RT-AC87U 2.4Ghz problem

[TLight]

OK this one has me stumped. Not that I'm an expert by any stretch... I must be missing something.

Situation: I have a one story house built across 2 lots. As such I have a router at one end and an AP at the other. For years I had a Linksys (forgot the model) at each point, probably even a Netgear at some point. Back then it was 2.4GHz and I used the same SSID and even matching channels on both devices. I could walk from one end of the house to another streaming a video and have no interruption. Not sure if this was the correct configuration, but it worked without problems for years.

Fast forward about a year ago and my main router went out so I replaced with an Asus RT-AC87U that I had flashed with Merlin. All still working well. Then my Linksys AP went out some time after that so I replaced with another RT-87U I had and it was flashed with Merlin. The 5 GHz access at both ends of the house worked well, but the 2.4Ghz on the AP end of the house started failing. Some devices I have that are 2.4 only would not connect. Some times could not find the Wifi, sometimes would but I would get a message that the password was wrong, even though I know it is not. The 2.4GHz on the router side of the house works perfectly.

So, I poked around to learn a little more and found that I should use different SSID's to prevent overlap and so I would be always on the strongest signal. Did it. Still have the problem. Then I used a Wifi analyzer to see where the traffic in my area was and put the two devices on different channels with the least traffic. Still have the problem. 1 out of 10 tries I can connect. But then it will not connect the next time. My iPhone will give me a "password incorrect" and my Fitbit Aria 2 scale just refuses to either see the AP or won't connect.

At this point I am thinking I have a bad 2.4Ghz radio in the AP. So, I happen to have a 3rd RT-AC87U flashed with Merlin (all 3 of these came from an installation I shut down if you're wondering why I had 3 identical units sitting on the shelf) so did a factory reset and configured it as the AP. Guess what? It is acting exactly the same. As I say, I am baffled.

Here's the current setup:

Router:
RT-AC87U Merlin 384.13.2
2.4GHz SSID = LIGHTFOOTWN-2G
Wireless mode = Auto
Channel bandwidth = 20 MHz
Control Channel = 11
WPA2-Personal, AES

AP:
RT-AC87U Merlin 384.13.8
2.4GHz SSID = LIGHTFOOTWN2-2G
Wireless mode = Auto
Channel bandwidth = 20 MHz
Control Channel = 1
WPA2-Personal, AES

If anyone can give me some pointers it would be greatly appreciated. Anyone had this sort of issue? Many thanks in advance for any help you can lend...

 

[K-2SO]

Same SSID is not your problem.
I run 2 x RT-N12D1 N300 routers as access points in my cottage. Same SSID on both for years, no trouble.

 

[markus987]

Sounds like a bug in the wireless driver or firmware. I would try a factory reset and update to the latest asus firmware. Recently asus publised an update for the RT-AC87U model.

 

[joegreat]

In my (very similar) setup, I do not have any issues for years with my two AC87U's WLAN setup (see footer)!

As most of my client devices run on 5G WLAN, I lost a bit track on 2.4G connectivity issues...

But, I recall that it could help if you remove the profiles on the CLIENT devices and reconnect/re-enter the details to get a new profile.

On the other hand I hand some troubles in the past with very busy 2.4G channels: So, I ended up to scan the networks with a smartphone (using app 'Wifi Analyzer') to find out the channels that are least busy/least level of signals and use them directly (not Auto).

Of course a reset of the router to factory defaults and reconfigure it manually, could also be a solution...

 

[TLight]

So far I have:

Factory reset and manually reconfigured the AP router (running latest Merlin firmware) - no fix
REPLACED hardware with same RT-AC87U, installed latest Merlin, factory reset - no fix
Rolled back to Merlin 354.4_2, factory reset - no fix
Flashed with latest ASUS stock firmware, factory reset - no fix

Given that I have replaced BOTH the hardware and the firmware (ASUS and Merlin), and that I am experiencing the exact same problem, it is appearing that I am not having a radio or firmware (or driver) problem. I am no leaning toward having a problem-causing client. RMerlin has warned of this on numerous occasions on this forum I know.

I THINK I only have a few clients on that end of the house that is using the 2.4 GHz AP. (Keep in mind the router in the other end of the house functions perfectly with many 5GHz and 2.4GHz devices on it, as it always has running many different versions of Merlin, currently the 384.13_2) I say I THINK because when I look at the client listing on either device and all are listed as LAN devices, whether on 5GHz or 2.4GHz or LAN. Seems the firmware doesn't do a good job of differentiating. I have seen it work in the past so will need to poke around and see if this is a known issue. Any clues how I can see which devices are on each radio of each router/AP?

In the AP end of the house I believe all I have is my iPhone 6 (which I connect to 2.4GHz to test only), Kindle Paperwhite ( only periodically) and a Fitbit Aria2 scale. The Aria2 connection issue is the first problem I had that started me down on this adventure. There could be other IoT devices but I don't think so as those are normall

Anyone have experience chasing down problem-causing 2.4GHz clients?

 

[ColinTaylor]

Any clues how I can see which devices are on each radio of each router/AP?

Log on the router/AP and look at the System Log > Wireless Log.

 

[seth_space]

as i said on the other thread..
Just for you to try.
disable the roaming assistant on all channels.. it solved several very strange 2,4 problems ( including wrong password, but that may be a coincidence) .
You will find it at: wireless and then Professional.
YMMV

 

[TLight]

I think I found the solution. At least it has been working the past hour and I am able to connect/disconnect consistently. To accomplish this I MANUALLY configured my access point as an access point, instead of using the Access Point mode. (Put in Router Mode and disabled WAN, NAT, DHCP, and moved the connection to my network from the WAN port to one of the switch ports.) Basically did it the way we used to before the manufacturers added the easier "AP Mode" configuration. This was my last ditch effort as nothing else worked and it occurred to me that the 2.4GHz on my main router (same model), as mentioned above, has always worked flawlessly throughout this ordeal.

If this ends up being the solution (ie keeps working consistently) I am not sure of the reason, unless the 2.4GHz driver works differently in AP Mode as compared to Router Mode. Doesn't make sense that it would, but I can't argue with the results to this point. Perhaps someone out there with more knowledge could provide a rationale and maybe uncover a bug. My AP router is still running the stock ASUS firmware (as opposed to the previous Merlin which is still running on my main router). At some point I may flash Merlin on the AP router, do the manual configuration for AP mode, and see if I get the same results. But for now, things are working and I don't need any of the extra Merlin functionality so I am going to enjoy things finally working.

 

[K-2SO]

I think I found the solution.

Your solution reminds me of this thread:
https://www.snbforums.com/threads/rt-ax92u-5ghz-2-slow-solved.63832/
How to fix the WiFi by enabling... QoS. Only in Asuswrt.

 

[CARBONX2]

I have had similar issues on my RT-AC88U, tried the usual reccomendations with no improvement. My main problem issue has been with my Firestick buffering and/or losing the WiFi connection. I finally stumbled across an article that referenced the limited channels a Firestick can use, 36-48 and 149-165 on 5Ghz. My Firestick couldn't even see the 5GHz SSID lately. I logged onto my router and found that Auto-Channel was selected for 2.4GHz and 5GHz. They were on channels and 11(2.4) and 100(5). I changed to manual channel selection with settings 1(2.4) and 36(5). The Firestick can see the 5GHz and is operating the fastest ever on various streaming services and is stable. Is it possible that there are more devices that can't use such a wide range as what Asus operate on?