When shopping for a wireless lan antenna it is important to know that there are some things that will help you achieve a good outcome. I have done some testing on various antennas and many do not work well at all. Most overestimate the gain of the antenna by saying it is 9db rather than say 4.5 or similar.All the gain figure tells you is how much signal is going in a particulat plane. I will explain, the signal from an antenna resembles a dohgnut in shape, when the gain of an antenna increases it means that the top and bottom of the dohgnut is being reduced but the middle is becoming stronger. If you wanted to have a wireless connection in a 2 storey house and the router and say laptop where on different floors then a low gain antenna would work better as it is not concentrating the signal at right angles to the antenna.The other antenna types are directional antennas that concentrate all the signal energy in one direction, this is good when you have a fixed system and do not need general area coverage. Also make sure that all antennas are vertical as a mismatch causes signal loss. The biggest problem that I have seen is that a lot of antennas get supplied with really thin cable, this stuff is lossy and should be avoided, use thicker cable to get more signal strength. To get good reception use short lengths of cable to keep losses down, use a 6dbi-9dbi antenna for general coverage,keep the antenna away from all objects as these attenuate the signal. Make sure to use the WEP security settings on your wireless connection or else you may get free loaderd using your net connection