Let me be the first to say it: 802.11a stinks for all practical purposes.
The wireless networking standard for 54M-bps bandwidth in the 5GHz range started slowly, gained momentum slowly and is now on its way out. At least, thats what Steve Jobs said in his Macworld keynote earlier this month. Thats why Jobs is bypassing 802.11a and installing 802.11g radios (aka Airport Extreme) in Apples new Macs.
Hes partially right. 802.11a is terrible for consumers. It has a practical range of 60 feet, far less than its theoretical range of 300-plus feet. And if the structure youre using it in has walls, the range is cut to about 5 feet. Theoretically, you can install some flashing and bounce your signals around to get an extra 5 feet, but at some point, it becomes easier to run cables. Especially when you realize how rapidly 802.11a performance degrades over distance.
The problem with 802.11a is that a visionary company called Atheros was the only chip-set provider for 802.11a for so long that it couldnt ramp prices down fast enough to generate consumer interest, which would have led to better antennas and chip-set design. Other companies sat around waiting to see if it would take off. The other problem is that 802.11as RF is based on OFDM (orthogonal frequency division multiplexing), which is more complex than the spread-spectrum technology used in 802.11b radios. That means its more difficult to package.
But heres where Jobs is wrong: 802.11g suffers from many of the same problems as 802.11a, and has a few more. 802.11g was hung up in the IEEE even longer than 802.11b or 802.11a. Its also based on OFDM. It runs in the 2.4GHz space, which theoretically can run interference on your network. Sure, its compatible with 802.11b, but with low-cost dual 802.11a/b units coming, does that matter? 802.11a has a chance because its better designed for offices with a lot of clustered systems, whereas 802.11b and 802.11g would barely work because there are few overlapping channels available.
Really, though, its all about cost. Whichever one costs less than $100 for an access point and a couple of cards will win. In most homes, 802.11b is good enough—that is, until cable and satellite companies figure out how to start broadcasting to the PC.
Which one will you be installing? Write to me at firstname.lastname@example.org.