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Art Unwin wrote:
On Feb 24, 7:50 pm, tom wrote: tom wrote: Thanks Roy. I was rushed at the time and also didn't care too much, since it was obvious that even though the elements weren't parallel or on quite the same centerline, they were very close to it. He picks at nits when he says his antennas are different. I could get similar results from a good windstorm. tom K0TAR Ok, revisiting things now that I have time, I discovered something, which The Art may (ok, will) get off into an incomprehensible rant about. I did a simple normalization. I calculated the lengths of the elements and the location of their centerpoints. I then calculated the distance between the centerpoints. I then put it all in a nice level and square 2 element array. I left the diameters alone. New endpoints - -37.455 -219.135 707 -37.455 219.135 707 1 37.455 -195.45 707 37.455 195.45 707 1.25 Results at 14.175 using EZNEC+ 5 Gain F/B Original 9.87 dBi 7.84 Normalized 10.29 dBi 8.58 The impedance curves were not different enough to be of note and were matchable to 50 ohms with good efficiency. I'll take the one with better gain and F/B that's also nice looking with elements that are easier to mount because they're at 90 degree angles, thank you. Yes, run-on sentence. tom K0TAR Tom I have no problem with your choice of going with the one with the best front to back, what ever one that is. The crux of the matter is under the equations of Maxwell optimiser programs do not provide the planar form as the best radiator. I understand that Roy now has an optimiser program for sale and I fully expect for it to follow the same pattern as well as prove my point on the circular wound antenna as apparently he supplies more than enough segments assuming the computer has the power to use them. However a look at the larger picture the same particulars provided state that one can manipulate the elements to occupy a small volume as long as the resonance and equilibrium restrictions are held to. I see that as the real prize that will come from my workif one had the equipment to do the optimization. Ofcourse if Roy's program still provide the yagi as the optimizer result then there is a definate conflict with other computer programs that use Maxwells equations. Looking back at the idea that waves are the carrier of communication it leaves us with the silly propersition that a Faraday cage perforations must be less in size to that of the incoming wave! Thus for a cage for use on the top band can live with openings that are a bit smaller than 180 metres! Now some text books have dropped the size opening to approx 1/10 of a WL which is still way to large to enclose the eddy current rotation.Einstein failed to prove his theorem and was forced to invent quantum mechanics which provided the answer of particles that he anticipated and now with the above standard physics figures supplies the same result. So it is up to the ham himself to decide whether it is worthwhile to have an antenna sensitive to all signals that are thrown at it, where it operates in a smaller volume than the yagi or stay with one more pleasing on the eye. I personally do not have the equipment to pursue what appears to be smaller antennas than presently used all the way down to point radiation. What hams have to recognise now is that the much vaunted antenna programs do not consider the yagi as an optimized array and to decide whether to ditch the programs or pursue what the programs based on Maxwell provide to its limits. Art Unwin KB9MZ......xg Yup, I was correct, pretty much incomprehensible nonsense. And the comprehensible parts were worthless, as usual. Go back on your meds kid. And stay there. tom K0TAR |
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