Help! Wireless connection repeatedly dropping

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The Chairman 21 years ago

Ok, here is the situation: One wireless laptop (XP Home SP2), the rest of the workstations are wired. Brand new Linksys WRT54G router and Linksys Wireless G Network card. Very very simple set up that I have done dozens of times before. The signal at the wireless user's desk is excellent.

However, when the laptop user logs on to AOL, he will often (sometimes as much as every 5-10 minutes throughout the day) get disconnected, then reconnected immediately afterward. Also, from what he says, after the first drop, the networked version of Quickbooks stops working. I am assuming that this is because he has lost the connection to the Quickbooks host on the local network. The other users seem to have no problem with connection stability. Another user uses AOL and they are all on AIM, and the connection doesn't drop for them.

However, when I brought the laptop to my house, it stayed connected to my wireless network indefinetly, with no droppage problems whatsoever, for over 5 hours.

What I have tried so far:

disabled the XP firewall uninstalled and reinstalled all the networking devices on the laptop replaced the router and wireless card (this was before the problems, as they needed to upgrade to G anyway.)* changed to the Wireless channel from 6, to 1, to 11, to 10.

*side note - they were having problems with their last Linksys B router, where the laptop couldn't see the SSID anymore. Could see all the neighbors, so I think it was a channel interference thing. Rather than troubleshoot, we simply upgraded.

Anyway, any suggestions on what else I might try? They have a wireless Panasonic phone system set up in their office. Could this be causing the interference? I tend to think not, as things were running fine with the wireless network for months before when they had the phone system. Could there be something else in the building that is causing the drops that I should look for? HELP!

Thanks,

Ryan

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Airhead 21 years ago

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buying

My cheap solution is to find you a Proxim RangeLan 2 7400 FHSS adapter card. I found a new one on ebay for about 10.00. You can download the utilities from Proxim. It has a site survey tool called snoop that scans the

2.4ghz range. Works very well. I found that my garage door opener is a source of continual interference in the channel 6 area with it. Another thing for dsl connections, I would set the router keep-alive setting to 0 or 1 for optimal dsl connection performance. Default is 30 secs on a wrt54g. Not that it will help the wireless side but, dsl if left idle will disconnect and then reconnect based on the keep-alive setting. In other words the wrt54g checks every 30 seconds to see if dsl is up and if not redial it.

channels...?

something new,

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Jeff Liebermann 21 years ago

The Panasonic phone system could be causing the problem. Most are frequency hoppers which clobber ALL channels. Sounds more like a classic case of 2.4GHz microwave oven interference. Tracking down the culprit is going to be rough without a spectrum analyzer and more frequent events for testing. If this office has a glass wall with a view of the outside world, I would try moving the access point away from the view.

Other possible sources of 2.4GHz interference are: Microwave oven. 2.4Ghz video or security camera link (X10). Bluetooth devices (mouse, phone, PDA, headset, cell phone, etc) Portable wireless TV camera used at sports events. Frequency hopping cordless phones (Panasonic Gigarange) 802.11b/g wireless keyboards, PDA's, and cell phones. 2.4GHz game pads and controllers. RF Excited Lighting (Fusion Lighting). 2.4GHz baby monitors. 2.4GHz ham radio operation. WISP (wireless internet service providers) which may be using non-802.11 type of modulation (i.e. WiMax).

This might be worth viewing:

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The Chairman 21 years ago

Jeff Liebermann wrote in news: snipped-for-privacy@4ax.com:

Thanks Jeff. Are there any PC programs that do some form of Spectrum Analyzing? That YellowJacket looks awesome, but I can't justify buying something like that for just this one situation.

I would imagine that a laptop would be able to do some form of this, because of it's inherent properties it's always scanning the channels...?

Also, would you say that based on what I posted I can pretty much rule out any other hardware or software issues? I would think there's nothing else to try. What I am thinking is that maybe a neighbor just got something new, and that is interfering with the network now.

Maybe I'll just run some CAT 5 to the guys desk! Seems like that would be the easiest of all the solutions.

