There are a couple of ways to do that, but you may want to rethink your distance.
1) You can lower the transmit power setting on the AP. However, it may be unintentionally increased later by accident or by someone else. OR 1a. You can force loss on the line between the AP and the antenna by inserting an attenuator, but that will also drop the Receive strength, so you would only want to do that with separate TX and RX antennas.
2) You can use a cable and antenna config that results in the final signal strength you want. For 7m to a user with a PCMCIA card and decent reliability, you want final output of about -12dBm. That would mean setting the AP to 11Mbps only at 1mW and putting the 2.2dBi antenna on the end of about 200 feet of cable. 2b) or set the AP to 1mW, 11Mbps only and put a 13dB antennuator in line to the antenna.
7 meters is a very short range. In fact, that's too smal an area to get enough people to max out capacity on the AP. We can help you with coverage layout and design based on user capacity without interference problems.
Matthew Wheeler
Chief Wireless Architect
www.BlueModal.com
