Wireless network in a big house:

[Hard Ball]

I manage the network at our house full of University students, on a volunteer basis. This house has about 20-25 computers connected to this network. We recently swtiched to a 1.5 Mbit DSL line, and tried to improve the reception of the wireless signal in the house by getting a second router 802.11g ; this new router, we placed on the second floor, and is supposed to have a more powerful signal than the first.

One of the things that I found is that the there are a number of other networks in the neighborhood. I have detected 30+ other routers' SSIDs, and some of them project a fairly strong signal. Most of them are clustered around channel 6 or 11. So I set the two routers on channels 1 and 4 respectively, trying best to avoid interference.

But the new router on the second floor always seems to be on or off in terms of reliably transmitting signals, and at certain times of the day it would hardly work at all, while at other times it seems to be flawless.

There is also a lot of problem getting a clear transimission if the computer is near the periphery of the house, such as a room on the corner of the third floor, which would get fairly good signal, but sometimes not being able to access the web.

I have tried a number of different things to try to adjust the performance; moving locations of the routers (they are connected by LAN cable, with the downstairs old router being the root); I tried to use a number of different channels (the higher channels are absolutely atrocious); and also adjusting MTU and fragmentation sizes. Sometimes it works well, but other times I can't even get on to the router administration page.

Does anyone have any other suggestions. I'm sure that there are a lot of you who may have some good ideas.

Please let me know anything, I mean anything; I'm getting exasperated.

 

[nweaver]

I would set both to channel 1, but only if there is nothing on channels 2,3,or 4. Channel 4 shares some of the same frequencies as channels 6, so if that is already crowded....

check the client utilities, make sure the wireless cards are using full power (just to check) as some may throttle down their transmit power, causing issues.

Use netstumbler to find the best channel/ap placment for the lowest Signal to Noise ratio. (www.netstumbler.com). Use this to see what's happening during peak times when it's not working.

 

[Hard Ball]

Originally posted by: nweaver
I would set both to channel 1, but only if there is nothing on channels 2,3,or 4. Channel 4 shares some of the same frequencies as channels 6, so if that is already crowded....

Thanks,
OK, I can try that,
but is putting both routers on the same channel, which are physically close to eachother a good idea?

check the client utilities, make sure the wireless cards are using full power (just to check) as some may throttle down their transmit power, causing issues.

I will have the people check their wireless equipment.

Use netstumbler to find the best channel/ap placment for the lowest Signal to Noise ratio. (www.netstumbler.com). Use this to see what's happening during peak times when it's not working.

Yes, I have used netstumbler to do that, but often it shows good SNR, but the signal of the upstairs router is on and off, meaning one second I see good SNR, the next second there would be no signal at all; that is whenever we are having connection problems. Any ideas.

 

[azev]

Maybe a bad AP ? I think the issue with your client having alot of signal but no network access is because they might have connected to a rouge AP.
I know my computer does that all the time. I have multiple ssid configured on my laptop because I travel alot. One of them is my neighbour SSID (i asked permission to use his network for me to test my published server). I've notice my dell wireless configuration sometime switched to my neighbour SSID eventhough it has much weaker signal than my own AP. I missed my old cisco card and its client, having profiles in the wireless config enable me to only have one SSID, somehow this locked the wireless card to only connect to a certain SSID.

 

[Kibbo86]

I've heard that 2.4GHZ phones use channel 4. That may be the source of intermittent signal drops.

 

[nweaver]

Yes, it's fine (and probalby better in a noisy enviroment, if it's the only open channel) to put them both on 1 (I have 3 100mW radios all within 3 feet on the same channel, no problems).

I would move the client close to the AP, and test it, to make sure it's a range/connection/interference issue rather then something else.

You could also ban cell phones/2.4Ghz phones (unplugged from power) and microwave use for a short time to test it and see if it's noise.


2.4 Ghz phones frequency hop all over the spectrum, I wish they would stay on one channel. Their cannels also (as far as I know) don't line up with 802.11 channels.

If you can find documentation on the phone (I only use 900 Mhz) I can get the exact frequency used for different B/G Channels off my Cisco AP's

 

[amdskip]

What routers are you using? You need something other than a router from best buy for that load. Actually your connection probably isn't good enough to support than many users along with wireless. You would be better off with a couple lines and some sort of Quality of Service setup but I'm guessing $$ is restricted and you can only make due with what you have.

 

[nweaver]

my wireless ISP runs 50 users off a T1 line just fine...

 

[Hard Ball]

thanks for all the responses so far, all are great suggestions.

The routers we are using, one being netgear WGR614 or a similar router, that's downstairs; And I think the upstairs one is LINKSYS WRT54GX2


Some acquaintance, who is a professional IT admin came and took a look at it, and found a bug in one of the router's firmware, and he has since updated it. So one of them should be working better, the one downstairs, the netgear. But we still have no idea about the router upstairs.