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2.4Ghz Wi-Fi Channel Selection

This Tutorial addresses:
2.4 Ghz Wi-Fi Channel Picking

Pre-requisites
[_] Wi-Fi Access Point or Wireless Router using 2.4 Ghz 802.11\b\g\n
[_] Laptop with Wi-Fi adapter

Channel Selection
The follow is meant to make selecting a channel for your Wi-Fi network easier, and give you some basic information pertaining to channel selection.

Channel selection for 2.4 Ghz frequencies seems to be something that is either very easy or exceptionally difficult. If you live in the middle of a green field, you can pick just about any channel you want, but when it comes to metro areas where you might have dozens of neighbors channel selection can become something of a dark art. But here are a couple of simple tips that may help you pick the best channel for your situation:

1. The first step whenever setting up a wireless network is to determine what is around you. It is beyond the specific scope of this guide, but there are many free software tools that will locate Wi-Fi AP's around you and give explicit details about them.(Chanalyzer from MetaGeek works well)

2. Channels that are within 3 positions of one another overlap (for example channels 1 and 5 overlap, but channels 1 and 6 do not.) Overlap is BAD. When a channel overlaps another you may lose the ability to transmit data on the portions of the channels that overlap, this has a decidedly negative impact on performance. (Think about a giant truck merging into your lane, your going to get out of its way, and as for your data it's gone.)[Performance degradation happens primarily if both you and your neighbor are using your Wi-Fi heavily, normal usage won't notice as large of an impact.]

3. The most common channel reuse pattern for 2.4 Ghz is to use channels 1, 6, and 11. These channels don't overlap, you could have one Access Point on each channel and they would not effect each other. This is the preferred channeling for businesses installing multiple AP's.

4. Now here is the interesting part: Overlap is bad right; But only when you are using different channels. When two or more access point are on the same channel they become aware of one another, they can see each other, when they are on offset overlapping channels they can't. (for example: 2 access points on the same channel can work out when to transmit together, 2 AP's on different channels don't see each other and they'll step on each others toes slowing down their transfers extensively.)

Scenarios
Channels 1 and 6 are in use: Channel 11 would be your optimum choice as it won't overlap the other two channels.

Channels 1, 6, and 11 are in use: Overlapping one of the channels completely could be your best bet.

Channels 1, 6, and 9 are in use: Using channel 11 should be your best choice as this has the least amount of overlap.

Channels 2, and 10 are in use: Using channel 6 may give you the overall best throughput. But using 2 or 10 may also give you good results.


*The image above shows a representation of what channels overlap and where, if possible you will want to move to a channel that is not overlapped by your neighbors.(Only shows channels 1-11 for the United States, channels 12 and 13 may be available in your area and follow the same pattern as 1-11.)

Wrap Up
Making the decision between overlapping and offset channels usage can be tricky. If your neighbors have normal low end usage, overlapping or even offsetting won't cause to much of an issue for you. But if you have a bunch of power users nearby, who use their wireless consistently and heavily, no other options are available to you so overlapping completely is ideal.

*If you do live in a metro area with a lot of 2.4 Ghz wireless devices in your area consider upgrading to 5 Ghz technology using 802.11a\n\ac. The 5 Ghz. frequency ranges do not automatically suffer from channel overlap, there are many more channels available, and far fewer home devices that effect them (Microwaves, baby monitors, even phones can corrupt Wi-Fi transmissions.)

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