WiFi router antennae

https://dl.dropboxusercontent.com/u/1597869/photo 1.JPG

Is the active part of this antenna the full height of the tube?

It looks like this reflector isn't doing much unless the active part is just
the tip!

 

El 10-11-13 1:23, Mike Cook escribió:

Hello,

I can't determine the size of the antenna, but assumming it is between
a half-wave and full-wave radiator for 2.45 GHz, you are right: it
doesn't act as a reflector. It just detunes the antenna.

It also looks like the "reflector" is too close to the antenna. Even
if it would be large enough to function as a reflector, it will not
help much as it completely detunes the antenna.

I am not aware of antennas that do both 2.45 and 5.8 GHz where the 5.8
GHz radiator is only in the tip of the antenna.

 

Doesn't look to me that the "reflector" is doing anything one might expect.
What is it supposed to be doing?

bill