0 drive plugged in the USB port even when I tried different resetting / rebooting steps so the whole thing was very unpredictable.

 

[OzarkEdge]

TLDR; Skip to the bottom to read the solution.

I typed up about the problem of 2.4GHz wifi constantly dropping / disconnecting that I had been experiencing with my DSL-AC68U, until I found the solution so thought I'd post it anyway as this may help someone with the same issue.

(1) Bought the router secondhand recently, reset and updated the firmware to the latest.
(2) Did manual settings using wizard.
(3) 2.4Ghz wifi was temperamental. It's very unpredictable. When the router was restarted, it worked okay for few minutes then would drops sometimes, speeds are really slow (~1.5Mbps), wouldn't load anything. Took ages to even load ASUS configuration page.
(4) 5.0Ghz wifi worked perfect. No issues, achieved top internet speed and everything
(6) I have checked the 2.4Ghz interference / noise checks. There was no congestion. I had manually changed to different channels. Still the same issue.
(7) I tried Merlin's pinned post regarding Wifi troubleshooting. Still no luck.
(7) One of the threads suggested changing "20/40Mhz" to just 20Mhz which I tried but still the issue remained.
(8) I was running an FTP server using a USB 3 drive and DDNS so I thought that might be causing issues, so I disabled both but with no luck.
(9) I hard reset it, tried doing minimal and manual configuration as per the below but with no luck:
https://www.snbforums.com/threads/n...l-and-manual-configuration.27115/#post-205573
(10) I installed the latest ASUS Merlin firmware in a hope that will sort it out but still the same issue persisted.
(11) Someone suggested to Hide the normal 2.4Ghz SSID and use the Guest 2.4Ghz SSID, that seemed to work fine. but I needed to sort out my proper 2.4GHz band and not a guest one.

Finally, I stumbled upon a thread that mentioned about an inherent design problem with Asus routers i.e. USB 3.0 interference with 2.4GHz band. So I got this solution that sorted out my wifi issues:

SOLUTION: If you have a USB 3.0 thumb drive / hard drive connected to the USB port for running a server share, go to Network Map, click on the USB 3.0 drive icon, change the mode from USB 3.0 to USB 2.0, that should fix your wifi problems. Apparently Asus routers have this problem that USB 3.0 causes interference to 2.4GHz band, so unfortunately you have to live with USB2.0 speeds for your network storage if you want a proper functioning 2.4GHz band. Troubleshooting this issue cost me a huge amount of time because I left the USB 3.0 drive plugged in the USB port even when I tried different resetting / rebooting steps so the whole thing was very unpredictable.

USB 3.0 speed generates EMI that can interfere with 2.4 GHz WiFi. Enabling both on a wireless router solicits interference. The user has to disable USB 3.0 if they want to use 2.4 GHz WiFi without the interference. A well-shielded USB 3.0 cable might help.

OE

 

[Chuckles67]

I've just experienced the same with Asus RT-AC66U-B1 using a USB connected SSD drive.

On 2.4GHz WiFi:
- with USB3.0 internet speedtest download is <2Mbps
- changing from USB3.0 to USB2.0 restores internet speed to expected 18Mbps

On 5G WiFi: no difference.

Using USB3.0 can affect WiFi 2.4GHz internet speed very much!

UPDATE: I was able to get USB3 working - without slowing down WiFi 2.4GHz: I'm using a new UGreen SATA drive enclosure with an old Intel 80GB SSD. With the drive at the front of the router and the USB cable coiled the internet speed on WiFi 2.4GHz drops as above. By straightening the cable and moving the drive enclosure to the rear and below the router, the WiFi 2.4GHz works properly with internet speeds at expected 18Mbps. Worth playing around with!

UPDATE 2: unfortunately the WiFi 2.4 GHz speed has dropped, especially further away from the router such as the garage or back yard, and disabling USB3.0 => USB2.0 fixed the issue. The only thing that changed was flashing from Merlin 384.17 to 384.18 (I doubt this caused the problem). I'll stick with USB2.0 now on for domestic peace