Lyle:
Recent stories about 2.5 Gbps over standard power lines, and available at any wall socket in the home (thought possibly also dubious), are reportedly due to be tested in the next few months. Something like that certainly would throw a monkey wrench in ALL broadband technologies, including DWM!
They claim they don't actually use the power lines themselves, but, instead, use the "magnetic field which surrounds all wires carrying a current", and are thus not restricted by the bandwidth of the power systems (????).
Been a while since I was in school, but, a quick review of some of my old dusty textbooks and my old dusty memory tells me that ALL electric current flows in said field; we are used to thinking of it flowing "through" the wire becuase, at lower frequencies, the field is so close to the wires that it is OK to assume it is "in" the wires. However, when I worked for Hewlett Packard on GHz range spectrum analyzers, it was VERY easy to see that HIGH frequency signals, such as those required for high bit rate digital transmission, paid little regard to what we call "wires"; they more or less went wherever they wished, and the greatest challenge in working at such high frequencies was trying to persuade the signal to follow some sort of reasonable path from "gazinta" to "gazouta" without spraying all over everything else in the system! About half of our work was science; the rest was probably some sort of benign "voodoo" we stumbled across through experience.
All this stuff is fun to read about but I remain convinced the physical laws I've seen over the years are still being enforced by SOMETHING. Otherwise, when I tripped over a blanket in my living room yesterday, why did I fall on my keester, instead of floating to the ceiling. I REALLY, REALLY wanted to float up, with all my heart, but alas, I went down HARD!
Larry |
