2.4ghz network issue

[stook1]

I have an RT-N66U running the stock Asus firmware. I have the router setup as an access point with both 2.4ghz and 5ghz bands available. I've increased the 2.4ghz radio transmission to 200.

I've found that my network transfer speeds on the 5ghz band are roughly 10x as fast vs. 2.4ghz, even from distances that near the limits of the 5ghz band (ie. on different floor/opposite side of the house). I live in a suburban area - there are some other networks that neighbors are operating but the 2.4ghz band doesn't seem crowded really (I can see maybe 3 other networks and there is minimal, if any, channel overlap with mine on inSSIDer).

At first I thought that the issue was a defective router and so I purchased a 2nd RT-N66U and replicated the same performance issues on the 2.4ghz band. I'm assuming that the issue is interference of some kind, although I am still pretty surprised that the issue is this extreme. Just as an example, since I forget the internal network transfer rates off hand, I am getting something like 30 megabits/s download performance on 5ghz from very far away from the router, whereas from the same location on 2.4ghz I get in the range of 2-3megabits/s.

Does performance degradation this extreme seem consistent with some kind of interference, ie from some other device in my home, or is it more likely that I have managed to get two dud routers?

 

[L&LD]

Stock Asus firmware is not descriptive.

The 5GHz band has much less interference than the 2.4GHz band, is this what you're seeing?

What device(s) are you using to do your tests with?

A newer laptop with the latest drivers for the wifi card and that is preferably plugged in and on the Performance power profile is the best device to be testing this with.

 

[abailey]

Yes it is possible to get that much interference. Especially if you are trying to use a channel width greater than 20Mhz. So make sure you are only using channels 1,6, or 11 (try each to see if one is better) and make sure your channel width is set to 20Mhz, not auto or 40Mhz.

 

[stook1]

I'm posting from my office and don't have the exact firmware versions. Bear in mind that I have two RT-N66U routers that are next to each other. My original one is running OEM Asus firmware from a while ago, ie. sometime around a year old. The new one is brand new and presumably running a more current OEM Asus firmware. I will check the versions later. Both routers are exhibiting roughly the same performance issues on the 2.4ghz band.

In terms of devices, I have replicated these issues using the N network card on a newish Acer laptop, I don't recall the card off hand but the drivers are updated, an older desktop, and also using a Western Digital wireless extender that I setup with a lan connection to the same desktop so that it is acting sort of like a network card, I guess.

What I am really asking is whether performance issues on 2.4ghz this extreme are likely to be from interference? There aren't much/if any overlapping networks that would be interfering so this would be normal household devices that seem to be crippling the performance. Again, I am getting like 1/10th the transmission speed when testing near the limit of a usable 5ghz connection.

Stock Asus firmware is not descriptive.

The 5GHz band has much less interference than the 2.4GHz band, is this what you're seeing?

What device(s) are you using to do your tests with?

A newer laptop with the latest drivers for the wifi card and that is preferably plugged in and on the Performance power profile is the best device to be testing this with.

 

[azazel1024]

Yes it is possible to get that much interference. Especially if you are trying to use a channel width greater than 20Mhz. So make sure you are only using channels 1,6, or 11 (try each to see if one is better) and make sure your channel width is set to 20Mhz, not auto or 40Mhz.

Since the OP says he sees little overlap and I assume the other networks are resonably low signal strength (I am assuming signal family homes here), my best guess is that what you are seeing is related to other interference.

Have any 2.4GHz phones? Baby monitors? Microwaves in use? Anything remotely capable of generating a 2.4GHz signal?

ANY BLUETOOTH devices? Those work on 2.4GHz and I've seen them cause some nasty interference sometimes. What are you using for the testing.

Also, what is "turning up 2.4GHz to 200"?

 

[azazel1024]

One of the things you can do to test local, non-Wifi, 2.4GHz interference (at least if it is coming from your house) is to basically turn off/unplug EVERYTHING except the router and the device you are using for testing.

Also, don't place the routers right next to each other (unless one is off). The broadcasts from one is likely to overwhelm the other. You generally want at least a good 1ft seperation between wifi devices of anytype (hint for users of multiple wifi clients in an entertainment center, especially if more than one can be "active" at a time).

Also, what about same room testing from the clients? Similarly crippled? Sitting the client roughly 3-4ft from the router should be the ideal test location, as that shouldn't be too close to cause overload and should also ensure that highest possible signal strength to shout down any interference.

What are the link rates under network properties? Are they showing the same? Or are they linking at a different speed?

