RT-AC66R / AC66U Dropping 2.4GHz Band

[Slapdaddy]

Router info:
RT-AC66R from Best Buy.
Came pre-installed with whatever firmware ended in 354 I believe.
Now it has 3.0.0.4.374.32 RMerlin installed.
Wireless temps are steady @ 56 °C for 2.4GHz and 62 °C for 5GHz.

First some background info...

When I purchased this router, it was preloaded with the 354 firmware I believe and I was having major throughput issues - speeds fluctuated wildly. For example, when doing a speedtest, the meter would jump from 24Mbps down to 6Mbps then up to 14Mbps, etc, etc. Upload speeds were affected the same way. So in order to remedy the issue, I did a site survey and I tried changing the wireless channels and bandwidth settings in all possible combinations to no avail. (Channel 11 is basically completely empty here so I used and still use that channel mainly) I cleared the nvram, and reinstalled the firmware from Asus' website. Problem solved. Whew..

A week later, I noticed the 2.4GHz band was basically dead. Only one device was connected to the 2.4GHz band (a computer) and the rest had dropped off the network and as far as those devices were concerned, there was no 2.4GHz signal to connect to. The computer, however, remained connected, but only at 1.0Mbps, as Windows stated, but the actual speed was 0.01-0.1 Mbps when doing a speed test. So after reading online, and seeing how people opened up the configuration page for the 5GHz band and clicked "Apply" to basically reset the wireless, I did the same. And it worked. The 2.4GHz band reset and everything reconnected....until a week later, when the problem repeated. This has been occurring weekly since I've had this router...

Now to the present...

The problem repeated weekly until a few days ago, when I finally had enough. The same problem happened - 2.4GHz band dropped BUT this time, it cut off the internet connection. No devices, even connected through an ethernet cable, could reach any websites. The router was just dead. I had to power cycle it, and there it was again, working perfectly. So like I said - I had enough. I decided to clear the nvram, install RMerlin's latest build, 3.0.0.4.374.32, and clear the nvram again after install, and input all of my settings again manually instead of restoring from a file.

Now the 2.4GHz band is dropping once per day instead of once per week. Last night, when it dropped, it kicked the internet connection to the curb and I had to power cycle the router again, but even when I power cycled the router, it was still not working, so I did it again, and it started working.

This is just not acceptable. My older D-Link DIR-655 router NEVER had these issues. It was basically set and forget and had uptime of over a year once before the power went out and forced a reset. Now I'm resetting every single day?? I won't deal with this. Does anybody have any ideas? I'm only having issues on the 2.4GHz band, not the 5GHz band, but I've read of people having similar issues on both bands but not to this severity. Should I RMA it? Should I light it on fire? Help.

 

[RMerlin]

Make sure you have 2.4 GHz band set to 20 MHz. 40 Mhz is very challenging to keep stable on this overcrowded band. In addition to other routers, you also have to contend with microwave ovens, older cordless phones, Bluetooth devices, and a bunch of other cordless devices that also use the 2.4 GHz band.

 

[jlake]

Also, make sure you remove your old wireless profiles.

http://kb.linksys.com/Linksys/GetAr...less_Network_Profiles_.xml&pid=80&converted=0

http://www.cultofmac.com/143029/how-to-forget-a-wi-fi-network-on-your-ios-device-ios-tip/

 

[Slapdaddy]

Make sure you have 2.4 GHz band set to 20 MHz. 40 Mhz is very challenging to keep stable on this overcrowded band. In addition to other routers, you also have to contend with microwave ovens, older cordless phones, Bluetooth devices, and a bunch of other cordless devices that also use the 2.4 GHz band.

I do understand keeping 40MHz stable is quite the task in today's environment, but I never had a problem running @ 40MHz bandwidth on my 655. No drops ever, it just worked...flawlessly I understand that it's a different radio entirely and that interference can affect different routers differently, but a $200 router having issues that a little D-Link 655 didn't?

As for other devices, I am running a Panasonic DECT 6.0 set of cordless phones, which does have a Bluetooth radio, and I have one microwave oven. Haven't Bluetooth coexistence algorithms become pretty solid these days in detecting conflicting networks and changing the channel in order to keep connections stable? The kitchen is under the room where the router is located and it is used quite frequently. But the 2.4GHz drop occurred every week in almost a perfect pattern, so I never thought the microwave could be causing the problem. I guess moving the router's physical location would be the only way to correct that problem. But there is nothing else that I can think of that would affect the signal in this kind of way. Well, I do have an old WRT54G running as a client bridge in G-Only mode. Could this be throwing the signal off, especially if I have the router set to 40MHz? I thought b/g protection fixed that issue.

I'll reset the 2.4GHz band down to 20MHz and see how long the signal remains up...hopefully it won't drop.

