Yeah, the best you can expect is 6 dBi of gain. That is what I was trying to say earlier when I suggested a monster 15dBi antenna. The difference between 2.2dBi and 9 dBi is about 6dB, so that is why that is max gain you can expect.
Small buildings? Print out of the floor plan, a pencil with eraser and something to measure signal. Just use the "live" site survey technique. Get ansmall cart with a mono pod, power source (UPS will work) and an AP. Find the first good location of the AP, I like to start in the corner. Walk the location with your laptop and find where the acceptable signal ends. Mark that on your paper. Move the AP and repeat. Overlap signals as required (more discussion). Rinse. Repeat.
thanks for all the help GT..I'll probably head to that site in November at some point...Hopefully those antennas help those few computers on the fringe of coverage..If not, I'm not sure what to do...Don't have much options in terms of moving the WAP...Site surveys were never done for these sites, they just put the waps in the mechanical room with the rest of the telecom equipement so they didn't have to run wires...Most of the sites work fine, just this one in particular has poor coverage for some reason.....
just got back from the site today and all seems to be well now....It appears the problem was a Xray room. I guess those walls are made of led or something because nothing would go through it or around it....I had to rewire the access point and put it in the hallway so it had straight shot at the other end of the building..I also slapped a cisco 1242ag repeater in the mix and they now have internet at the residence building across the street..
thanks to all who helped me out and thankfully I'm studying the CWNP stuff or there's no way I could have done this..I'm still a newb but making progress..