Networking / Beginners

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Placing Access Point

The optimal location for an access point depends on the area you want to cover and whether or not you care if the signal bleeds out beyond the borders. You also need to use antennae that provide enough signal and push that signal in the proper direction.

Omni-directional and Centered For a typical network, you want blanket coverage and would place a WAP with an omni-directional antenna in the center of the area. With an omni-directional antenna, the radio wave flows outward from the WAP. This has the advantage of ease of use-anything within the signal radius can potentially access the network. Most wireless networks use this combination, especially in the consumer space. The standard straight-wire antennae that provide most omni-directional function are called dipole antennae.

The omni-directional and centered approach does not work for every network, for three reasons. First, if the signal exceeds the size of the network space, that signal bleeds out. The signal can bleed out a lot in some cases, particularly if your specific space doesn't allow you to put the WAP in the center, but rather off-center. This presents a security risk, because someone outside your network space could lurk, pick up the signal, and run software to try to hack into your network. Or, a hacker might use your wireless signal for purposes that you might not condone. Second, if your network space exceeds the signal of your WAP, you'll need to get some sort of signal booster (see "Gaining Gain," below). Third, any obstacles will produce glaring dead spots in network coverage. Too many dead spots make a less-than-ideal solution. To address these issues you might need to go to other solutions.

Gaining Gain An antenna strengthens and focuses the radio frequency (RF) output from a WAP. The ratio of increase-what's called gain-is measured in decibels (dB). The gain from a typical WAP is 2 dB, enough to cover a reasonable area but not a very large room. To increase that signal requires a bigger antenna. Many WAPs have removable antennae that you can replace. To increase the signal in an omni-directional and centered setup, simply replace the factory antennae with one or more bigger antennae. Get a big enough antenna and you can crank it all the way up to 11!

Focusing the Wave When you don't necessarily want to broadcast to the world, you can use one or more directional antennae to create a nicely focused network. A directional antenna, as the name implies, focuses a radio wave into a beam of sorts. Directional antennae come in a variety of flavors, such as parabolic, dish, and Yagi, to name a just a few. A parabolic antenna looks like a satellite dish. A Yagi antenna (named for one of its Japanese inventors) is often called a beam antenna and can enable a focused radio wave to travel a long way, miles even.

NOTE Patch antennae are flat, plate-shaped antennae that generate a halfsphere beam. Patch antennas are always placed on walls. The half-sphere is perfect for indoor offices where you want to fill the room with a strong signal but not broadcast to the room behind the patch.