Variables play into how well wireless works

Aug 28, 2009 By Anne Krishnan

In a recent column, Dianne Dunlap, a customer support engineer specializing in wireless technology for Cisco Systems, gave a thorough breakdown of how to check whether wireless Internet connectivity problems are due to wireless card issues -- and how to fix them.

This week, she's digging into how to identify and remedy potential problems with your wireless network.

Readers often report that their computers have different connectivity in different parts of the house. That's not uncommon, Dunlap said, due to factors such as the quality of the card and its ability to discriminate between noise and good signal; interference from other wireless equipment; and non-wireless interference in one location but not another.

There are two wireless bands -- 2.4 GHz and 5 GHz; within the bands are channels. Some network interface cards (NIC or wireless cards) and access points can access both 2.4 GHz and 5 GHz reception. Some wireless cards and access points can only transmit/receive one band, leaving you out of luck if they're incompatible.

The analogy would be AM and FM radio, Dunlap said. Your AM radio receiver cannot receive FM stations; conversely an FM receiver cannot receive AM stations. But some radios can tune into both AM and FM stations.

To see what (including yours) are operating in your area, go to "Start," "Control Panel" and "Network Connections." You may need to click on "View Wireless Connections."

If you are using software provided by your wireless card vendor to manage the card, it should show you similar information, but may provide more detail such as the channels that the different networks are using.

The channels in use are of interest, because there can be conflict if neighboring wireless access points are on the same or nearby channels. On the 2.4 GHz band, which is more susceptible to interference, both your access point and your neighbors' points should be set for channels 1, 6 or 11. If you have the 5 GHz band, the channel selection is less critical because more channels are available.

In addition to having your neighbors on a competing channel, there also are many other sources of interference on the 2.4 GHz band, including cordless phones, garage door openers, baby monitors, microwaves, video surveillance cameras and wireless audio equipment. Microwaves typically cause interference on the higher channels.

Signal quality also is important. Even though wireless transmissions might start at the router's highest rate (from 11 Mb/sec for an older B access point to 300 Mb for the newest N routers), when signal quality is poor -- if the PC is in the vicinity of a microwave, perhaps -- the data rates may later be negotiated down to a lower rate to keep the traffic going.

Furthermore, while older network cards theoretically should work fine with newer access points, this may not be the case if the card's hardware or drivers are poor. If your card cannot perform at the faster rate and your rates are configurable, you might want to see if turning off the higher data rates on the access point makes the connection more stable.

Mounting of the access point can also be an issue. If it has omni-directional antennas (usually 3-4" long), the beam pattern is like a doughnut with the antenna going through the doughnut hole. Omni antennas should be mounted vertically, not horizontally.

Finally, some service providers anticipate that they are servicing one device at a time, e.g., if there are multiple PCs at a site, only the first PC to boot will be able to get an IP address and access the Internet. This possibility can be ruled out by powering off the other PCs and rebooting the service provider's equipment so that the problem PC is the only PC it sees. If the problem PC reliably works when it is the only PC, then the issue would be with this limitation from the service provider.
___

(c) 2009, The News & Observer (Raleigh, N.C.).
Visit The News & Observer online at www.newsobserver.com/
Distributed by McClatchy-Tribune Information Services.

Explore further: FTC says AT&T misled customers with unlimited data

add to favorites email to friend print save as pdf

Related Stories

Likely culprits to check when wireless connection crawls

Aug 14, 2009

Q: I have a problem with our Dell laptop computer's wireless connection using Internet Explorer. At various times, the speed drops down to sloth and then stops altogether. At the same time, other computers, a desktop connected ...

NIST Measures Challenges for Wireless in Factories

Aug 31, 2007

Factories have much to gain from wireless technology, such as robot control, RFID tag monitoring, and local-area network (LAN) communications. Wireless systems can cost less and offer more flexibility than cabled systems. ...

Netgear Gears Wireless Switch to SMBs

May 22, 2007

Netgear is announcing at Interop here a fully featured wireless controller that's designed to meet the wireless infrastructure needs of a small to midsize enterprise.

Conflicting signals can confuse rescue robots

Mar 02, 2007

Sensor-laden robots capable of vital search and rescue missions at disaster sites are no figment of a science fiction writer's imagination. Prototypes and commercial models of urban search and rescue (US&R) robots will soon ...

Recommended for you

Preparing for a zero-emission urban bus system

47 minutes ago

In order to create a competitive and sustainable transport system, the EU must look to alternative fuels to replace or complement petrol and diesel. Not only will this reduce transport emissions but it will ...

Lenovo wraps up purchase of Motorola phone unit

1 hour ago

Lenovo Group announced the completion of its acquisition of Motorola Mobility from Google Inc. on Thursday in a move aimed at making the Chinese computer maker a global smartphone brand.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

frajo
1 / 5 (1) Sep 02, 2009
To see what wireless networks (including yours) are operating in your area, go to "Start," "Control Panel" and "Network Connections."

Doesn't he know the secret of "the Start button" or does he want the readers not to know?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.