ASUS RT-AC86U weird 5GHz wireless issue

[czaki]

Hello Everyone,

I am having a weird issue, I hope you can help in solving it. My setup is the following: a DSL-AC68VG operates in modem only mode, behind it there is an RT-AC86U (router #1) which is the AiMesh router and there is a second RT-AC86U (router #2) to extend the coverage as an AiMesh node. I have my 2.4Ghz and 5Ghz networks separated with different SSIDs.

When I checked the AiMesh router admin page, I was seeing that the link between the two APs turned to weak in the AiMesh control panel. In the past it was operating without any issues and showed strong signal for the AiMesh node. After further digging into the settings I realized that the uplink is 2.4GHz only. I have tried to disable the 2.4GHz radio in the AiMesh settings for router #2 to trigger the device to use 5Ghz only but the only thing I have achieved with this to be completely unable to connect to any of the wireless networks. The AiMesh network dropped as well so I had no other choice than to reset the both routers #1 and #2 hoping that it will solve the issue. This is where the fun began: regardless of doing a soft (using the reset button on the back) or a hard reset (using the WPS button method) and both of the radios active, router #1 was showing a seemingly operating 5GHz network, but it did not allow to connect any device to it (the 2.4GHz network worked flawlessly in parallel). I was also trying to connect router #2 with AiMesh and after 2-3% progress the connection process failed with an error message.

As an alternative solution I thought to replace router #1 with #2 to see what happens. Surprisingly, with router #2 being set up as the AiMesh router both networks were visible and OK to connect to. AiMesh setup with router #1 as a node was also completed. Still the uplink is 2.4GHz only and weak, and if I would like to get a more distant device connect to the 5GHz network (presumably using the AiMesh node as the connection point) it fails. All of the devices that were set up for the 5GHz network are connecting straightaway to the AiMesh router (router #2) leaving the AiMesh node out of the picture (router #1). I am a bit clueless as I am not using the DFS channels and the channel selection is set to Auto to eliminate any potential connection issue. Is there any other setting which would prevent me from achieving what I want?

Both devices are approximately the same old and are running the same firmware, which is the latest Merlin build (386.13_2). I am aware that these devices are EOL but I would need to make this setup working for the time being potentially without exchanging to another device. I hope there will be some way forward since it was working without issues for weeks before this phenomenon started to happen. I doubt that only the 5GHz functionality died in router #1 (or at least I hope it did not), but of course I am not ruling this one out as the potential root cause. Any idea or support would be highly appreciated, thank you very much in advance!

 

[czaki]

Interestingly, after that no devices were able to connect to the AiMesh node (router #1) I removed it from AiMesh and reset the device completely. Now I cannot make it work with AiMesh anymore with router #2 being the main one. Strange enough I am unable to join the 5GHz network of router #1 while it works without any issue with router #2. The two devices are from different regions (Europe and Asia), but still this issue is weird to me as they were working properly in the past.

The whole problem started a couple of weeks back when my Samsung TV in the living room was not able to recognize the 5GHz network despite the device (router #1) being less than 1 meter away from it, so I had to change to a wired connection. Now my other Samsung display in a different room is also unable to join the 5GHz network, regardless of which device is running it.

What am I doing wrong? It cannot be that both routers fail at the same time. There were no thunderstorms or lightning that could damage them via the electrical network or anything like that.

 

[Tech9]

RT-AC86U is a model known for multiple hardware failures including radios. Many SNB Forum members lost one or more RT-AC86Us over time. Since it's EoL now better look for replacement of both units. You'll get potentially better reliability plus extended support. If you want to stay with Asus and AiMesh look for Pro models and Asuswrt 5.0 firmware. The cheapest one is RT-AX86U Pro with similar vertical design and dimensions as RT-AC86U.

 

[Grumpy_Geoff]

The two devices are from different regions (Europe and Asia), but still this issue is weird to me as they were working properly in the past.

There will be differences in 5GHz channel availability between the European and Asian region models.
The European model likely will not have channels 149-165 which the Asian region model will have, but it will have 120-128 whereas the Asian region model may not.

 

[czaki]

RT-AC86U is a model known for multiple hardware failures including radios. Many SNB Forum members lost one or more RT-AC86Us over time. Since it's EoL now better look for replacement of both units. You'll get potentially better reliability plus extended support. If you want to stay with Asus and AiMesh look for Pro models and Asuswrt 5.0 firmware. The cheapest one is RT-AX86U Pro with similar vertical design and dimensions as RT-AC86U.

Thank you for your response. This is understood and I am aware that these are prone to fail, unfortunately I did not know before buying these cheap in the second-hand market. For the time being I would like to be sure that the radio is cooked before moving on. Is there a way to test this or get it understood from the system log?

A single RT-AX86U Pro costs almost twice as much as I have bought the two routers hence I would like to do what is possible to service the RT-AC86U before throwing it away.

 

[czaki]

There will be differences in 5GHz channel availability between the European and Asian region models.
The European model likely will not have channels 149-165 which the Asian region model will have, but it will have 120-128 whereas the Asian region model may not.

Thanks, I was reading about this, the funny thing is that it was working without any issue for weeks. Then at a blink of an eye, the problems started to happen. It is strange that the Asian version allows only to select control channels 149 and above (see screenshot below) and it does not offer to select the lower ones between 36 and 48. Is there a way to change this?

 

[Grumpy_Geoff]

It is strange that the Asian version allows only to select control channels 149 and above (see screenshot below) and it does not offer to select the lower ones between 36 and 48.

