The short answer is "Yes, it does."
The hitch is, like anything else, there's a tradeoff: gain versus "pattern."
An isotropic radiator is a theoretical thing: it represents a single point of radiation ... if it was in a sphere, it would illuminate every point of the interior of the sphere evenly. It is used strictly as a value of comparison (the "i" in dbi).
As you begin to form the signal into higher-gain configurations, the pattern of illumination is deformed (all that "extra power" has to come from somewhere .... it comes from "stealing" it from another part of the pattern).
In the case of a dipole, the pattern (from above)looks sort of like a two-bladed propeller, where the "blades" are the increased signal (both transmit and receive).
In the case of a Yagi, the signal is reflected and focused (by two different kinds of elements) into a long single lobe (there are some smaller back lobes, but they are generally insignificant). The higher the gain, the longer (but thinner) the lobe (remember, the "power" has to come from somewhere).
For a parabolic dish, the single lobe is the longest (but also the thinnest, see above) and it tends to have the least back-end (behind the antenna) secondary lobes.
For a "stick" antenna (omnidirectional pole) with gain, the "stolen" power comes from the ends of the antenna (each tip). There are a number of configurations that will provide some gain ... unfortunatly, the pattern is frequently *not* a nice desirable "donut" shape with the sick in the middle of the hole.
The physics are such that sticks with gain tend to radiate in more of a cone shape, with the larger diameter of the cone towards the top of the stick (towards the sky) ... the more gain (generally speaking, depending on the type of stick) the more skyward is the radiation pattern.
There's some fairly complex generation and propagation stuff that explains this, more than I can describe.
The bottom line: before buying an antenna, especially a stick antenna, find a diagram that describes the pattern ... if you can't find one, chances are you won't want to gamble on whether it'll work well for you.
Look for a diagram (there'll be two actually, one from the "side," one from above): compare it to the way you intend to deploy your system ... look at the side diagram to see what the lateral coverage will be, and look at the "from above" diagram to see if the pattern is basically a circle.
At the least, if you know the pattern, you can deploy your APs and / or antennas to maximize the power (and reception) gain for the antennas you've chosen.
I hope you've found this information useful. The restricted space (and my knowledge of the details) means that the standard disclaimer applies: "Some information has been bent, folded, spindled, or mutilated for the sake of clarity and brevity"
Good Luck
Scott
