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I am baffled by what I am experiencing on my home wireless network. My 802.11g AP (USRobotics 9106) is setup on Ch 11, with WPA-PSK encryption. My neighbor sometimes turns on one, two or three APs, all with default settings, no security, and on various channels, some 6 some 11. When his APs are on, though their signal strength is around 55%, my AP with security does not show up any more in site surveys, does not respond, and my clients cannot connect. If I reset my AP to default values with no security, my AP shows with 96% signal strength and I connect with no problems. This happens on win2000 and XP clients.
Any ideas of what is happening and how to overcome it and put some security on my network will be appreciated.

Sounds like co-channel interference going on with the APs.

Try enabling MAC Filtering and see if that improves your performance or ability to detect your AP.


I'm saw something similiar but not what your seeing. The battle is between a Netgear AP @ 108Mbs turbo mode on channel 6 , a Linksys AP @ 54G on channel 11 with encryption enable on both APs.

There are a couple of others APs are around on channel 6 and 1, but they are not affecting the performance like the Netgear 108 mb box is doing.

It is closer to us than our Linksys, as we share the same building. I think the turbos combine the channels and use more spectrum causing a bleeding over into the channels to the left and right. I moved to channel 1 and am OK. I can still connect to my preferred AP with just WEP enabled.

Even though his AP overpowers our network the Linksys AP is connected to everytime. If you have the option for preferred AP SSID use it.

Hope this helps

Channel one and automatic channel selection cause my AP to disappear completely from the list of available wireless networks, and I had to do a hw reset.
I have now set it up with just MAC filtering, and on Ch 11, no other security. Let's see how it goes.
thanks.

I'm not 100% sure, but I believe both Netgear and USR use the Texas Instruments radio chipsets.

Awhile back I had a USR .11b AP that a friend used and was having problems with. When I analyzed the WLAN, I noticed that beacons were being sent every 10ms instead of the normal 100ms and that it supported Long preamble only with no way to support short. It was a pretty old AP/router combo.

To possibly help alleviate your USR issues, if your neighbors always use channel 6 or 11, then set your AP to channel 1. Also, try and see if the issues I described above are in place (10ms / long only) and then see if you can modify them without killing your WLAN clients -- my friend also had USR wireless clients that were fine with those settings, the problem was that everything else I tried to add to the network that was non-USR wouldn't work or had major throughput problems. So much for "standardization".


Netgear's TurboMode does utilize "channel bonding" - using more than one non-overlapping channel to accomplish increased throughput while simultaneously squashing the rest of the network.

Joel

The standard settings are:
Beacon interval is set to 100
RTS Threshold is 2347
Fragmentation Threshold is 2346
DTIM Interval is 1
No way to change the preamble on the AP.

As posted before, using channel 1 hides my AP completely.
The neighbors devices are Netgear, Belkin and a USR 5450.

Could an amateur radio antenna on his balcony affect my wlan? I thought it would use different frequencies.

thanks again.

Yes , the amatuer radio could be doing the 3rd or 5th order haromonics trick on your spectrum. Most likely it is the 3rd order from 804 Mhz X 3 you get 2412 Mhz which equals channel #1 of the spectrum.

why do you say "trick"?
Is it something he could avoid? Is it intentional?
thanks again

I say "trick" because it blind sides you and you don't see it without a rf power meter or analyzer as it can be a sporadic disturbance. RF analysis can be very complicated art/science. When some one has a device that is in the same or even different frequency ranges of your device it can possibly interrupt your device. In WLANs we transmit low power RF signals. The bleeding over of spurious signals that are multiples of the frequency you are utlizing can hamper or shut down your device if the conditions are right.


Hint Hint, in the US make sure your device meets the FCC part 15 specs and better yet if you can the device have the WIFI compatibility stamp on them.

If you are in Italy it should meet the standards established there.

I saw this once in an install where we couldn't figure out for the life of us why we where not recieving our signal. 50 feet away we could recieve the signal but in side that room, we had a very weak signal. It baffled me, until I investigated there I saw the following; the room was surrounded by cable tv amplifiers , power transformers, and emergency radio devices.


This gives support to the need for a Site Survey. You never want to just do a blind analysis and throw up an AP or any other device not knowing what is around you. That is the trick!

I suggest downloading the trial version of a wireless protocol analyzer such as CommView for WiFi from www.tamosoft.com and taking a look to see if you're seeing frames on channel 1. If so, look at the noise level shown in the decodes of each frame. If you're not getting approximately 10 beacons per second, and your noise level is very high, perhaps greater than a -80dBm, then I'd suspect the amateur radio or the channel bonding problems as being your cause. It's better to select channel 11 (the other end of the 2.4 GHz range) and have to share that frequency than to be in the path of high-powered narrowband interference. It's time to switch to 802.11a. ;-)

Devinator

Thanks for the valuable information and suggestions.
I have been using ch 11 for a few days now, and everything seems to go much better, even if I share the channel with my neighbor's APs.
I am using MAC filtering and hiding the SSID.
I may just try to setup WPA-PSK again.