Last thought is, are these all 11n devices? Anything 11g or worse, 11b that is talking to your router? Especially if it is a chatty client, it'll slow EVERYTHING on that band way down (this applies to 5GHz for 11a clients, and 2.4GHz for the 11b/g clients). This would also apply if there is ANY 11b/g device out there chatting away, even if it isn't connected to your network. The router will still see it and only transmit when the air time is clear, and/or force resends.

InSSIDer will not show you active clients, only devices broadcasting a beacon frame, which are generally just basestations/routers/Access Points (exception to some bridges, repeaters and ad hoc).

 

[stook1]

Yes it is possible to get that much interference. Especially if you are trying to use a channel width greater than 20Mhz. So make sure you are only using channels 1,6, or 11 (try each to see if one is better) and make sure your channel width is set to 20Mhz, not auto or 40Mhz.

Thanks! Funny enough, I tried Auto and 40mhz but not 20mhz. I will try this tonight and report results + more details. Appreciate the tip, I am not that knowledgeable about this type of configuration.

In terms of positioning, the router is next to a large plasma tv. The performance issues exist regardless of whether the tv is on though. Also, I do have cordless phones and a wireless video baby monitor thing. Not sure what band they are on but these are the 3 devices that are the most likely culprits, I think.

There is also an exterior home wall (wood, but dense) separating the room with the router from the area of the house with the issues. There are also a lot of power lines running through the same wall. Considering I have usable 5ghz, which should have much worse range, I assumed this wall wasn't the issue. Otherwise just normal household stuff.

 

[stook1]

Since the OP says he sees little overlap and I assume the other networks are resonably low signal strength (I am assuming signal family homes here), my best guess is that what you are seeing is related to other interference.

Have any 2.4GHz phones? Baby monitors? Microwaves in use? Anything remotely capable of generating a 2.4GHz signal?

ANY BLUETOOTH devices? Those work on 2.4GHz and I've seen them cause some nasty interference sometimes. What are you using for the testing.

Also, what is "turning up 2.4GHz to 200"?

Sorry for the lack of clarity, the 200 was referring to the signal broadcast strength setting on the Asus configuration. I do have cordless phones and a baby monitor. Microwave, yes, but it is new and used somewhat often but not continuously, of course. Bluetooth is probably turned on on two iphones, but that is it. We aren't big Bluetooth users.

 

[stook1]

Many thanks, some great feedback here. I will do more testing tonight and report back.

One of the things you can do to test local, non-Wifi, 2.4GHz interference (at least if it is coming from your house) is to basically turn off/unplug EVERYTHING except the router and the device you are using for testing.

Also, don't place the routers right next to each other (unless one is off). The broadcasts from one is likely to overwhelm the other. You generally want at least a good 1ft seperation between wifi devices of anytype (hint for users of multiple wifi clients in an entertainment center, especially if more than one can be "active" at a time).

Also, what about same room testing from the clients? Similarly crippled? Sitting the client roughly 3-4ft from the router should be the ideal test location, as that shouldn't be too close to cause overload and should also ensure that highest possible signal strength to shout down any interference.

What are the link rates under network properties? Are they showing the same? Or are they linking at a different speed?

Last thought is, are these all 11n devices? Anything 11g or worse, 11b that is talking to your router? Especially if it is a chatty client, it'll slow EVERYTHING on that band way down (this applies to 5GHz for 11a clients, and 2.4GHz for the 11b/g clients). This would also apply if there is ANY 11b/g device out there chatting away, even if it isn't connected to your network. The router will still see it and only transmit when the air time is clear, and/or force resends.

InSSIDer will not show you active clients, only devices broadcasting a beacon frame, which are generally just basestations/routers/Access Points (exception to some bridges, repeaters and ad hoc).

 

[azazel1024]

I would look at that video monitor and cordless phone (especially the video monitor!) and see what frequencies they are operating on and regardless of what they claim, try turning them completely off and see what happens.

I'd assume the wall is not an issue. As you mentioned, 5GHz is okay enough, but 2.4GHz sucks really bad through that wall. It would be more likely to be the other way around. Granted I have no doubt it is attenuating the heck out of 5GHz, but 5GHz is working okay enough for you and you need to figure out why 2.4GHz is so bad.

For the router next to the large plasma TV, for giggles, try moving the router further from the plasma TV if you can. On/off could be a source of interference, but TVs generally have a lot of metal in them, and it is at least possible that the propogation and refractive characteristics of the TV is causing some kind of wierd feedback/reflection issues for the 2.4GHz band.

That isn't likely to be an issue, but if you have the extra wire length to pull the router a few feet away and test again, might as well.

 

[L&LD]

Just a quick tip: don't have both routers turned on when testing one or the other: they create their own interference.

 

[stook1]

Ok, I spent some more time fiddling with this issue last night. I am still having some issues but the situation seems to have changed now. Here is what I did, plus more details.

