Michael Vasiliev wrote:
The power of the signal is inversely proportional to the square of distance.
That is not precisely accurate.
An undirected point source of EM radiation (or any other type of energy) transmits energy that expands on a sphere from the point of transmittal. The surface area of the sphere expands proportionally to R^2. Therefor, the law of conservation of energy dictates that the energy received over a constant area receiver (say, a 1 cm^2 energy receiver) will decline proportionally to the square of the distance from the transmitter.
As a side note - does that prove that our universe only has three dimensions?
However, if our transmitter is directional, and you keep the transmitter beam focused, so that it does not expand, there is no reason for the energy to almost not discard at all. Of course, the medium through which you transmit the energy may absorb some of it (assuming it is not a vacuum), and it may disperse some more of it, but there is no reason to get 1/R^2, or even 1/R.
Shachar -- Shachar Shemesh Lingnu Open Source Consulting Ltd. http://www.lingnu.com
_______________________________________________ Linux-il mailing list [email protected] http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