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Jonathan 21 years ago

This sounds a lot like the ongoing problems I have with my Centrino laptop at home. Based on my experiences (which may or may not be similar to what you're seeing), I'd say try these 2 things as a test:

1) Move the problem laptop further away from the AP, if it's closer than about 20ft. 2) Temporarily force the WRT54G down to 802.11b only, and see if the connection improves.

Hopefully these will give you some clues.

good luck, Jonathan

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Jeff Liebermann 21 years ago

Yes, sorta with some limitations. Proxim made an frequency hopper that can be used as a crude spectrum analyzer. RangeLan2 7400 card. There is spectrum analyzer software called "snoop" available. You'll also need to reflash the card with tweaked firmware so that it doesn't transmit. |

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cards can be found on eBay for about $20/ea.

I also have the same FHSS card in a Symbol PPT4340 oversized PDA. |

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can be found for about $150. There's a one for $549 on eBay which methinks is excessive.

The catch is that it's not terribly sensitive. I had to hack mine to add an external SMA antenna connector. With the supplied rubber ducky, it could barely see my access point at about 30ft. Fortunately, my leaky microwave oven was VERY obvious. However, I couldn't see the neighbors oven at about 100ft. If you're going to use this setup, you'll need an RF pre-amplifier and a big antenna.

There's also this program: |

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has an even cruder spectrum analyzer feature. I never could get it to work.

I also have a few ancient Teletronics 802.11 cards which comes with marginal site survey software.

One of the local WISP (wireless ISP) tech types may have one or possibly a spectrum analyzer. I usually borrow long before I buy.

Your 5 hour home test fairly well ruled out any wireless hardware issues. It might be something dumb like the power save on the laptop or seperate power saving features on the wireless card. It's worth a double check, or possibly disabling all power save features to be sure. They're in the wlan card driver, Windoze desktop, and BIOS setup. Check them all.

My guess is still some sort of interference. However, we can rule out most of the list I posted as it's unlikely that these would operate only for a few minutes perhaps once or twice per day. Only the microwave oven fits the use pattern.

It's also possible the office broadband connection has an idle timeout or that the ISP is juggling DHCP IP addresses just to irritate anyone running servers. This is rather common with PPPoE and would be fatal to secured connections such as QuickBooks Online while barely noticeable for typical web browsing. I know you said that nobody else is affected, but it may be a bad timing or bad luck issue.

Add to the list: City installed metropolitan LAN. Coffee shop hot spot.

Yep. Wireless is nice, but wired is much more reliable.

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Jeff Liebermann 21 years ago

I forgot to mention that the software doesn't run on XP and some WinCE mutations. Also, I've been told that hacked firmware flash is un-necessary if you simply place the card in the "master" mode.

Some more links on the card. The photos should give you some clue what to expect.

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spam 21 years ago

Where on the proxim site is the app called snoop, it sounds exactly what I need for a problem I am trying to solve.

Regards Paul.

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Jeff Liebermann 21 years ago

"Snoop" is not a stand alone program that can be downloaded and run independently. It's a feature built into the Windoze drivers for the Proxim RangeLan2 7400 cards. It works with everything from W95oemSP2 to W2K, but does NOT work with XP.

The program is rather clunky. There are 3 scan speeds. Slow takes about 60 seconds to scan from 2400 to 2483.5 MHz. Fast takes about 10 seconds. If there's no traffic, it can barely see the beacons from my access point. If I'm downloading furiously (or ping flooding with large packets), I can see what looks like DSSS spectra on the slowest speed. Medium has some holes in it, and fast looks like a mess.

My leaky microwave oven is very obvious. IIt also shows a pronounced drift from the upper end to the lower end of the band as it warms up. The oben's spectra is only about 5 MHz wide. I can see my signal generator quite nicely. I wish it had a peak hold that would hold bars between multiple sweeps. Anyway, it's better than nothing.

Given some spare time, I can post AVI video clips of the various screens and emissions using my digital camera.

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spam 21 years ago

Thanks Jeff.

I think I have sourced a card from Ebay, wonder why it does not work on XP, when it works on 2000? Not that it matters that much, I have an old portable knocking about that would run Win2k.

Cheers..

Paul.

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