Also, make sure you remove your old wireless profiles.

http://kb.linksys.com/Linksys/GetAr...less_Network_Profiles_.xml&pid=80&converted=0

http://www.cultofmac.com/143029/how-to-forget-a-wi-fi-network-on-your-ios-device-ios-tip/

I read something about this. Can using the same SSID on a new router really degrade the stability?? Since I've been having this problem, I have reset some of the profiles on the network, but I'll have to go through all of them tonight and reset them.

 

[Pericynthion]

I posted a couple of threads about this - my theory is that some low level 802.11 or WPA negotiation is slightly different on the ASUS compared to other brands (if like me you switch say out say a netgear). It's easy to prove - temporarily change the SSID and attach a single device and test. If it works then either keep using the new one, or change it back - but revisit each client and re-establish the network connection. Unfortunately the logging is not vey helpful at this level on an Asus firmware (I spotted it using the logging on an old Apple time capsule).

 

[Slapdaddy]

I posted a couple of threads about this - my theory is that some low level 802.11 or WPA negotiation is slightly different on the ASUS compared to other brands (if like me you switch say out say a netgear). It's easy to prove - temporarily change the SSID and attach a single device and test. If it works then either keep using the new one, or change it back - but revisit each client and re-establish the network connection. Unfortunately the logging is not vey helpful at this level on an Asus firmware (I spotted it using the logging on an old Apple time capsule).

That's really interesting..and it makes sense. I'll definitely try changing the SSID as well. I'm already running everything at 20MHz...it just takes so much time to troubleshoot each specific thing.

I have another question. I had been running my SSIDs in hidden mode, as I always have, but after some light reading, turned it off as it appears it may do harm than good. Could that have been causing the router to stop broadcasting on the 2.4GHz band?

 

[RMerlin]

Well, I do have an old WRT54G running as a client bridge in G-Only mode. Could this be throwing the signal off, especially if I have the router set to 40MHz? I thought b/g protection fixed that issue.

A router configured for 40 MHz will overlap no less than 5 channels at the same time. Out of 11 available channels, that doesn't leave you with much room for interference-free use, especially if you have that other router also taking 3 channels. That means that with just your own routers, you are using around 8 channels out of 11.

I think the effect might be worse if the the WRT54G is using 802.11g, but a wireless expert might want to confirm or deny that one.

 

[Pericynthion]

I have another question. I had been running my SSIDs in hidden mode, as I always have, but after some light reading, turned it off as it appears it may do harm than good. Could that have been causing the router to stop broadcasting on the 2.4GHz band?

Shouldn't have any real impact - but it does mean the clients need to be 'told' the name rather than it being visible in any network discovery. Most people will tell you its pretty pointless from a security perspective (its just as easy to find them with inssider etc), but I keep all mine hidden to stop casual bypassers (both people and any new devices) picking it up.

 

[archon810]

Just to chime in - I've had the exact same issue with 2.4GHz dropping out for months, ever since I got the AC66U. I ended up flashing Merlin and keep up with every release, but it still happens to this day. Extremely frustrating, to say the least.

Has anyone figured out definitively what this could be? Mine's set to run at 20/40MHz. Guess I'll knock it down to 20 and see what happens, but I'm incredulous. Once this problem happens, no device can connect no matter how long they try - it could sit there for days without a reconnect. If it were related to the 40MHz, would I at least expect some connections to succeed? I mean, if I reboot, it works fine for quite a while. I doubt it's caused by the 40MHz band.

 

[drabisan]

A router configured for 40 MHz will overlap no less than 5 channels at the same time. Out of 11 available channels, that doesn't leave you with much room for interference-free use, especially if you have that other router also taking 3 channels. That means that with just your own routers, you are using around 8 channels out of 11.

I think the effect might be worse if the the WRT54G is using 802.11g, but a wireless expert might want to confirm or deny that one.

Worst is when a G client attach itself to a N or AC capable router. Longer transmit window, collisions etc.
Second worst is to use a channel of a G router for a N or AC router. It will keep busy the G channel for long time, interference is a nightmare. Lots of useless work for AC router and for HT clients. The speed will never be good. What may be annoying and cause for frustrations: N/AC router may jump between 20 and 40MHz and that's bad for user experience.

40M spacing is useful and it shows its quality when it has a clear spectrum to use. When the spectrum in busy it is highly recommended to get down to 20M. In a building block with many 2.4 around it is safer to configure 20 and loose hope for high speeds in 2.4.

 

[Vidgamer]

I have the same problems as the original poster. 2.4 GHz was working for a while (I've had the RT-AC66R router for a month or so?), and then everything just went to heck. Only the 5GHz clients have been stable. 2.4GHz clients started dropping out, and then recently couldn't connect at all. From the router side, I don't see anything wrong. I have tried changing the channel which only seemed to help slightly.

I have been using 20MHz. It makes sense to me that 40MHz width might be worse, but I tried 20/40.

Like the original poster, I had a DIR-655 that worked very reliably in the past. It had developed a more mechanical/hardware problem that caused me to replace it. I hooked it up again, and it is working (for now).

