Wireless Channel Selection
IEEE 802.11 wireless nodes communicate with each other using radio frequency signals in the ISM (Industrial, Scientific, and Medical) band between 2.4 GHz and 2.5 GHz. Neighboring channels are
5 MHz apart. However, due to spread spectrum effect of the signals, a node sending signals using a particular channel will utilize frequency spectrum 12.5 MHz above and below the center channel frequency. As a result, two separate wireless networks using neighboring channels (for example, channel 1 and channel 2) in the same general vicinity will interfere with each other. Applying two channels that allow the maximum channel separation will decrease the amount of channel crosstalk, and provide a noticeable performance increase over networks with minimal channel separation.
Channel | Center | Frequency Spread |
| Frequency |
|
1 | 2412 MHz | 2399.5 MHz – 2424.5 MHz |
2 | 2417 MHz | 2404.5 MHz – 2429.5 MHz |
3 | 2422 MHz | 2409.5 MHz |
4 | 2427 MHz | 2414.5 MHz |
5 | 2432 MHz | 2419.5 MHz – 2444.5 MHz |
6 | 2437 MHz | 2424.5 MHz |
7 | 2442 MHz | 2429.5 MHz |
8 | 2447 MHz | 2434.5 MHz – 2459.5 MHz |
9 | 2452 MHz | 2439.5 MHz |
10 | 2457 MHz | 2444.5 MHz |
11 | 2462 MHz | 2449.5 MHz – 2474.5 MHz |
12 | 2467 MHz | 2454.5 MHz – 2479.5 MHz |
13 | 2472 MHz | 2459.5 MHz – 2484.5 MHz |
Note: The available channels supported by the wireless products in various countries are different. For example, Channel 1 to 11 are supported in the U.S. and Canada, and Channel 1 to 13 are supported in Europe and Australia.
The preferred channel separation between the channels in neighboring wireless networks is 25 MHz (5 channels). This means that you can apply up to three different channels within your wireless network. There are only 11 usable wireless channels in the United States. It is recommended that you start using Channel 1, and grow to use Channel 6 and 11 when necessary.
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