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On Nov 15, 10:50*pm, Jeff Liebermann wrote:
On Sun, 15 Nov 2009 17:00:10 -0800 (PST), Art Unwin wrote: Very true, but the measured *length is never repeatable. Only at the point of a period is where it is repeatable which is how a cycle comes into being. One cycle = one period = one wavelength Do you have a problem with this? Ofshoot can be essentially removed or minimised by just the addition of a resister but such methods are not included in antenna computer programs. Adding a resistor will increase the resonant length of an antenna by 5% to 8%. *Amazing. *I didn't know that. *Since resonance is where the inductive and cazapative reactances cancel, leaving only the real part of the antenna impedance, I would think that adding a resistor anywhere would have no effect on the reactive components. Again what ever trips your trigger, horse shoes or Maxwells equations. When I was younger, it was sex, drugs, and rock and roll. *These days it's pills, politics, and entertainment value that keeps me going. Only when accurate metrics are inserted in a program can the accuracy of Maxwell's equations be shown and the half wave length can never be stated accurately. How accurately would you like them to be stated? * 1%? *0.1%? 0.00000001% Accuracy is usually expressed with numbers. *I fail to see any numbers. *There's also a question of what's "good enough". *Infinite resolution and accuracy doesn't do me much good if the operating bandwidth of the antenna is substantial, or the operating requirements of system are rather minimal. My antennas are exact and repeatable. *Not only that, I can also repeat my mistakes every time. Yes you have shown evidence of that. To err is human. *Reassurances are not required. For my mistakes, I'll accept responsibility but not blame. Two wrongs don't make a right, but do eliminate two possibilities, thus eventually leading to the right answer. Positive feedback is inherently unstable. *One does not learn by getting positive acclamation and praise. *One learns from negative feedback which is inherently stable and a much more effective learning experience. Maybe true but physics demands accuracy Physics does not demand accuracy. *However, my customers might. which explains the heavy useage of constant added to justify the use of an equal sign. None of my work is linear. *Therefore constants added as fudge, finagle, or tweak factors are useless. *I prefer to multiple my results in order to conjure the correct answer. Same thing goes for the myriad of particles invented that are not seen or measurable. Yep. *I suck them up in my vacuum cleaner when they start to become measurable. This because those who delve in physics sometimes replace a constant with a new invented particle that can substantiate equilibrium or its cousin "equal" I'll look in the vacuum cleaner bag next time I have a chance for any new particles. You know, *a well known former ham Stephen Best got hold of a new antenna program that had strict adherence to Maxwells laws. The program relied on Poynting circle as being representitive * for all forces in radiation. The program ,probably more than I can afford. produced a radiator that was not straight according to the old wives tale that is propagated by hams. It showed something like a tennis ball where multiple wavelengths of radiator were stuffed inside and where balance or equilibrium was obtained. In his study which was around a half wave radiater produced a radiation pattern that was a perfect hemisphere that all on this group stated was impossible to attain. ( actually it was based on a full wave where the ground plane supplied the mirror image) Possibly in our time, that will make it into the newer physics books, that will force the re thinking of radiation. This paper is on the WWW but I leave it to you to show that it must be in error as it is not yet in the books! I think you mean this: http://www.cst.com/Content/Applications/Article/A+Small,+Efficient,+L... I've been trying to understand it for some time. Again, it's not my place to find your errors. *It's your place to prove and demonstrate your allegations. At the same time opponents will bring forwards Toms adage W8TI, that for maximum efficiency a radiator must be straight, thus leaving him with the onus of showing that Steven Best efforts were all wrong by the use of the soon to be corrected theory corrections before old theories are fully discounted where all may read it for themselves in *a book. Dr Best didn't seem to mention anything about the design being any more efficient than a larger antenna. *He had a design requirement to fit an antenna inside a 0.04 wavelength diameter ball, and optimized his design around that requirement. *Getting 1.6dBi of gain out such a small antenna is impressive. Incidentally, his design is NOT a half-hemisphere. *He uses the symmetry of the antenna to dramatically reduce his calculation time. Yes, there are some things that NEC doesn't so very well, or rather other programs do much better. *For example, for microstrip and slot antennas, I'm trying to learn Mstrip40: http://www.spl.ch/software/MultiSTRIP/Manual.htm when not posting inane drive to Usenet. -- Jeff Liebermann * * 150 Felker St #D * *http://www.LearnByDestroying.com Santa Cruz CA 95060http://802.11junk.com Skype: JeffLiebermann * * AE6KS * *831-336-2558 Jeff, Art is going to be your buddy forever. He doesn't care whether you praise him, bash him or anything in between, but he loves long replies. Jimmie |
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