On Tue, 23 Oct 2007, William Beaty wrote: > 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.
Oops, that should be 1/16 wavelength squared. For 18MHz, that's an absorber region of around sixteen square meters. An ideal resonant antenna absorbs half the RF energy passing through that region, and radiates (scatters) the other half. The antenna can be an extremely tiny coil, yet the process still works the same. So, if some shortwave antenna is sending a few milliwatts per square cm through Ron's lab, and his coil happens to hit its resonant frequency, then his results are conventional and have nothing to do with physics anomalies. Moving Ron's device to other locations should show the truth. I see that WP has an entry: http://en.wikipedia.org/wiki/Aperture_(antenna) They say wavelength squared divided by 4*pi, rather than by 16 Another way to think about it: a standard half-wave dipole antenna works the same whether made from #8 wire or #28 wire, yet the broadside area of the wire has two very different values. Why? Don't these two antennas absorb very different amounts of RF, and cast very different RF shadows? Nope. It's because a wire antenna creates it's own EM field, and the absorption process involves the waves radiated by the antenna cancelling out the incoming EM and punching a large "rf shadow" in the waves passing by the antenna. There's an interference pattern with a big black node downstream from the antenna. Where RF is concerned, the "shadow" of an antenna doesn't look like a piece of thin wire, instead it's a fuzzy circle about a quarter wavelength across. BTW this also explains why sodium vapor looks black under sodium light, where sodium atoms an angstrom in diameter and couldn't possibly act as significant absorbers. But high-Q resonating atoms can be "virtuall large" absorbers of waves which are 5900 angstroms wavelength. Tiny high-Q resonant antennas emit very strong waves of their own, so they act the same as wire antennas thousands of times larger. (((((((((((((((((( ( ( ( ( (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
