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#1
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John KD5YI wrote:
I think any inductor with the same inductance, Q, and self-resonant frequency will give the same velocity factor and delay as your Bugcatcher. That may or may not be true - I don't have an opinion one way or another - and it is NOT part of my argument. My argument deals only with 75m Texas Bugcatcher coils and other large air- core loading coils used on 75m. My argument is that the velocity factor of a 75m Texas Bugcatcher coil is ~0.02, occupies ~41 electrical degrees on 4 MHz, and exhibits a delay of ~28 nS through the coil. That is my only argument. I am not interested in diversions from that argument. My argument also includes the 100 turn, 10 inch long, 2 inch diameter coil that w8ji used for his 3 nS delay "measurements". If he had used traveling wave current for the measurement, he would have measured approximately 25 nS. Maxwell's equations for slow-wave structures (like a 75m Texas Bugcatcher loading coil) are given in "Fields and Waves ...", by Ramo and Whinnery: pages 467-479 in the 2nd edition. This is one of the references in the Corum IEEE paper. What do you make of Roy's (w7el) statement at: http://www.w8ji.com/agreeing_measurements.htm "As described in my posting on rraa of November 11, the inductor 'replaces' about 33 electrical degrees of the antenna." -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
#2
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![]() "Cecil Moore" wrote in message ... John KD5YI wrote: I think any inductor with the same inductance, Q, and self-resonant frequency will give the same velocity factor and delay as your Bugcatcher. That may or may not be true - I don't have an opinion one way or another - and it is NOT part of my argument. My argument deals only with 75m Texas Bugcatcher coils and other large air- core loading coils used on 75m. If it IS true, then the point I tried to make that you are making a distributed component from a lumped one is valid. That's what caused me to object to your earlier post. And, by the way, I feel the same way you do except about people who are afraid to consider lumped components. Perhaps they do not have what it takes to judge when a proper substitution can be made. John |
#3
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John KD5YI wrote:
"Cecil Moore" wrote in message ... John KD5YI wrote: I think any inductor with the same inductance, Q, and self-resonant frequency will give the same velocity factor and delay as your Bugcatcher. That may or may not be true - I don't have an opinion one way or another - and it is NOT part of my argument. My argument deals only with 75m Texas Bugcatcher coils and other large air- core loading coils used on 75m. If it IS true, then the point I tried to make that you are making a distributed component from a lumped one is valid. That's what caused me to object to your earlier post. And, by the way, I feel the same way you do except about people who are afraid to consider lumped components. Perhaps they do not have what it takes to judge when a proper substitution can be made. John Anyone can take a small inductor, such as Roy described, and try to analyze all the currents and such in it using a distributed model at low or moderate frequencies. If they do, though, they'll just come up with what they'd have come up with treating their small inductor as a lumped element. Cecil has distributed elements on the brain. It's what comes of falling in love with your own theories. 73, Tom Donaly, KA6RUH |
#4
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Tom Donaly wrote:
Anyone can take a small inductor, such as Roy described, and try to analyze all the currents and such in it using a distributed model at low or moderate frequencies. If they do, though, they'll just come up with what they'd have come up with treating their small inductor as a lumped element. One wonders why some people insist on a "small toroidal inductor" which obviously agrees with the lumped-circuit model instead of analyzing a 75m Texas Bugcatcher loading coil which just as obviously violates the presuppositions of the lumped-circuit model. Instead of the "small toroidal inductor", let's discuss w8ji's 100 turn, 2" diameter, 10 inch long air-core coil through which he measured that ridiculous 3 nS delay after which w7el posted some "agreeing measurements" while asserting that the electrical length of the coil was 33 degrees. Does anyone else realize that 33 degrees in 3 nS at 4 MHz is faster than light speed? Are you guys so afraid of losing face that you are willing to post technical falsehoods? -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
#5
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John KD5YI wrote:
If it IS true, then the point I tried to make that you are making a distributed component from a lumped one is valid. That's what caused me to object to your earlier post. There are coils for which the lumped-circuit model is valid. There are coils for which the lumped-circuit model is not valid. I am only interested in discussing coils for which the lumped-circuit model is invalid, i.e. coils that are electrically longer than 15 degrees, e.g. a large air-core 75m Texas Bugcatcher coil which measures about 40 degrees on 4 MHz. I honestly don't know if the lumped-circuit model works for 70 uH toroidal coils. I do know it doesn't work for a 75m Texas Bugcatcher coil. The people who insist on analyzing tiny toroidal coils instead of 75m Texas Bugcatcher coils are afraid of the technical truth and it's easy to see why. -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
