kered said:
That could be, but I know if I lay out my yard stick with coins glued on it, and sweep a quarter from the side at near ground level say 1/2" above the coin, that the edge of the coil will begin detecting the coin before it is any where near direct center of the 10" Tornado and continue until the coil has passed across completely
I also noticed If I raise the coil up to about 5" above the coin and again sweep from the side that coin will not start being detected until I am very near the center. Finer tuning might tighten up the values, but I don't feel the need to over analyze this. This could be proof that the field is curving inward from outer edges of the coil as opposed to a true wedge shape.
I also tried this with my Omega 8000 with its 11 x 7" elliptical DD and with pretty much the same results, it actually detected the quarter sooner, elevated to 5" because of its 7" width.
I suppose I could fix the coil on a jig, pass the quarter under the coil at 5" below the coil, measure the angle and get a rough estimation of the width of the field contacting (for lack of a better description) the quarter at the leading edge of the coil.
This is an air test over clean ground, so what happens to a magnetic field in actual practice may be quite different as the ground can, and trash will cause field permutations.
I do realize that is hardly a scientific test, but still it can be considered a reasonable observation.
Try it for yourself and let's see if my findings correlate with yours.