NETGEAR WG511U user manual 802.11a Legal Power Output and Wireless Channels

User’s Manual for the NETGEAR Double 108 Mbps Wireless PC Card 32-bit CardBus WG511U

Note: The available channels supported by the wireless products in various countries are different. For example, Channels 1 to 11 are supported in the U.S. and Canada, and Channels 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, as these three channels do not overlap.

802.11a Legal Power Output and Wireless Channels

IEEE 802.11a utilizes 300 MHz of bandwidth in the 5 GHz Unlicensed National Information Infrastructure (U-NII) band. Though the lower 200 MHz is physically contiguous, the FCC has divided the total 300 MHz into three distinct domains, each with a different legal maximum power output. Below is a table of summary for different regulatory domains.

Table B-2:	802.11a Radio Frequency Channels
U-NII Band		Low	Middle	High
Frequency (GHz)		5.15 – 5.25	5.25 – 5.35	5.725 – 5.825
Max. Power Output		• 50 mW for US	• 250 mW for US	• 1 W for US and Australia
		• 200 mW for Canada,	• 200 mW for Europe and	• 4 W for Canada
		Europe, and Australia	Australia	• 25 mW for Europe
			• 1 W for Canada

Note: Please check your local Authority for updated information on the available frequency and maximum power output.

IEEE 802.11a uses Orthogonal Frequency Division Multiplexing (OFDM), a new encoding scheme that offers certain benefits over a spread spectrum in channel availability and data rate. The 802.11a uses OFDM to define a total of 8 non-overlapping 200 MHz channels across the 2 lower bands; each of these is divided into 52 sub carriers and each carrier is approximately 300 KHz wide.

B-4 Wireless Networking Basics

August 2004