[OT] Power over radio is it a true thing or just a myth ?

[geoffrey mendelson]

On Aug 30, 2009, at 3:00 PM, Orna Agmon Ben-Yehuda wrote:

>
>
> If we stick to the air as our media, then you will need a  
> unidirectional antenna. This is also an idealization, as an antenna  
> which points to one direction, projects energy to the opposite  
> direction as well, and there is also significant power loss to the  
> sides.


Often it can be only omnidrectional in 2 dimensions and only if you  
want to power a circular area. If you want to power all the devices in  
your apartment for example, you can place an omnidirectional antenna  
in the center, or a narrower beam antenna in a corner. The advantages  
of a center one is obvious, you get more power in more all of the  
apartment. A corner antenna placed in the corner where the demand is  
greater, e.g. kitchen, laundry, etc and farthest from where the demand  
is the least, e.g. in a bedroom where you want lights, a clock and  
maybe a TV or radio has a distinct advantage in power levels output  
and the radiation the residents are exposed to.

This has a practical application in the world of computers as you want  
to place a WifI transmitter close to your computers if they are  
clustered and as far away as possible from anyone else's. So I place  
mine where they "leak" out of the building about 5 meters into a  
common entrance yard, but don't reach the street, instead of at the  
other end of the apartment where they would.

Either way, I have no desire to radiate WiFi, or if I could electrical  
power, down into the ground or up into my neighbor's or the street.

Geoff.

-- 
geoffrey mendelson  N3OWJ/4X1GM
Jerusalem Israel geoffreymendelson at gmail.com