In 2000, 802.11b became the standard wireless ethernet networking technology for both business and home. The WiFI organization was created to ensure interoperability between 802.11b products. With a realistic throughput of 2.5-4Mbps, it is fast enough for most network applications and tolerable for file transfers.

Do I need an access point?

An 802.11b wireless network adapter can operate in two modes, Ad-Hoc and Infrastructure.

Infrastructure mode:

All your traffic passes through a wireless ‘access point’.

Ad-hoc mode:

Your computers talk directly to each other and do not need an access point at all.

Access point varieties

Access points come in three varieties -- bridge, NAT router and NAT router+bridge. A bridge type connects a wireless network to a wired network transparently. Communication is possible between both networks in both directions. A NAT router type routes traffic from your wireless network to an Ethernet wired network, but it will not route traffic back. This type can be used to share an Internet connection. Lastly, there are hybrid NAT router + Bridge devices that bridge your wired and wireless networks, then route them both to the internet using a single IP address. This is good for sharing an Internet connection when you have both wired and wireless computers in your home. These are often called Cable/dsl routers with wireless .

Security

Any network adapter coming within range of another 802.11b network adapter or access point can instantly connect and join the network unless WEP – wireless encryption protocol – is enabled. WEP is secure enough for most homes and business’ but don’t think it can’t be hacked. There are several flaws in WEP  making it unusable for high security applications. At this point, it takes some serious hacking abilities to bust into a WEP enabled network so home users should not worry.

WEP and Speed

WEP ‘WILL’ slow down your wireless network. Expect a 20-50% reduction in speed depending on the products you are using. The speed issue is often the result of an access point without enough processing power.

Encryption keys

Encryption comes in 64bit and 128bit key varieties. All your nodes must be at the same encryption level with the same key to operate. 40bit and 64bit encryption is the same thing; it’s just a matter of how the manufacturer decided to label the product. Often 128bit cards can often be placed in 40/64bit mode. (FAQ info on keys)

NIC Form Factors

802.11b adapters come in two major form factors. PCCards for laptops and USB for desktops. In addition, there are PCI adapters that let you plug a PCCard into a PCI Slot. PCI slot adapters are often finicky about working correctly in anything but Windows 98/SE/ME. I would opt for the USB version to play it safe if you have Windows XP or 2000 on a desktop machine.

How fast is it in the real world

A full strength 802.11b signal will get you about 3.5-4.5 Mbps without WEP enabled. With WEP enabled, expect 2.5-3.5 Mbps. As you put walls and distance between your wireless adapter and your access point, your speed will drop. Don’t expect to put more than a few walls between you and your access point. (click here for network speeds explained)

Technical

802.11b is a half duplex protocol – it can send OR revive, but not both at the same time. In addition it uses the same 2.4 GHz range as many cordless phones so plenty of opportunity exists for interference. Use 900Mhz cordless phones if using 802.11b in the same area.

Changing the antennas on a dual AP

You can change the antennas on a dual AP but it will not work like you might think. Your AP has "diversity antennas". Essentially diversity antennas are designed to allow better coverage under the assumption that one of the two antennae will be in a better position. To be effective, both antennas need to be the same and located relatively close to each other. Also if you have a Linksys router with updated firmware, you can select only the right or left antenna to be active, or disable diversity spread altogether, and divide the power between the antennas.(left is left when standing behind it, not looking at it). 

Diversity is most often present in AP units but some client cards also have diversity. In client cards, diversity is only partially implemented by the chipset. For example, the Prism chipset only uses diversity when receiving. For transmitting, the Prism chipset directs output to one of the antenna and never chooses the other. So, if one of the antenna is highly different, you might get unexpected results with a Prism chipset

Extended Range

Antenna selection has a tremendous impact on the range of your wireless network. Here a few practical things:

So in short, while they're billed for 11 Mbps, your mileage will most certainly vary. The most I've been able to squeeze through a card doing WEP was about 6.5 Mbps sustained (roughly 8 Mbps without WEP), and even that was downhill with a good, stiff tailwind.

Lay your antennas in the spring and summer.  Well, your worst natural enemy is water. Low-power microwaves will bounce off leaves like a mirror. If you set up a well-placed antenna in the winter, you will be horribly disappointed in April when the trees are blooming and your signal is dropping.