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Royston posted this in Networking on December 16th, 2009

What to Look For in Wireless networking: Range, Speed and Standards.

What to Look For in Wireless networking: Range, Speed and Standards.

Not sure what you’re doing in your wireless card shopping? Want to make sure you’re buying the right thing but just have no idea what it is you’re looking for? Well, you’ve come to the right place. When you’re looking to buy a wireless network card, I can tell you right now that you’re looking at three key issues: range, speed, and standards.

A Typical Specification.

This is a typical specification for a Linksys wireless PCMCIA laptop card:

11 Mbps high-speed transfer rate; interoperable with IEEE 802.11b (DSSS) 2.4Ghz-compliant equipment; plug-and-play operation provides easy set up; long operating range (up to 120m indoor); advanced power management features conserve valuable notebook PC battery life; rugged metal design with integrated antenna; compatible with virtually all major operating systems; works with all standard Internet applications; automatic load balancing and scale back; model no. WPC11. (source: amazon.com).

Now, some of those things can be pretty much ignored. Really, ‘virtually all major operating systems’? That means nothing. The reason I’ve put it here, though, is so you can see which things are important to keep an eye out for.

Range.

See where it says ‘up to 120m indoor’? This tells you that the maximum range of the wireless card you’re looking at is 120 metres — that’s what it would be if everything was perfect. In practice, thick walls and interference can reduce this number by as much as 90%.

Without enough range, your wireless network is going to be pretty useless. It’s not much fun having no wires when you have to keep all the computers in the same room to get them to connect to each other.

As a rule of thumb, unless your walls are made of drywall or wood, it’s best to buy about four times the strength you’d think you’d need. Even in perfect conditions, get twice as much, to be safe. If you need to convert from metric to imperial units, remember that there are 30 centimetres (0.3 metres) in a foot and about 2.5 centimetres in an inch — you shouldn’t have too much trouble.

Speed.

Do you see where it says ‘Mbps’ in that description? That number is the speed of the wireless connection. 11 Mbps is about one and a half megabytes per second — to convert megabits (Mb) to megabytes (MB), just divide by eight. 802.11b wireless cards all have a speed of 11Mbps, while 802.11g ones run at 54Mbps — the next generation will be even faster.

Speed is important to your wireless network because it’s going to directly influence how long you have to wait for things like files to transfer from one computer on the network to the other. It is less important for Internet use, however, because there are currently very few Internet connections running at speeds over 11Mbps — it’s really as much as you need, at least for now.

Standards.

Somewhere in the specification of what you’re looking at, you should see the number ’802.11′, followed by a letter ‘a’, ‘b’ or ‘g’. This is the standard that the wireless device conforms to, and tells you whether you will be able to use it with your other wireless devices.

Basically, 802.11b and 802.11g are compatible with each other. 802.11a is not compatible with either and is quite a bad standard all round, so you shouldn’t buy 802.11a. Out of b and g, b is cheaper but slower, while g is more expensive but faster. It’s worth considering that adding a b-speed device to a network that has g-speed devices will often slow the whole network down to b-speed, making the g-devices pointless.

If your wireless device doesn’t conform to the right standards, it’s not going to be much good to you. I often see naive people bidding for used wireless equipment on eBay, not realising that it’s going to be terribly slow and not work with any other equipment they might have. Always make sure that you check what standard the wireless equipment is — if you don’t know the 802.11 letter, don’t buy it!

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