The 2.4GHz ISM Band.

Wireless networking systems using the 802.11b standard operate in the 2.4GHz ISM band. Other services, including microwave ovens, medical equipment, and cordless phones also operate in the ISM band.

Channel ID	US/Canada	Europe	France	Spain	Japan
1	2412	2412	-	-	2412
2	2417	2417	-	-	2417
3	2422	2422	-	-	2422
4	2427	2427	-	-	2427
5	2432	2432	-	-	2432
6	2437	2437	-	-	2437
7	2442	2442	-	-	2442
8	2447	2447	-	-	2447
9	2452	2452	-	-	2452
10	2457	2457	2457	2457	2457
11	2462	2462	2462	2462	2462
12	-	2467	2467	-	2467
13	-	2472	2472	-	2472
14	-	-	-	-	2484

A WLAN receiver can use any of these channels, and can automatically hop from channel to channel if interference is encountered. An 802.11b antenna for the US and Canada should radiate well between 2410 and 2460 MHz.