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gta2011

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WiFi Interference In Small Home

We have a client that has a small home, 1200 square feet, that about two weeks ago started having wireless issues.  They had an old Surfboard cable modem and an old Netgear router (G).  We have gone through the following steps without success:

Router
Used multiple routers (verified firmware was up to date and did a factory reset before deployment)
Tried multiple levels of encryption – unsecured, WEP, WPA, WPA/WPA2 mixed
Tried SSID broadcast and hidden


Interference
Verified client had no 2.4Ghz devices/wireless devices in house
Powered off all cordless phones and cell phones and wireless printer
Verified via inSSDer that power output was acceptable and other routers in neighborhood were not interfering with device


Devices
Tried multiple devices—different laptops and devices (tablet/phone)

Internet Connection
Tried multiple cable modems and multiple CAT5 cables
Tried multiple locations/jacks within home
Found normal speeds when plugged direct via CAT5 into router and/or cable modem


Even from a few feet away and line of sight we get .5 down and .2 up.  Direct connect produces 20 down and 2 up, either via the router or cable modem, so we know it is not a cable company issue.

What are we missing?  Why will it not work?
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redmondb
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Hi, gta2011.

(1) Has the client checked the speeds of at least some of the the laptops/tablets elsewhere?
(2) Verified client had no 2.4Ghz devices/wireless devices in house Was this done by asking the client or by using a spectrum analyzer?
(3) If a spectrum analyzer has not been used, do you have access to one? If not, could you lend the client a dual band router and try both 2.4GHz and 5GHz?

Regards,
Brian.
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gta2011

ASKER

(1) Yes, I have used personal phones/tablets/laptops that I know have no issue.

(2) Yes, it is a small house and I am very confident that no wireless devices are on in the house, except for an alarm system that is on the phone line--not wireless via cell network.

(3) No I do not have access to a spectrum analyzer so that is not an option.
Avatar of gta2011

ASKER

Maybe I should invest in an expensive, USB spectrum analyzer.  We do not have the funds to spend $100s of dollars on one unfortunately.

What about something like this?
http://www.amazon.com/Ubiquiti-Spectrum-Analyzer-External-Connector/dp/B002YKU2RA/ref=sr_1_2?ie=UTF8&qid=1352940739&sr=8-2&keywords=spectrum+analyzer
gta2011,

If you have to do any WiFi support, I consider a spectrum analyzer to be essential. Personally, I'm happy with my Metageek Wi-Spy 2.4x. However, it's a lot more expensive.than the Ubiquiti.

You know your budget and how often you have to do 2.4GHz support so this is your call. However, if I had to chose between nothing and this device then I'd grab it in a heartbeat!

edit: If you're in USA/Canada then this might be a better deal. It's a Ubiquiti 2.4GHz Router which also includes spectrum analyzer functionality. I know nothing about any of this kit, so please feel free to delete this question and ask a new one about Ubiquiti Spectrum Analyzers.

edit2: You mentioned the alarm system uses the phone line - are you sure that none of it's components communicate back to a central unit using 2.4GHz?

Edit3: Gosh, I forgot to ask the obvious question - have you tried another channel?!.

Regards,
Brian.
ASKER CERTIFIED SOLUTION
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SeeMeShakinMyHead

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Avatar of gta2011

ASKER

No, as inSSIDer showed not competeing router on the auto channel.
gta2011,

inSSIDer only shows 802.11 interference. There could be enough non-wifi interference to completely block a channel and nothing will be shown by inSSIDer - not its fault as your PC's wifi card simply doesn't register those signals.

That's what a spectrum analyzer is for! (And, given that you don't currently have one, the reason for my original suggestion to try the other channels.)

Regards,
Brian.
Avatar of gta2011

ASKER

I have purchased a wi-spy 2.4/5 device to check for interference and is scheduled to arrive today.  Any advice or tips on your past experience?
gta2011,

"2.4/5" - is that the DBx?!  Very nice!

Actually starting things is pretty straightforward. Once the device is installed, start up Chanalyzer. I only have the 2.4x so I don't know how you move between 2.4GHz and 5GHz - that's probably an option under "Wi-Spy" on the menu bar.

(1) To get a feel for the device and the s/w (Chanalyzer). have a wander around a location whose wifi characteristics you're reasonably aware of it. If things are quiet then start a wireless download from your network to your PC. The displays are pretty intuitive so it should be obvious as the traffic builds up and then drops off.

