weird problem with wireless network

[jfdramis]

Hi,

I have spent many hours at one of my client's place trying to set-up a decent wifi network for their home and since the beginning i have had some very weird problems. To make a long story "short", its a big home (around 7500 sq ft) on 3 floors. I tried many different solutions (different brands of AP's, Extenders, routers...). Right now they have a Netgear R7000 router on the main floor and on the first floor i installed a Netgear EX6200 extender. 2.4GHz is on auto channel and 5GHz is on channel 143. Most of the time the wifi works really well throughout the house but at certain times during the week/day, the wifi speed drops significantly for no apparent reason. On speedtest.net i get an average of 12Mbps pretty much everywhere in the house but when this issue happens, the speed drops to something like 1.1 Mbps even if i am in the same room as the router. At first i tough it might be the internet connection but tested the speed hard wired in the router and everything was fine. At this point i tried everything i could think of. Anyone has an idea of what the problem could be ? Could something be cause enough interference that the wireless signal drops by that much even when being less than 15' from the router (in line-of-sight)?

Thanks in advance!

 

[abailey]

My guess would be interference. You can definitely get interference even right next to your WAP. Have you done a site survey? You need to do a survey with a Wifi Analyzer app. Also is your extender wired back to your main router? If it is extending the signal wirelessly then it is interfering with the main router itself as they have to use the same channel. It can be a killer if someone decides to stream video through an extender.

 

[jfdramis]

Here is a bit more info:

-router and extender have different ssid's
-extender is not physically connected to the router
-when the problem occurs, i am connected to the router's ssid to be sure the problem is not with the extender and am less that 15 feet away
-wireless signal when i test on speedtest.net is always full bars (iphone and laptop)
-did a basic site survey with inssider
-the router was on top of many electronic devices (dvd player, hd decoder and other equipments) so i moved it on an higher shelf, now its about 3" away from the rest
-there was a cordless phone close so i moved it to the other side of the room
-problem is on the 2.4GHz, didn't try to see if it also occur's on 5GHz

So with all this can it still be an interference problem that could cause such a major speed drop at such a close range ?

 

[stevech]

Interference from other nearby WiFi creates competition for air time access. Clear Channel Assessment (CCA) or CSMA (carrier sense - CCA, with collision avoidance, or CSMA/CA.

A neighbor's signals, even 1 or 2 channels different, can cause CCA delays and that leads to slower throughput if it gets excessive. When a neighbor streams HD 1080p or some such (not Netflix), there are likely bad CCA delays. This can be a NAS through WiFi to a viewer.

Weak signals from neighbors, weaker than the "yes" threshold in signal strength for CCA, lead to corrupted bits and higher retransmissions for error correction. That too leads to lower throughput - but a signal from your WiFi that's many 10's of dB stronger, will tend to mitigate this.

Signals from non-WiFi sources usually lead to CCA delays. Examples of these are baby monitors pushing analog video without CCA near your channel. Microwave ovens, esp. old ones that have leaky door seals, can slow speeds, mostly in the upper part of 2.4GHz. Rather rate today.

This assumes too that you have no intra-system interference (self induced interference). This can happen if you have the WiFi router and access points on the same channel, or within about 2.

A neighbor using 40MHz in 2.4GHz is a spectrum pig. That's 2/3 of the band. If lightly used, OK, not so many CCA faults.

5.8GHz ( ISM) band can have a lot of non-WiFi signals. It's less populated so far, but on the rise, quickly.

 

[KGB7]

3" away from a big stack of electronics is not enough. It needs to be at least few feet away. All those electronic devices can cause a havock on WiFi.

Always set the WiFi channel manually. Find.the best channel that works in that house. Today's routers are too dumb to do it on their own.

Don't use speedtest.net, only use ISPs speed test.

Play around with settings in r7000, one wrong setting can make things far worse.

 

[jfdramis]

First of all, thanks for the replies and all the info given!

I moved the router 3' away from the other equipment and not 3"!

I know that if the router configuration (if wrong) can cause this kind of problem but i did some tests with another router (Asus RT-AC68U) and had the same problem.

Now that i know that the neighbor's wireless networks, even if they have a very weak signal can cause such problems, i will re-test with inssider and chose the best channel for 2.4GHz and set the router to a fixed channel.

Should i leave the 20/40MHz setting to auto or manual (20 or 40 ?) ?

Thanks again!

 

[jfdramis]

From prev post :

Should i leave the 20/40MHz setting to auto or set it to manual (20 or 40 ?) ?

 

[KGB7]

Either 20 or 40. Depends on how busy the neighborhood is with other wifi routers.

I would keep it on 20, it will give enough bandwidth for a multiple devices to stream movies.

Test both out just to see how it works in that house.

 

[jfdramis]

Ok, i will try that! Thanks a lot!

 

[jfdramis]

I forgot to ask, once i will have done my wireless analysis with inssider and found the less crowded (or unused) channel, is it still recommended to stick with channels 1, 6 and 11 ?

 

[abailey]

I forgot to ask, once i will have done my wireless analysis with inssider and found the less crowded (or unused) channel, is it still recommended to stick with channels 1, 6 and 11 ?

Yes as those are the only non-overlapping channels. Anything else will at best be the same, and most likely worse.
http://www.metageek.net/support/why-channels-1-6-and-11/

 

[KGB7]

I forgot to ask, once i will have done my wireless analysis with inssider and found the less crowded (or unused) channel, is it still recommended to stick with channels 1, 6 and 11 ?

If 1,6,11 are overlapped. Then do continue to use of those channels. At the end of the day, you'll have to test all channels and use one that work best in that house.

I'm my neighborhood, the WiFi is saturated and all channels are overlapped, but my WiFi works just fine. 25 WiFi ssids, and that's just inside the townhouse on the grownd floor. Using WiFi analyzer app on galaxy s4.

Its a time.consuming process to.find what works, but you'll get there.

 

[jfdramis]

Ok! Thanks for the anwers! Greatly appreciated!

Its the first time i have a problem like this. I have set-up countless wireless networks in all kinds of places. Some were super crowded with tons of surrounding networks and others nothing but never had this problem losing so much speed even when being in the same room as the router. I will test all (non-overlapping) channels and check with inssider to find the best channel for this house.

 

[byonik]

Another consideration is that some APs share channels well, and others not so much. You should definitely play around with static channel assignments testing all three non-overlapping channels (1/6/11) to see which one offers the most consistent performance.

Also, many of the nearby APs will be set to auto, and by selecting a static channel for your AP, you may be able to push them of your selected channel all together. Again, some routers will be easier to manipulate than others, and it can take a few hours or days to see results.

At my house, I have been successful in "owning" channel 1 and pushing my neighbors APs onto 6 and 11.