IEEE 802.11b (Wi-Fi) uses DSSS, using 22 MHz of bandwidth (passband) to transmit data with speeds of up to 11 Mb/sec. A Wi-Fi system can use any of 13 22-MHz-wide sub-channels across the allocated 83.5 MHz of the 2.4 GHz frequency band, however most equipment commonly available in Australia is designed for the 11 channel American market.



22 MHz wide Direct Sequence Spread Spectrum, 5 MHz channel spacing.

Channel       MHz

1                 2412 

2                 2417 

3                 2422

4                 2427

5                 2432

6                 2437

7                 2442

8                 2447

9                 2452

10                2457

11                2462

12                2467

13                2472



As such, there are only three non-overlapping channels: 1, 7 & 11.



(Source: Queensland Digital Group)