(2) Try out some non-wifi interference. A microwave is always good for general interference (just make sure there's something in it!). Video transmitters are brilliant for showing vicious localised interference. (It's fascinating to have your Wi-Spy display the huge activity on a channel that your wireless card thinks is completely clear!)

(3) It's not essential but a directional aerial that you can plug in to your Wi-Spy is very useful. If you do identify interference then moving a directional aerial around will quickly help you pinpoint its source. Otherwise you'll just have to rely on its signal strength.

(4) The Wi-Spy isn't hugely robust. I bought a very cheap pair of reading glasses, threw away the glasses and kept their metal case - its padded interior and hard shell is perfect for keeping my Wi-Spy safe when it isn't in use.

By all means post screenshots here of any results that you don't understand.

Regards,
Brian.
Like I originally stated first, just try different channels.  I use Cisco Prime and MSE for all my controllers and I have seen countless times where a device (microwave, cordless phone, electric motor, etc...) has completely killed a channel.  Controllers do a "decent" job of detected interference (to its default threshold) and then changes channels on its own.  However, your linksys probably isn't the best at doing this.  Manual is sometimes the best way to go.
Hi, SeeMeShakinMyHead.

Like I originally stated first, just try different channels.
Please read 38601086 where my "channel" suggestion was posted many hours before your post!

Regards,
Brian.
Correction:  redmondb "originally" posted the channel idea.  So, if the channel idea works, please make sure to give him FULL credit.

@redmondb, I think you read too far into that.  Its to be read more like "like I previously posted - with some emphasis".  Meaning - stop buying gear and making things more complicated and try the obvious things first - K.I.S.S.  However, if you felt I was trying to steal your thunder, I do apologize.  I sincerely didn't catch your original Edit #3.

But seriously, spectrum analyzer for a 1200 sqft home - my spleen ruptured when  I read that.
SeeMeShakinMyHead,

Thanks!

But seriously, spectrum analyzer for a 1200 sqft home - my spleen ruptured when  I read that.
That was never suggested, so please restore your spleen's equanimity by rereading the posts!
 - The OP is dealing with a client. So this is a business. Probably has a few more clients?!
 - I said "If you have to do any WiFi support, I consider a spectrum analyzer to be essential." - which I squarely stand over. A spectrum analyzer identifies bad non-wifi interference pretty much instantly (edit: while it's occurring). How long would it take to definitively exclude such interference without an analyzer. How many client calls would it take to repay a $54 investment?
 - I also suggested that the OP look into the Ubiquiti router as that apparently gives him a spectrum analyzer for "free".

Regards,
Brian.
@redmondb - That was never suggested, so please restore your spleen's...
That was inferred by your comment:  "If a spectrum analyzer has not been used, do you have access to one?"  

However, I am not trying to start an English battle with another fellow IT warrior.  I am just a bit cynical in my older age and to combat the weariness that IT can have on one's lifespan, I add some levity.  Perhaps the intruduction of my spleen's condition may have been a tad over top.

I am aware that this is someone's business and I am certainly not belittling that one bit.  I have been in the SOHO trenches before - we all have at some point.  I was just stating that all the CGI effects of should be held off until the most simplistic approaches have dried up.
SeeMeShakinMyHead,

Plugging in a Wi-Spy, starting Chanalyzer and definitively identifying a non-wifi interference (assuming that's the problem) - less than 120 seconds.

I'm happy to agree to disagree!

Regards,
Brian.
Avatar of gta2011

ASKER

We tried a different channel after using with spy and solved the issue.  It turned out that there was a lot of interference on 2.4/11.
Last laugh to you, SeeMeShakinMyHead!
Well, I would have just tried a different channel and it would have been fixed in minutes. Hooray f
For keeping things simple.

Dang mobile version - submit too close to top of keyboard :(
And the points really should be split at worst. Redmond did have a valid point in his post too.
SeeMeShakinMyHead,

And the points really should be split at worst. Redmond did have a valid point in his post too.
...doesn't really tally with...
Correction:  redmondb "originally" posted the channel idea.  So, if the channel idea works, please make sure to give him FULL credit.

I think you should just settle for the points!

Brian.
I wanted to at least split the points with you. Dang man, trying to be nice and this is what I get?!?  Well, my idea was quick, simple and to the point. Not like the long diatribe that you were posting.  Cya on the battlefield.
Cya on the battlefield.
Ah, that explains things!

All the best,
Brian.