Using your laptop to access a Wi-Fi network while on the road is usually as simple as finding an open network. The majority of notebooks now have wireless cards built in, and if yours doesn’t have one, you can easily add an inexpensive external wireless card. At home, creating and securing your own network is also simple.

Because wireless connectivity is so userfriendly these days, many people don’t actually understand how the connections are made or how they work. Knowing how everything works together is valuable, because you’ll have some insight as to how you can troubleshoot any wireless problems you may encounter.

The Wireless Radio
A wireless radio is a transmitter that resides on a wireless card. Many laptops have a wireless radio located somewhere inside the unit; however, some are built into cards that a user can plug into a PCI or ExpressCard slot on his laptop. The wireless radio’s job is simple: to transmit and receive radio signals. When these radio signals are transmitted from a network router to the chip in your computer, a Wi-Fi connection results, granting you access to the Internet via that connection.

There are two places on a laptop where you can find and manipulate your wireless radio. Your computer will have a switch for the wireless radio somewhere on the outside of the case, or it will be inside the computer, accessible only from the user interface when the computer is running. In either case, an indicator light on your laptop will show whether the wireless radio is on or off. Generally, this indicator will appear in a bank with other lighted gauges that give information about your system, such as battery power.

If your laptop has an external switch, turning the radio on and off is simple; just slide the switch to the desired position. If your laptop lacks an external switch, you’ll need to turn on your computer and locate the icon that represents the quality of your Wi-Fi reception on the System Tray at the bottom right of your display. Right-click the icon and select Disable Radio. A red X will appear over the icon, indicating that the radio is disabled. To enable the wireless radio, right-click the same
icon and select Enable Radio.

The Connection
A router transmits a network’s signal via radio waves. The wireless card in the computer receives the signal, which enables you to use the network’s bandwidth to access the Internet.

With an unsecured connection, any wireless radio within signal range can connect to the network; it’s a simple matter of sending and receiving radio waves. A secure connection uses encryption such as WEP (Wired Equivalent Privacy) or WPA (Wi-Fi Protected Access) to ensure that only users with an encryption key can access the network.

Connect With Windows XP/Vista
If your wireless radio is turned on, it will automatically search for available Wi-Fi networks when you boot your computer. Each time you connect to a network, WinXP adds it to your preferred list. You can adjust the order of preferred networks by clicking Start, Control Panel, and Network And Internet Connections. Click Network Connections, right-click Wireless Network Connection, and select Properties.

When the Properties dialog box appears, click the Wireless Networks tab and adjust the order of your preferred networks accordingly. For example, move your home network to the top of the list so your computer always looks to connect to that network first.

Vista computers operate in the same manner, with the exception that Vista’s Network And Sharing Center has more automated features to streamline connecting and troubleshooting.

Choose From Multiple Available Hotspots
When presented with a number of networks from which to choose, you should always choose the network that is most secure while offering the best reception. (If you’re at home, this would be your own secure network connection.)

When out and about, be on the lookout for evil twins, which are networks with official sounding names that have been set up by ne’er-do-wells in an attempt to pilfer information from you. For example, if you’re sitting in a coffee shop, look for the network with that establishment’s SSID, or name. It would be a good idea to ask for that information from an employee, a task you may need to take care of anyway to get a WEP or WPA password.

Troubleshoot A Connection
Because Wi-Fi operates on radio frequencies, interference can occur easily. Both 802.11b and 802.11g, the most commonly used Wi-Fi protocols, operate at 2.4GHz. Any appliance or device that operates at that frequency, such as a cordless phone or a microwave, can interfere with your Wi-Fi signal. To avoid this type of problem, position your computer as far away from such devices as possible.

If you’re getting a weak signal and you have a wireless adapter with an adjustable antenna, you can toy with the position of the computer and/or the antenna to get a better signal. Such devices also tend to get better reception than typical internal cards and external cards with no antenna.

There are a number of things that can cause a failed connection. If you’re attempting to connect to a network away from home, the list of possible culprits decreases significantly. Check whether your wireless radio is enabled or if there is an available network that is either open or for which you have an encryption key.

On your home network, any of the above solutions may work, but you also need to double-check your network to ensure the router is on. For all of your wireless networking devices, you’ll also want to make sure the drivers are up-to-date. Manufacturers routinely upgrade, update, or patch their products. If you don’t have the latest drivers installed, your gear may not work properly. Many companies will provide updates automatically, but if you’re having connection problems that you can’t solve, check the manufacturer’s Web site for any new drivers.

When all else fails, it never hurts to restart your computer and router. If you have an external card, remove it and firmly reinsert it before rebooting. A simple system reset solves many problems that otherwise might seem insurmountable.

Tags: Wi-Fi

This is continue of yesterday post.

Upgrade your base station

Routers that are based on the Draft N specification incorporate MIMO (multiple input, multiple output) antenna arrays. MIMO can improve range as well as speed. The Belkin Wireless G Plus MIMO Router released in 2007 use Draft N, and Belkin claims that the standard has twice the range of its predecessor. In the tests, range has improved a lots as other brand, such as Linksys and several other companies sell Draft N routers. Because those routers improve both transmission power and reception sensitivity, you can update just the gateway and continue using the older adapters on all your computers; the range of your network should still improve.

