On Tue, 23 Oct 2007, Jed Rothwell wrote: > I know little about electrical engineering, but > surely we can resolve all questions about this > device fairly easily. If the device can be scaled > up a little, and power can be ramped up to a few > watts that will rule out things like radio tower > transmissions as the source of energy. We would > all be fried if there was that much power in RF transmission.
Yes, but the 'effective aperture' for a resonant coil antenna can be many times larger than the coil diameter, and it depends on Q. High-q tuned circuits can intercept RF from unexpectedly huge regions. 'Effective aperture' or 'antenna aperture' is the diameter of an imaginary absorber-sphere which intercepts the same wattage as the antenna. For enormous Q-factors such as with superconductors, the effective aperture is about a quarter wavelength, and such an antenna absorbs RF energy in an area of 1/8 wavelength squared. In other words, if you have on your lab bench a 500KHz tuned coil antenna made of superconductor, that antenna behaves as a black sphere 150 *meters* in diameter, and will eat up all the 500KHz waves which pass within that distance. This among other things is why Tesla's devices are WEEEEEEEIRD!!! In the early 1990s Nasa engineers patented a VLF antenna which employed an active drive to achive the same effect without superconductors... naming it the "black hole antenna." All this stuff is part of well-accepted antenna theory, and is taught in some fields/waves courses for EEs. But it isn't generally known in other disciplines. Physics students have a hard time understanding why some subatomic particles have a different collision diameter at certain energy levels... and it's explained as "resonance." It's the same topic as Effective Aperture of small resonant antennas, and comes about when the antenna or particle radiates part of the received waves, combining with the incoming waves to create an interference node or "shadow" behind the (tiny) antenna where a net amount of RF energy has gone missing. Even a very tiny antenna can punch a large shadow in the oncoming RF wave pattern. See: http://amasci.com/tesla/dipole1.html http://amasci.com/graphics/dp-absb2.gif Also: Tesla's resonant-antenna power receiver http://amasci.com/tesla/tesceive.html (((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billb at amasci com http://amasci.com EE/programmer/sci-exhibits amateur science, hobby projects, sci fair Seattle, WA 425-222-5066 unusual phenomena, tesla coils, weird sci
