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Diagnose a bad Wi-Fi connection

3 comments

TAGS:network diagnostics, Wi-Fi
IT TOPICS:Laptops & Netbooks, Mobile & Wireless, Networking, Windows & Microsoft

By Lincoln Spector, PC World

B2CAC asked the Answer Line forum why his laptop couldn't connect wirelessly to his router.

Network problems are the thorniest to resolve. They've been known to reduce my vocabulary to curses so strong they'd embarrass Quentin Tarantino.

A big part of the challenge is figuring out where the problem lies. Although I can't promise a solution to B2CAC's particular problem (or anyone else's), I can suggest some simple tests that will help you isolate the cause. Once isolated, it will be easier to fix.

Move around the house. You may simply be trying in a room with a bad signal. Try accessing the network or the Internet from a room closer to the router. If this solves the problem, but you really need access when in the room where you couldn't get Wi-Fi, consider buying a HomePlug device.

Run Windows' network diagnostic. To be honest, I've never seen this fix the problem in XP, but I have in Vista. Right-click the tiny Network icon in the system tray and select Diagnose and repair (Vista) or Repair (XP). The icons on the left are approximations of the ones in the system tray -- the ones on your PC may differ due to network status (for instance, they may have a tiny, red x). Keep your fingers crossed while Windows tries to find and correct the problem.

Try Ethernet. Move the laptop into the same room as the router and connect it with an Ethernet cable. If you still lack network and Internet access, the problem isn't with your Wi-Fi. See How to Troubleshoot Your Home Network for further suggestions. (My thanks to mphenterprises for suggesting this fix in the original forum discussion.)

Turn off Wi-Fi Security. Bad passwords and incompatible encryption standards cause a lot of Wi-Fi problems, and temporarily turning off encryption will tell you if they're causing yours. I can't tell you exactly how to do this; check your router's manual for directions. You obviously don't want to keep your network unprotected for long, so you'll have to figure out what the problem is so you can turn encryption back on again. Make sure you're using the correct password and that your PC and router support the same encryption protocol.

Try another Wi-Fi enabled device. This could be another computer, a smartphone like the iPhone, or an iTouch. If you don't have anything like that handy, invite someone over who does. Luckily, most Wi-Fi-enabled devices are portable. If that device can access the Internet, the problem is with your computer. If it can't, the problem is with your router, modem, or ISP.

Try the laptop elsewhere. Take it to a café or library that offers Wi-Fi and see what you can do. If you can access the Internet from there, the problem isn't with your PC.

Hopefully, after all of these tests, you'll be able to find the problem and fix it. And if not, you'll at least know which company to call for technical support.

Add your comments to this article below. If you have other tech questions, email them to me at answer@pcworld.com, or post them to a community of helpful folks on the PCW Answer Line forum.

Reprinted with permission from

For more PC news, visit PCWorld.com.
Story copyright 2008 PC World Communications. All rights reserved.

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what really brings the 5GHz

Submitted by Sophie on November 19, 2009 - 5:09 A.M.

what really brings the 5GHz network? so you can get better connection or is it also only fake?

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Wi-Fi incompatibility

Submitted by Brett Glass on October 29, 2009 - 3:21 P.M.

Lincoln's suggestions are good ones, but there's another possibility not mentioned above.Some vendors of Wi-Fi chips have intentionally made their chip sets incompatible with chips from other vendors, and refused to fix the problems, so as to get a competitive edge. The biggest culprit in this area is Intel, which made the internal Wi-Fi chips it produced for laptops (originally under the "Centrino" brand name) incompatible with access points that used the rival "Prism" chip set from Intersil. Even when faced with complaints by users who couldn't connect to their existing networks, Intel refused to fix the incompatibility (even though it could have done so by updating the driver software). Makers of routers and access points retired their Prism-based products to avoid compatibility problems with the millions of Centrino-based laptops that were hitting the market.

So, my advice to this reader would be to try an external Wi-Fi adapter on the same laptop. If it works, then the problem is the laptop's internal Wi-Fi chipset.

--Brett Glass (former Answer Line columnist)

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Aha!

Submitted by Chris Chiesa on January 29, 2010 - 9:59 P.M.

Brett, thanks for your comments regarding the _intentional_ incompatibility of Intel Centrino and Intersil Prism Wifi chips. I'm trying to write a school paper on Wifi incompatibility and this is the first writing I've seen by someone who actually seems to know something believably detailed. I'd been wondering whether something like this -- i.e. deliberate technical sabotage driven by corporate greed -- were a factor, but had been telling myself that I was just being cynical and that my cynicism had no place in a technically-oriented paper. Now I have a leg to stand on, to include it.

Is there any way to tell _which_ laptops, wifi cards/devices, routers, etc., use which set of chips? I ask because my home equipment is old enough to possibly still be using Prism, or even some third party product which might pre-date BOTH.

At one point, I had a situation at home in which Laptop A would communicate with Router A but not Router B, and Laptop B would communicate with Router B but not Router A -- and have been driving myself crazy with various theories as to WHY. I'm also surprised that if the incompatibilities can be fixed by modifying drivers, nobody has popped up and simply done a "grassroots" driver fix. SOMEBODY is writing drivers for, say, Linux, so there are people out there who know how to write drivers AND know how the various chips work... Anyway, thanks for your comment.

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