- Disconnected the new RT-N66U and went back to the original RT-N66U.
- Unplugged the baby monitor, the cordless phones, the wireless extender, and turned off the wireless on a Linksys DD-WRT E2000 running on a different floor (this is the main router, actually. For now, the Asus router is running as an AP).
- Flashed the router to the current firmware on the Asus support site.
- Reconfigured the 2.4ghz network, trying out 20mhz on channels 1, 6, and 11. I found similar results with sporadically better performance with each configuration. I also tried out 40mhz and settled on channel 6 with lower control channel configuration as giving the best performance. This was not entirely conclusive but I think I am getting the best burst speeds sporadically with this configuration.
- Reconfigured the 5ghz network and tried both 20mhz and 40mhz. I haven't fiddled with this quite as much yet but for some reason, I am now having performance issues with this band. I have no idea why. This used to work great and now it seems to be giving me half the performance of the 2.4ghz network.
- All testing was done around 6 feet from the router, which is configured as an access point, as I mentioned before.
- Also moved the router onto the floor around 5 feet from the plasma TV mentioned before and found no real difference.

Results of this work:

The 2.4ghz band does seem to be performing better but still not as good as it should be. I am getting roughly 5 MB/s transfer rate from the distant location that prompted the original post moving a 3gb movie between a server connected by gigabit to the e2000 router. I do get bursts that are faster but 5 is the rough average.

The 5ghz band seems to be all messed up now. I am getting about 3MB/s even about 6 feet from the router now. I really can't make sense of why this is so different. I was getting vastly better performance before on this band. I am the only network that I can see in insider on 5ghz.

Other random comments:

After fiddling with this for a while and thinking over other sources of interference, it occurred to me that my Honeywell thermostats are running on the RedLink wireless standard. From my reading, this should be running on 900mhz spread spectrum. Could this be the issue??? I'm assuming it can't be and I'd kind of prefer not to take down the RedLink network if it can be just ruled out as the source of the issue.

Any more suggestions for things to check? Tonight I am thinking about replicating the same testing with the new router. I don't expect a different but who knows. I am also thinking about cutting the E2000 out of the network and running just the RT-N66U in router mode to see if that makes any difference for some reason. Finally, I am also thinking about trying the Merlin firmware to see if there is something up with the latest version of the Asus firmware. I cant think of any other plausible explanation for why the 5ghz network is suddenly problematic.

Thanks for everyone's assistance again...

 

[azazel1024]

What client are you using for testing? Possible to try with a different client?

 

[stook1]

What client are you using for testing? Possible to try with a different client?

Yes, I can try with a different client. This testing was mainly conducted with a newer acer laptop and some generic wireless card in the old desktop that is in the farther away spot (that card is unfortunately 2.4ghz only). I forget the wireless card that is in laptop but I am sure it is some very conventional dual band card. I really haven't had issues with it on the 5ghz band historically. I have a new MacBook air that I can test with as well.

Just out of curiosity, does AC beamforming help with these kinds of issues? Or should I expect the same kinds of interference issues generally?

By the way, I forgot to mention two other things. First, both bands are configured for N only, so nothing legacy. Second, I did find that the baby monitor had a negative impact on 2.4ghz. This accounted for about 2MB/s in performance degradation, which is a lot, but the performance is still slow even without this device's negative impact.

 

[azazel1024]

Not likely to help. Well, not much. If you are having the performance issues testing only a few feet from the router, then any additional gain from beamforming isn't likely to help at all.

It should help some, at least at medium distances, to provide a bit of signal gain, which should increase speeds.

However, with the low speeds you are getting, unless it is client related, there is something else serious going on.

All things are not equal, but from my N600 access point (TP-Link WDR3600) to my laptop with an Intel 7260ac in it, on 2.4GHz 40Mhz in the same room I get 23MB/sec and on 5GHz 40MHz I get 25MB/sec. Client/basestation configurations will of course change that around and I know I have zero interferences (either generated or neighboring networks), so 2.4Ghz is very, very clean for me. However, even with an older network card, an Intel 2230 and an older router, a Netgear 3500L, I was getting around 18MB/sec on 2.4GHz 40MHz.

Even with 20MHz mode, I could get about 10-10.5MB/sec to/from that same old N300 router and that somewhat older Intel 11n card.

So to only manage 5MB/sec seems rather bad. The only thing I can think of in this case is a really bad client. Possibly a single stream client limiting you to only 65Mbps connection speeds (and can't do 150Mbps/40MHz mode). As an example there, my okay, but not great, single stream 11n tablet adapter hits around 5.5-6.5MB/sec in 20MHz mode and 9.5MB/sec in 40Mhz mode (2.4 and 5GHz).