In theory, one solution would be to put all of the 2.4 clients on the DIR-655 (or more likely, another new router) and leave 5GHz for the Asus, but it'd be better if I could stop throwing money away and just get the Asus to work.

Thinking of trying Merlin FW at this point. Thanks for this forum for making me aware of the option!!!

I haven't found much online from people who have this same problem, so I'm wondering why it is so selective. It's not encouraging that the OP was not fixed by using Merlin, but at this point, I don't see what else to try. If that doesn't fix it....

 

[kolyan]

how many is considered many ? My router sees about 9-10 2.4Ghz networks around. About 4 people using 6, 3 people using 1, 2-3 people on channel 11. I also dont have any wireless phones in my condo. Would you say its safe to use 40Mhz ? I am trying to maximize my Chromecast experience

 

[drabisan]

how many is considered many ? My router sees about 9-10 2.4Ghz networks around. About 4 people using 6, 3 people using 1, 2-3 people on channel 11. I also dont have any wireless phones in my condo. Would you say its safe to use 40Mhz ? I am trying to maximize my Chromecast experience

You have a very busy spectrum! Not nightmare busy but very!
No, switching to 40MHz will definitely make things worst in your case! Try channels 8 or 9 and hope for the best!

 

[Vidgamer]

Yeah, from what I've been reading, you really don't want to select 40 or even 20/40 if there is going to be interference. Good if you're in someplace remote, I guess. At the moment, I have a few routers surrounding me, plus I have a wireless telephone.

On the other hand, on the 5GHz band, I have no neighbors with routers that have this, so I'm free to suck up all the bandwidth I want. Bua-ha-ha!

Back to my 2.4 GHz problems, I changed my SSID so that nothing is connected, and I can enable one item at a time. I think what is happening is that I have a rogue device that once it gets attached to the network, it brings it all down. I'll have to re-add all of the devices one at a time and see what happens. I don't see that a device is actually pulling data from the Internet, but according to the traffic monitor, the 2.4GHz channel is full of activity. Weird.

I was hoping that Merlin would have more diagnostics to allow me to see what is happening, but I guess I have figured out the main thing I needed.

Dang, this unit runs hot, and the CPU is only running at 600, which is underclocked if I understand correctly. I look forward to being able to use the stats to keep an eye out for trouble.

 

[kolyan]

You have a very busy spectrum! Not nightmare busy but very!
No, switching to 40MHz will definitely make things worst in your case! Try channels 8 or 9 and hope for the best!

Thanks. I switched to 20 and using channel 1 for now since today I noticed that channel 6 and 11 are loaded while there is only one user using channel 1. "Auto" setting also set my router to use 6 for some reason

 

[Polen]

Not sure if this is the problem, but I too have been having 2.4GHz issues with my ac68u. The speed degrades to a trickle and even completely stops. I noticed that when I transferred files to and from the USB drive on the router the 2.4GHz wifi would break so removed the USB 3 drive from the router and now its stable.

 

[Vidgamer]

I changed the SSID and have been adding devices on one at a time, and it's been stable. In the diagnostics, in the traffic display, I am not getting the weird wireless flooding I was getting before. I think maybe a G device was just taking over the spectrum (it would display about 56Kbps, in constant use), but not actually getting to the internet. Weird, but I still haven't found what device it is. Whatever it is, it's not a commonly-used item!

Since most of my devices are "n", I may try to force that. I can always use the guest network for b/g/n.

 

[curtc]

I have this issue as well, been getting progressively worse. It started with the 5 Ghz band, so I stopped using it. Now 2.4 is requiring reboots weekly, and it has started rebooting itself randomly.

I've keep it updated with Merlin's latest. I live in the country, there are no other SSID's that I can pick up inside or out. I see a lot of very technical folks (I'm a software engineer myself) having similar issues with these newer Asus routers.

I'm at the point where I'm considering tossing this RT-AC66R for something else, but thought I'd try here for some advice. Has anyone been able to make these things stable?

 

[Vidgamer]

Well, you could try what I've done. Take everything offline by changing the SSID. Put things back one by one but not at once - see if it seems stable. I have not put everything back, and it's stable, so I think my theory of a "rogue" device is holding up.

 

[e94mli]

I had the same problem with 2.4GHz not responding after the router had been up for a while. I had the router working fine for about a year before that so it wasn't likely the config. I tried a bunch of firmwares including Merlin and regular old ones just to make sure an upgrade hadn't messed it up but nothing worked. The only difference was that with the Merlin firmware the router rebooted instead of the just the 2.4 going dead.
After a lot testing I concluded it must be a heat issue. The reason I'm pretty sure it is a heat issue is that rebooting/power cycle the router did not help but turning it off for 30 minutes to an hour would make it run again, maybe even for up to a couple of hours, before it died.
I sent my router back to Asus, after explaining the issue and my debug steps they were pretty quick to accept a return, but unfortunately it seems I got a bad replacement since the new one keeps rebooting once a day or so. Better but not exactly great...