What region do you have set in Wireless - Professional?

 

[czaki]

What region do you have set in Wireless - Professional?

Well this is funny. Yesterday evening I was trying to change this and I was not able to find this option in the settings. I checked it again this morning and I was able to change it to Europe, now the proper control channels are visible.

The above did not bring any joy though, I am unable to add the other device as an AiMesh node. It seems to me that it stuck in some sort of a software loop. I have initialized router #1 and tried to set up using a wired connection and my laptop, and after passing the QIS screens it stopped working both via wireless and wired connections. After a restart I was able to log back in, now I did a full factory reset with erasing all previous data, hoping that it will do something good. I am also thinking to upload and test the new beta Merlin firmware (386.14 beta 2) to see if it improves this behavior. I would like to rule out hardware malfunction before moving to a new device.

 

[Tech9]

I would like to rule out hardware malfunction before moving to a new device.

Router locking up right after QIS is not a good sign. Changing firmware is unlikely to help.

 

[czaki]

Router locking up right after QIS is not a good sign. Changing firmware is unlikely to help.

That is what I was worried about. It does not lock up, but only the 2.4GHz network is working. I have tried with reverting back to the stock firmware, interestingly I was able to connect to the 5GHz radio after the first few tries. Unfortunately AiMesh still did not want to work, so I turned off and packed it away. I still would be interested to investigate what went wrong, is there a way to access detailed log that might show which feature is not operating properly? I might give it a few tries when I will have more time to play around with this.

For the time being I have moved the DSL-AC68VG out of modem only state and use the remaining RT-AC86U in repeater mode to extend my wireless coverage. I do not have AiMesh but the system is working at the moment, with adjusting the radio power on the modem router I was able to create a working roaming environment.

 

[Tech9]

I still would be interested to investigate what went wrong

Look at wireless settings when 5GHz radio is not working correctly. If you see Channel 0 - don't waste your time anymore.

with adjusting the radio power on the modem router I was able to create a working roaming environment.

AiMesh doesn't make the roaming any better. It's a marketing name for wired or wireless Asus routers connected together.

 

[czaki]

AiMesh doesn't make the roaming any better. It's a marketing name for wired or wireless Asus routers connected together.

Indeed it works surprisingly well, but now I have another weird phenomenon that is not always present. The devices roam without issues and I am able to access both the router and the repeater administration surfaces from anywhere in the network. Somehow after a couple of hours the internet access stops working and I can only access the IP of the RT-AC86U, but not the DSL-AC68VG. At the same time all wired devices connected to the DSL-AC68VG continue to work without any issue, so it rules out any external internet access problem. When I restart the repeater, everything is back to normal for a couple of hours with strong wireless signal, coverage and speed.

I suspect that the access gets blocked towards the router for every device that is connected to the repeater, including the repeater itself. First I thought that the AiProtection feature of the modem router does this, but turning it off did not bring any joy. Do you happen to have any idea about the above? Which feature should I turn off in the main router? Firewall is still on. The repeater has limited settings now due to the operation mode so I think I need to set something up within the main router.

 

[czaki]

Any idea regarding the intermittent internet access loss via the RT-AC86U when it is in repeater mode?

 

[OzarkEdge]

Any idea regarding the intermittent internet access loss via the RT-AC86U when it is in repeater mode?

Yeah, the AC86U power circuit and/or radio(s) are suffering hardware failure that will exhibit weird symptoms until it stops working completely. If you want a reliable network, get rid of it.

OE

 

[Tech9]

Any idea regarding the intermittent internet access loss via the RT-AC86U when it is in repeater mode?

I remember seeing this issue in both Repeater Mode and Media Bridge, on different Asus routers and different firmware. Asuswrt has unreliable features and you have to hunt the firmware that works for your needs. The latest may not be the greatest, some things get fixed, other get broken. As a cost effective solution you can purchase a popular brand/model repeaters only and get very similar results. AC-class repeaters are pretty cheap.

 

[czaki]

I remember seeing this issue in both Repeater Mode and Media Bridge, on different Asus routers and different firmware. Asuswrt has unreliable features and you have to hunt the firmware that works for your needs. The latest may not be the greatest, some things get fixed, other get broken. As a cost effective solution you can purchase a popular brand/model repeaters only and get very similar results. AC-class repeaters are pretty cheap.

Would you recommend going back to the latest Merlin firmware? I thought for repeater mode I will not need it so I loaded the latest factory one, but before getting rid or the RT-AC86Us I might give it another go.

 

[Tech9]

Repeater Mode is available in Asuswrt, exactly the same in Asuswrt-Merlin. No need to run 3rd party firmware for this purpose.

Changing firmware is unlikely to fix hardware issues. If the router doesn't work properly on Asuswrt - replace, don't waste your time.

 

[czaki]

Repeater Mode is available in Asuswrt, exactly the same in Asuswrt-Merlin. No need to run 3rd party firmware for this purpose.

Changing firmware is unlikely to fix hardware issues. If the router doesn't work properly on Asuswrt - replace, don't waste your time.

I was on holiday in the past weeks but I managed to have a look at the issue. After doing a full factory reset with initializing all settings I have tested the router and both wireless radios were visible, the channels were showing properly in the settings and the log and the signal strength was also strong. It seems to me that both RT-AC86Us are working fine but somehow, they did not want to work together and with my DSL-AC68VG. So now all is up for sale and I have moved to never, Wi-Fi 6 capable router combo where I do not experience any issues and AiMesh is also working properly.

Many thanks for your efforts in trying to help me in investigating this issue.