In The Beginning...

When it first started shipping in Spring 2002, 802.11a equipment was poised for big things, since it seemed to hit all the right buttons for Enterprise buyers, at least. First, it really did have about five times the best-case throughput of 802.11b products, although the typical equipment clocked at about 24-25Mbps vs. the advertised 54Mbps raw data rate. And second, all products operated on eight non-interfering channels in the 5GHz band, with some products offering five additional "high-band" channels. This not only moved WLAN activity to a less crowded and more interference-free part of the radio spectrum to improve reliability, but greatly simplified multiple Access Point installations.

The excitement seemed short-lived, however. Products were significantly more expensive than their 802.11b counterparts, but more importantly, didn't deliver all that they promised. Review after review praised 11a products for their best-case speed, but complained that the products' effective range wasn't as great as that of 802.11b products'. Figures 1 through 3 below show typical results from my reviews of first-generation 11a products.

Figure 1: Linksys WAP51AB and WPC54A 802.11a throughput
(click on the image for a full-sized view)

Figure 2: NETGEAR HE102 and HA501 802.11a throughput
(click on the image for a full-sized view)

Figure 3: SMC 2755W and 2735W 802.11a throughput
(click on the image for a full-sized view)

In each plot, you can clearly see a significant difference in throughput between the close-range Condition 1 and 2 tests, and the longer-range tests under Condition 3 and 4. (See this page for a description of the test methodology and test conditions.)

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