Weird wireless issues in small office

[Gordy]

I've come across a slightly strange issue that has me completely flummoxed. I've been installing and fixing networks for many years and never seen anything like it. I was wondering if anyone else had seen anything similiar or could think of any suggestions.

The office is a small one and is in a small room with three desks. In the hallway there is a small data cabinet with networking patch panels and a switch. A while back they suddenly lost wireless connectivity, I tried a few things but narrowed it down to a faulty router. However the replacement router also didn't allow anyone to connect to it via wifi. I tried lots of things, but the only way I could get it to work was to move it into the office itself. Now it's not a signal strength issue, there was no extra distance or signal loss in the two sites. The only real change was a different power socket.

It has been running like that for 6months now with no downtime at all, however they had a power cut the other night and this brought everything down. The next morning the Router had crashed and there was no wireless available. Swapping to a spare router this worked for about an hour before that stopped allowing wireless devices. Restarting several times eventually brought it back to working wireless for half a day before again going down.

So today I tried replacing the router for a completly different brand, Netgear DGN2200 before Apple Airport Express with a Netgear DG834 wired router. With this in place I was still having issues getting all the laptops and devices connecting. About 50% would and 50% wouldn't even see the network. Those that did connect lost the network regularly despite having perfect signal.

I tried reseting and restarting with no success. The only thing that seemed to work was moving the Apple Airport extreme to a room down the hall well away from the office.

So I'm now very confused. What I am suspecting is that there is something in the office that is causing interference with the Wireless. There are a few other networks around, but all on different channels so I don't think they are causing it. The Airport and Netgear work on different frequencies so that should eliminate other networks?

Could it be something else emitting EMF that is causing this? I suspect the emergency exit light which was replaced sometime close to the first issue happening and kicked into action because of the power failure, but I don't know if this can be the cause?

Any suggestions would be great, I've had to put a wired network in place for the time being, but thats not ideal.

[DanceswithUnix]

Are you actually seeing a drop in signal strength?

Dig out a tablet or smartphone, on my Android phone I use "WiFi Analyzer" which shows all the signal strengths in the area in a really good graph so you can see how much signal you are getting on which channels. Turn your router off, and see what the background is. Now you can make an informed decision on what channel you should be using for your wifi.

OK, now some random thoughts in case one of them works

Are you using the same power supply for these routers? They seem pretty standard, and part of the standard is that they last a year or two then get noisy so equipment acts up a bit and then they die.
It sounds like this is a standard router, in which case it will be acting as a DHCP server. Could you have another DHCP server on the network? That would get you your 50% problem as half the laptops would get duff network config by basic chance.
If it is WiFI congestion, can you get a dual band 5GHz WiFi access point? A bit costly, but much less cluttered radio spectrum and most laptops and phones seem to be able to use 5GHz these days.

[Gordy]

Thanks

No drop in signal strength, it goes from full to nothing, not even showing in available networks. Then sometimes it will reappear.

I've looked at all the channels being used and picked ones that aren't being, but that hasn't helped. All the other networks in the area are far away and at the limit of their reception.

I've replaced the psu's for the routers I've used three different ones.

No other dhcp servers on the network, I've checked.

The Airport extreme is a 5ghz one, but that wasn't any better.

The laptops are a variety of different makes/models/os's and all connect sometimes just never all at once. All have been connecting fine up until this week.

It's the bizzare nature of it. I've even powered down anything I could in the office to make sure it wasn't that. The only thing I haven't and cannot yet power down is the fire exit lighting system.

[SUMMONER]

When London Transport was digging in Dalston (East London), we had no working WiFi for ~ 5 weeks. Tried 5 or 6 different routers, nothing would work reliably. Then everything suddenly just started working again.

Never figured out what the cause of it was, but clearly they must have been using some machinery that was emitting massive amounts of interference.

they had a power cut the other night and this brought everything down. The next morning the Router had crashed and there was no wireless available...

The only thing that seemed to work was moving the Apple Airport extreme to a room down the hall well away from the office.

Are you saying that if you move the router somewhere else in the building, you can then connect to it wirelessly from the office in question?

Have you tried connecting a laptop to a "battery powered" WiFi hotspot? e.g. your mobile phone

[Stin]

There are many things that can effect wifi signal.

Water is really good at absorbing wifi signals. If you see someone standing in direct line of sight between your client and your AP, you can see the signal drop and come back as they move in real time.

There are many other things that use the 2.4Ghz range, and do not show up on tools like wifi analyser or InSSIDer.
I've heard reports that wireless TV extenders can wipe out wifi signals. So can baby monitors, and even IR intruder detectors for burglar alarms.

The obvious thing to try is fixing the wireless channel. Stick to 1, 6 or 11 as these are the non overlapping channels.

[Stin]

Re: 5Ghz,

I actually had a problem with this recently.
I had 2x 5GHz wifi Access points.

My iphone 5 could see both AP's no problem.
My 5GHz PCI card from Edimax could only see 1.

It turns out that there are regional ranges. The AP that could not be seen by my Edimax PCI card was operating in a band that was out if its range. If I changed the band to a lower band, it could.

It would be worth investigating.

[Rob_B]

Anything locally that isn't a router (so wouldn't show up on wifi analyser) ?

Console (my PS3 puts out a signal in standby)?
Vodafone sure signal?
DECT phone?

[Gordy]

I was back in the office today and still the issues are there. In the end I hooked up a wired network for them to get them back up and running.

I put the Airport extreme in another room and the devices like their printer are connecting fine to that.

I ran a wireless scanner to see if what channels were being used locally and none were using the airports channels.

When London Transport was digging in Dalston (East London), we had no working WiFi for ~ 5 weeks. Tried 5 or 6 different routers, nothing would work reliably. Then everything suddenly just started working again.

Never figured out what the cause of it was, but clearly they must have been using some machinery that was emitting massive amounts of interference.


Are you saying that if you move the router somewhere else in the building, you can then connect to it wirelessly from the office in question?

Yes if the router is in another room computers connect to the router fine. It's only when the router is physically in the same room that the issues seem to happen.

Interesting anecdote as it all lends to my suspicion of the dodgy emf output from something.

Anything locally that isn't a router (so wouldn't show up on wifi analyser) ?

Console (my PS3 puts out a signal in standby)?
Vodafone sure signal?
DECT phone?

Nope I've turned off all kit that I can without turning things like the fire alarm system off.

There are many things that can effect wifi signal.

Water is really good at absorbing wifi signals. If you see someone standing in direct line of sight between your client and your AP, you can see the signal drop and come back as they move in real time.

There are many other things that use the 2.4Ghz range, and do not show up on tools like wifi analyser or InSSIDer.
I've heard reports that wireless TV extenders can wipe out wifi signals. So can baby monitors, and even IR intruder detectors for burglar alarms.

The obvious thing to try is fixing the wireless channel. Stick to 1, 6 or 11 as these are the non overlapping channels.

I'm hoping the EMF meter I've ordered will let me detect those things to isolate them.