After setting up a couple of access points to cover our campus, and a crash course in WEP, MAC filtering, and closed networks, our fledgling 802.11b network was up. With relatively little effort and expense (about $3000 and a few hours work in all), we now had seamless coverage in all three of our buildings, complete with roaming between APs. At the time, the main O'Reilly offices in Sebastopol consisted of three two-story buildings, covering an area about 450 by 150 feet. Using one Lucent AP-1000 in each building, and a small 5db omni at each AP, I was able to cover nearly all of the offices and conference rooms.
Early on in the process, one of our users noticed that she couldn't get online, even though she had a very strong signal. Upon checking her network settings, I realized that she hadn't set her ESSID, and was therefore associating with any available network. It just so happened that the network with the strongest signal was coming from the business next door! I fired up Lucent's Site Map tool, and, sure enough, there was an existing 802.11b network immediately next door. After a quick conversation with their sysadmin, we decided on a channel numbering scheme that would minimize interference between the two networks. (This is exactly why a preliminary site survey is so important: even though you may not see antennas, a network may already exist in your area! Don't just assume that since wireless is new to you, it's new to your part of town.)
Now that our offices were saturated with access, with 50+ users up and happily untethered, what could we do with it next? Naturally, more than a few eyes turned to the hotel and coffee shop across the street. If one could get a signal from the hotel, then visiting employees who stayed there could get online for free, at 11Mbps (as opposed to paying per minute for a trickle of dialup access). And of course, being able to work directly from the coffee shop must do something for productivity. With visions of mochas and bandwidth dancing in my head, I looked into adding external antennas to increase our range.