Original poster: "Gerry Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
Hi Jim,
Gerry R.
Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>
At 10:12 AM 9/17/2005, you wrote:Original poster: "Antonio Carlos M. de Queiroz" <acmdq@xxxxxxxxxx>
Tesla list wrote:
Original poster: stork <stork@xxxxxxxxxxxxxxxxxxx>
Thank you Jim!
Electrometers are designed to ONLY detect electrostatic fields. They cannot and do not detect magnetic fields. This is the very point of this whole thread. This is a time varying electric field without an associated magnetic field. The transmitter and receiver are longitudinal and non Hertzian. Electrometer probes oriented perpendicular to E field lines capture the radiated E field. The arrangement receives only longitudinal E field radiation. Experiments bear this out, it's not "proven" by some convoluted theory.
This "longitudinal" field is a "local" field in antenna theory. It decreases to practically zero at quite short distance.
In fact, where the "local field" is exactly equal to the "radiated field" is the boundary between "near" and "far fields". Caution, there are other definitions of far field around: e.g. where the plane wave approximation is valid to some level of precision (2d^2/lambda is a common "far field" distance and corresponds roughly to the wavefront being flat enough that a uniformly illuminated circular aperture is diffraction limited)
I personally prefer the term "reactive near field" to indicate that energy is being stored in the field and might be returned to the physical object (n.b. the field around a TC is clearly in this category). In the "radiated far field", no energy is stored, it's just propagating away.