Add an antenna

You could also install a large, strong antenna on your base station so that it could blast out more-powerful signals. Many WiFi gateways have antennas that you can unscrew and replace with another antenna that produces a stronger signal. HyperLink Technologies has been selling antennas, and providing compatibility information about which gateways and wireless cards they work with, for years. The information is a bit technical, but it’s an exhaustive resource.

Apple has always kept its antennas inside the housing of its AirPort Base Stations; just a few of the 802.11g AirPort Extreme Base Stations came with an antenna jack for adding an external one. MacWireless has antennas, tools, and instructions for adding antennas to all AirPort models. MacWireless also offers a High Power 11g Access Point at $180. This unit has a regular-size antenna but a much more powerful radio, which provides more than 10 times the raw output power of most consumer gateways.

There is one downside to upgrading your antenna: while it can help your network, it can also mess up others. That’s because nearby networks may pick up your signals, and their performance will degrade as they try to cope with the barrage.

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WiFi networks can reach only so far.

The range of wireless equipment such as the radios and antennas that are built into consumer equipment such as the AirPort Extreme Base Station can vary from network to network, even minute to minute. But when one node of a WiFi network is too far from another, communications between the two break down, and your network doesn’t work.

While WiFi signals are supposed to reach 150 feet in any direction from a gateway, that optimistic figure is rarely reached indoors. One common cause is absorption. Building materials between two points can soak up so much of the signal that one device can’t detect another. Brick is particularly bad for WiFi because brick retains water, which readily absorbs WiFi signals.

As a result, a gateway that delivers a perfect high-speed connection to a laptop from 500 feet away when it has a direct line of sight might be invisible to a laptop that’s 50 feet away when there’s a brick wall between them.

There are two main indicators that your wireless network is having range problems. First, WiFi networks you know are there don’t show up in the wireless menu. Second, when you do connect to a network, the wireless icon in the system menu bar shows just one or two signal-strength bars and frequently slips to no bars.

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Wireless networking in Windows Vista has its own event log. All the events, whether informational, warnings, or errors, are written to an event log. From within Event Viewer, expand Application and Service Logs, expand Microsoft, expand Windows, expand WLAN-AutoConfig, and select the operational log.

This log is a great place to go when troubleshooting a wireless network problem if you need more information on what is happening.

Wireless networking is like a radio signal and as such is susceptible to the same problems. If you have a weak signal, you could have problems connecting to or staying connected to a wireless network. The following is a list of things to look for that could be causing a weak or no signal:


• The computer is too far away from an access point.
• There are a lot of walls between the system and the access point.
• There is electronic interference from another device such as a microwave or cordless phone.

To prevent these types of issues, always place WAPs in a central location away from devices that could interfere with the signal. Avoid placing your system near devices that could interfere. This may seem elementary, but these sorts of things are often overlooked when troubleshooting wireless problems.

You can troubleshoot the network components of wireless networking in Windows Vista in the same way that you troubleshoot a physical connection. All the same rules apply within the realm of wireless for IP address, DNS, DHCP, and so on. You will, however, have different issues that you may encounter during the initial establishment of the wireless connection.

If you are having a problem connecting to a wireless network, you must first look to these settings to isolate the problem:

SSID
If the SSID is broadcast by the wireless access point, it will be correctly configured in the connection settings. However, administrators often choose to not broadcast the SSID for security purposes. This means that you would have to know the SSID and enter it manually when setting up a connection to the wireless network. If this is the case, double-check the SSID that was entered during setup; if it is incorrect, you will be unable to communicate.

Security
You must be using the same type of security on the local system that is being used on the access point. An incorrect setting here means you will not be able to communicate with the network. If these settings are incorrect, you may see an error, in the Connect to a Network window that states the settings do not match.

Again, Windows Vista does a good job of matching these settings for a network it can see. If you manually set up the network or a user changes a setting, you will need to know what security type to configure in order to get the connection working. Additionally, the correct security type may be selected but another security setting may be incorrect. Also check to make sure that your passphrases, keys, and key indexes are correct where applicable.

WPA-Enterprise
If you are using WPA-Enterprise, remember that there is an authentication server of some type in the mix. Make sure that the user can connect to the server and that the firewall isn’t blocking this access. In addition, with WPA-Enterprise, you can use certificates for authentication.

Wireless networking has come on strong in the past few years. Wireless networking is defined by the IEEE 802.11 standard. Also known as Wi-Fi, 802.11 comes in three flavors: a, b, and g. The differences relate mainly to the operating frequency and the available bandwidth.

To utilize wireless networking in a permanent setting where a wireless network needs to exist full time, you need both a Wireless Access Point (WAP) and a wireless NIC in each computer. A wireless network that uses a WAP is known as an infrastructure network. All the devices must support the same standard of Wi-Fi; in other words, 802.11b NICs can only talk with 802.11b access points. It is not uncommon to find WAPs and wireless NICs that support multiple standards. When running in infrastructure mode, the WAP is hard-wired to the physical network. All wireless clients must connect to a WAP in order to communicate with other wired and wireless devices.

You can also create an ad hoc network using 802.11 wireless NICs. In an ad hoc network, several machines with wireless cards can communicate with one another without the use of an access point. Each machine in effect acts as both an access point and as a client. Ad hoc networks are great for small meetings or for transferring large files from one machine to another in an area where a network connection is unavailable.

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