 

[stook1]

Perhaps there is an issue with the CAT6 lan cable between the router and the Asus AP. Will test more tonight, as well as fiddling with the other routers I have around to see if I'm able to replicate the performance with other hardware and an even more simple setup.

 

[stevech]

By the way, I forgot to mention two other things. First, both bands are configured for N only, so nothing legacy. Second, I did find that the baby monitor had a negative impact on 2.4ghz. This accounted for about 2MB/s in performance degradation, which is a lot, but the performance is still slow even without this device's negative impact.

A baby monitor that sends analog video in 2.4GHz - occupies about 6MHz with its signal. I suggest changing your WiFi to channel 1 or 11 and hope the baby monitor signal is not present at one or the other.
The 6MHz wide signal compares to the 20Mhz wide signal of WiFi, so one or the other channel should be OK.

 

[stook1]

A baby monitor that sends analog video in 2.4GHz - occupies about 6MHz with its signal. I suggest changing your WiFi to channel 1 or 11 and hope the baby monitor signal is not present at one or the other.
The 6MHz wide signal compares to the 20Mhz wide signal of WiFi, so one or the other channel should be OK.

Right, the testing I was doing was without the baby monitor plugged in. This isn't ideal since we actually use it. However, I might be able to put it onto an electric switch of some kind so that it isn't on all the time. I'll do some more testing around the monitor but it seems that something else is going wrong.

 

[stook1]

I'm making some headway with this -- just been working late and didnt have a chance to fiddle with it more until today.

I believe there might be something up with either my CAT6 line that was running to the RT-N66U or there is a problem with that hardware after all. I went back to the second, brand new one that I bought last week and swapped out my E2000/DD-WRT router in the basement. So now the new router is running in the basement as the only AP in the house. Test results from the Acer laptop follow:

From next to the router:
2.4ghz - 14 MB/s
5.0ghz - 28 MB/s

From the upstairs location of the old AP that I disconnected (now pretty far away the router/AP in basement):

2.4ghz - 11 MB/s
5.0ghz - 8 MB/s

From the original location that was problematic where the office/desktop is located (this is now more or less one floor directly above the AP):

2.4ghz - 13 MB/s
5.0ghz - 16 MB/s

Interestingly, I think there a whole separate problem, which is now more obvious. The wireless NIC in the desktop is only capable of around 5 MB/s running on the 2.4ghz band. This is the same location as the 3rd test noted above from the Acer laptop. It is an old, generic, 2.4ghz card. That one will need to be replaced, apparently.

So anyway, this prompts a couple of new questions. The level of signal attenuation/performance degradation on the 5ghz band seems pretty reasonable to me. However, it still seems like there is some kind of interference issue on the 2.4ghz band. As a practical matter, this isn't going to be a problem for internet performance anymore since the performance is better than it had been, but it will affect my transfer rates on file transfers across the network. Do my test results on the 2.4ghz band seem normal? I feel like I should have similar performance on the two bands at least when I am testing next to the router. No?

 

[azazel1024]

A lot depends on that interference factor and also how exactly it is running.

Is it set in 40MHz mode for 2.4GHz? It looks like maybe not, as those are the kind of number running my router in 20MHz mode. I get around 14.5MB/sec absolute max near my router with my laptop, when the router is in 2.4GHz 20MHz mode.

The 5GHz numbers are very similar to what I get on my AP when it is set in 5GHz 40MHz mode.

That would certainly explain the speed discrepancy. If the only option is "auto", then odds are good it is selecting 20MHz mode for 2.4GHz.

At 7ft from my AP, I get ~23.5MB/sec on 2.4GHz 40MHz and 25.5MB/sec on 5GHz 40MHz. With my router I get ~28MB/sec 2.4GHz 40MHz and I can't equivocate with 5GHz, as I don't have the option of setting the 5GHz band to N only on my router (its an AC1750 router), but when I do set it to 40MHz channel width, I get about 30MB/sec absolute max on 5GHz (but that is still 11ac, which is going to be nominally faster than 11n for the same channel widths close to the router).

Setting my router to 20MHz channel widths I max at about 14.2-14.5MB/sec on 2.4GHz. With a wall and 30ft in the way I get around 13.5MB/sec. Move a floor up, at about the same distance, but with the floor and a couple of walls in the way and I get around 11MB/sec on 2.4GHz (with 20MHz channel widths).

If I move REALLY far away, with 50-60ft, 3 walls, floor and the dinning room table in the way I get around 4MB/sec on 2.4GHz 20MHz and around 8-9MB/sec set to 40MHz mode.