wireless variables

[bealzz]

Just a couple of quick questions about different aspects of wireless.

With some of the routers ive looked at you have the option to crank up the power... this got me thinking.

1. Cranking up power does what? Increases range but adds more noise?

2. Do larger anntenas allow you to crank the power without as much noise as say a small anntena?

3. Why are higher dbi anntenas better than lower ones?

Ive read up on some of it, but there are still some unanswered questions out there.

 

[QwertyJuan]

1. Cranking up power will increase your range. Noise? Never really noticed much difference in lag or whatever, if that is what you mean.

2. Larger antennas give you more range. Have a few here, and they really did make a difference over stock.

3. Why are they better?? Not sure on all the technicalities, but isn't bigger always better??

QJ

 

[Rix2357]

A common misconception is that a larger (more dB) antenna is best. Different antennas just disperse the radio waves in a different pattern. If you think about antennas as being a light bulb and some fancy reflectors you would be pretty much on target. An isotropic antenna (exists only in theory) would be like a lightbulb without any fancy reflectors to focus the beam and disperses the radio waves equally in all directions.

The next kind is a dipole (stick) antenna. They basically disperse the radio wave in a big wide doughnut pattern. This would be like putting a reflector on top and bottom of the light bulb. Very little light would be seen directly above or below the light bulb, but a slight increase in light all around the sides of the bulb would result. For a dipole antenna, the higher the dB the flatter the doughnut would be. This would mean that a higher dB antenna is worse if your trying to improve reception in a room directly above your AP, but improve the signal if your further away in the same horizontal plane of the AP.

There are a whole bunch of other antennas + reflectors. A corner reflector would concentrate the radio waves towards one corner. A yagi does something similar except it also has a few large side lobes close by. The can antenna would be akin to a flashlight...etc.

 

[Malk-a-mite]

To the power vs noise question, forgive me, I've been studying for a wireless class all this week.
Normal output looks something like this (in a perfect world I know):

        *
        *
        *
        *
        *
_______***__________

This allows for a number of signals in a given range.

    *    *    *   
    *    *    *   
    *    *    *   
    *    *    *   
____*____*____*____

As you boost your power it looks more like this

    *    *    *   
    *   ***   *   
    *  *****  *   
    * ******* *   
____***********____

And it starts to interfere with the neighboring channels. The higher power the more likely someone nearby will notice the problems and complain. While the frequency that Wireless works on is unregulated it doesn't mean you can do anything you want. In many cases the power output is regulated.

Let's hear it for bad ASCII graphs.