Datastream Cowboys

Here are the basics about 802.11. There are 13 channels 1 to 13, however depending on your location depends on which ones you have. In the US and Canada they have 1 to 11, but in Japan they have all 13 and in France they have only 10 to 13. The 2.4 GHz wavelength is 4.775 in (12.128 cm) to 4.893 in (12.429 cm). You will see antennas reference 4 wavelength or 8 wavelength. This just means that the antenna length is whatever times 4.83 inches long.

Channel	Frequency	Wavelength				ETSI
	(MHz)	cm	in
1	2412	12.429	4.893	X	X	X	X
2	2417	12.403	4.883	X	X	X	X
3	2422	12.378	4.873	X	X	X	X
4	2427	12.352	4.863	X	X	X	X
5	2432	12.327	4.853	X	X	X	X
6	2437	12.302	4.843	X	X	X	X
7	2442	12.277	4.833	X	X	X	X
8	2447	12.251	4.823	X	X	X	X
9	2452	12.226	4.814	X	X	X	X
10	2457	12.202	4.804	X	X	X	X	X
11	2462	12.177	4.794	X	X	X	X	X
12	2467	12.152	4.784			X	X	X
13	2472	12.128	4.775			X	X	X

There are many types of antennas but only to classes directional and omnidirectional. Directional antennas are just as the name implies it's directional. The other type omnidirectional is just like your radio antenna on your car or the little factory antenna on your wireless access point (unless you have an apple airport). For antenna design I use the center frequency of the operating range to find this you use the following formula:

center frequency = (lowest frequency + highest frequency) / 2
center frequency = (2.400 + 2.462) / 2
center frequency = 4.862 / 2
center frequency = 2.431 GHz