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#51
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RSGB RadCom December 2007 Issue
"Stefan Wolfe" wrote in message ... "Mike Kaliski" wrote in message ... Integral calculus has been described as one of the greatest advances in mathematical science, but that is still only an approximation method and nobody complains about that. Mike, it is hard for me to let this go (but it is off topic). Integral calculus is not an approximation, it is exact. The prior art, the summation method of adding the areas of small rectangles, was the approximation. The genius of integral calculus was that it was able to sum an infinite number of infinitely small rectangles and come up with an exact answer. For the answer to be exact, it was necessary to deal with infinity (undefined) and the concept actually works. It even works in many cases where there is an asymptote that is infinitely long (f(x) = 1/x**2)). END OF COMMENT (no, I will not offer experimental proof that integral calculus is exact :-)) Stefan All true and it works very well. It's just that being forced into accepting such concepts as infinity and the square root of minus one without being able to pin down exactly what they are shows up how limited we are in our abilities to deal with the true nature of the universe. How can anyone really get to grips with such concepts as an infinity of infinities? Mike G0ULI |
#52
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RSGB RadCom December 2007 Issue
art wrote:
By the same token I am challenging to prove the veracity of the additional statement that a sino soidal current is present at every segment point. If one threads a toroidal transformer over a dipole wire, one will observe a sinusoidal waveform (if the source is sinusoidal). -- 73, Cecil http://www.w5dxp.com |
#53
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RSGB RadCom December 2007 Issue
Stefan Wolfe wrote:
"Tom Donaly" wrote: Have you verified this experimentally, Cecil? If you did, how did you do it? This work has already been done. Thanks Stefan, Tom apparently believes I should reinvent the wheel every time I ride my Harley. :-) -- 73, Cecil http://www.w5dxp.com |
#54
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RSGB RadCom December 2007 Issue
Richard Clark wrote:
The old saw of dipoles not needing a ground (one of those things that makes them so much "better" than verticals) is confounded because they do need a ground - if you want more gain. What's the difference in free space gain between a vertical dipole and a horizontal dipole? :-) -- 73, Cecil http://www.w5dxp.com |
#55
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RSGB RadCom December 2007 Issue
On Nov 15, 2:41 pm, Cecil Moore wrote:
Reflections occur only at physical impedance discontinuities. Richard Feynman said there is a probability that reflection will occur at any point within a partially reflecting media. He explained that all the probabilities (including phase) sum in order to generate the net, observed effect. Your observation about the full-wave loop is probably a good example. 73, ac6xg |
#56
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RSGB RadCom December 2007 Issue
John Smith wrote:
"From the above, are the two in a constant state of interaction?" On page 1 of Terman`s "Electronic and Radio Engineering": "These waves, which are commonly called radio waves, travel with the velocity of light and consist of magnetic and electric fields that are at right angles to each other and are at right angles to the direction of travel. If these electric and magnetic fields could actually be seen, the wave would have the appearance indicated in Fig. 1-1." Maxwell`s first field equation says that a changing magnetic field will produce an electric field. The second equation says that a changing electric field will produce a magnetic field. The alternating magnetic field creates an alternating electric field in the space surrounding it. Due to the alternation of the electric field an alternating displacement current will exist in space, which will give rise to another alternating magnetic field in the space surrounding the displacement current, etc., etc., etc.. Maxwell`s proof is courtesy B. Whitfield Griffirh, Jr.`s "Radio-Electronic Transmission Fundamentals", now in reprint by Scitech Publidhing, Inc.. Best regards, Richard Harrison, KB5WZI |
#57
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RSGB RadCom December 2007 Issue
Richard Harrison wrote:
... The alternating magnetic field creates an alternating electric field in the space surrounding it. Due to the alternation of the electric field an alternating displacement current will exist in space, which will give rise to another alternating magnetic field in the space surrounding the displacement current, etc., etc., etc.. Maxwell`s proof is courtesy B. Whitfield Griffirh, Jr.`s "Radio-Electronic Transmission Fundamentals", now in reprint by Scitech Publidhing, Inc.. Best regards, Richard Harrison, KB5WZI Richard; Thanks for taking the time to post that data. Of course, in my "addled way of thinking", I still see the probability of a media in which these actions are taking place (electric to magnetic and magnetic to electric )--such as when you swing a wire (media) through a magnetic field. But, really, it is all still a question ... anyway, pondering keeps me outta the bars. :-) Regards, JS |
#58
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RSGB RadCom December 2007 Issue
Jim Kelley wrote:
Richard Feynman said there is a probability that reflection will occur at any point within a partially reflecting media. Of course, there are always 2nd, 3rd, ... Nth order effects. On this newsgroup, we are usually talking about first order effects. I had a recent email exchange with someone talking about the part of the ground wave that escapes absorption because of the earth's curvature and is probably ignored by NEC simulators but not by AM broadcasters. -- 73, Cecil http://www.w5dxp.com |
#59
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RSGB RadCom December 2007 Issue
Richard Harrison wrote:
Maxwell`s first field equation says that a changing magnetic field will produce an electric field. The second equation says that a changing electric field will produce a magnetic field. Does this cause and effect chain of events result in a phase lag between the electric and magnetic fields? -- 73, Cecil http://www.w5dxp.com |
#60
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RSGB RadCom December 2007 Issue
On 16 Nov, 10:38, Cecil Moore wrote:
Richard Harrison wrote: Maxwell`s first field equation says that a changing magnetic field will produce an electric field. The second equation says that a changing electric field will produce a magnetic field. Does this cause and effect chain of events result in a phase lag between the electric and magnetic fields? -- 73, Cecil http://www.w5dxp.com I would like more than that! I would like to know what Terman had to say about radiation which is a cause of most discussion the summation of which is not accepted by the IEEE. I don't think he has given any credit to Maxwell, Faraday, Heaviside or any of the pioneers in any of his books so it would be interesting to know why his wrestling with the mechanics of radiation was to no availe!. And Richard, when you have finished reading from Terman to get us to sleep, would you consider for your next book to read to us, like Lady Chatterlies Lover by D.H. Lawrence? That book may well prevent you going to sleep as well while reading on the net Most of us have read all the volumes by Terman so a different reading book may well be of more interest. Art |
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