#6
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Cecil Moore wrote:
John KD5YI wrote: I think any inductor with the same inductance, Q, and self-resonant frequency will give the same velocity factor and delay as your Bugcatcher. That may or may not be true - I don't have an opinion one way or another - and it is NOT part of my argument. My argument deals only with 75m Texas Bugcatcher coils and other large air- core loading coils used on 75m. My argument is that the velocity factor of a 75m Texas Bugcatcher coil is ~0.02, occupies ~41 electrical degrees on 4 MHz, and exhibits a delay of ~28 nS through the coil. That is my only argument. I am not interested in diversions from that argument. Meaning you don't want anyone to disagree with you. My argument also includes the 100 turn, 10 inch long, 2 inch diameter coil that w8ji used for his 3 nS delay "measurements". If he had used traveling wave current for the measurement, he would have measured approximately 25 nS. No he wouldn't. You don't know what he would have measured. You don't know how to measure it yourself because you don't have any idea of what's going on, theoretically. Maxwell's equations for slow-wave structures (like a 75m Texas Bugcatcher loading coil) are given in "Fields and Waves ...", by Ramo and Whinnery: pages 467-479 in the 2nd edition. This is one of the references in the Corum IEEE paper. Maxwell's equations don't say anything about "slow-wave structures." If they did, you couldn't understand the vector calculus involved, anyway. This is more picking and choosing from authorities. What do you make of Roy's (w7el) statement at: http://www.w8ji.com/agreeing_measurements.htm "As described in my posting on rraa of November 11, the inductor 'replaces' about 33 electrical degrees of the antenna." Are you sure that isn't a quote from Reg Edwards, whose ideas you stole in the first place? Reg thought that antennas were transmission lines. There's nothing wrong with that. Reg even worked out some practical formulas based on his ideas that seemed to work well enough for who they were for. What he didn't do was discover any laws of nature, any more than you have. 73, Tom Donaly, KA6RUH |
#7
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Tom Donaly wrote:
Meaning you don't want anyone to disagree with you. What I invite is someone disagreeing with me about a 75m Texas Bugcatcher coil along with some technical proof that I am wrong. All I have gotten so far is ad hominem attacks. Where's the beef? Dr. Corum's empirically-based equations do not work for toroidal inductors so they are outside the scope of my discussion. Why not discuss the most common large air-core coils used for loading 75m mobile antennas? No he wouldn't. You don't know what he would have measured. I have exactly the same coil that Tom used for his "measurements". I have measured the traveling wave delay through the coil by loading it with a 5k resistor to eliminate reflections. I do know what he would measure if he would only run the experiment correctly. You could do it too if you so chose. x and y are the current sample points. source---x-Tom's coil-y--5k load +-------------------------+ Maxwell's equations don't say anything about "slow-wave structures." If you are saying that Maxwell's equations are invalid for slow-wave structures, your argument is with Ramo, Whinnery, and Dr. Corum, not with me. http://www.w8ji.com/agreeing_measurements.htm "As described in my posting on rraa of November 11, the inductor 'replaces' about 33 electrical degrees of the antenna." Are you sure that isn't a quote from Reg Edwards, whose ideas you stole in the first place? You are free to access the above web page to see who wrote it. If Dr. Corum stole Reg's ideas, he should have given him the credit. Dr. Corum does provide 50 references for his paper but Reg is not one of them. However, here is a partial list: 7. J. D. Kraus, "Antennas" 19. F. E. Terman, "Resonant Lines in Radio Circuits" 23. J. D. Ryder, "Networks, Lines, and Fields" 29. S. Ramo and J. R. Whinnery, "Fields and Waves in Modern Radio" 30. R. W. P. King, "Electromagnetic Engineering" 43. M. Born and E. Wolf, "Principles of Optics" -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
#8
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Cecil Moore wrote:
Tom Donaly wrote: Meaning you don't want anyone to disagree with you. What I invite is someone disagreeing with me about a 75m Texas Bugcatcher coil along with some technical proof that I am wrong. All I have gotten so far is ad hominem attacks. Where's the beef? Dr. Corum's empirically-based equations do not work for toroidal inductors so they are outside the scope of my discussion. Why not discuss the most common large air-core coils used for loading 75m mobile antennas? No he wouldn't. You don't know what he would have measured. I have exactly the same coil that Tom used for his "measurements". I have measured the traveling wave delay through the coil by loading it with a 5k resistor to eliminate reflections. I do know what he would measure if he would only run the experiment correctly. You could do it too if you so chose. x and y are the current sample points. source---x-Tom's coil-y--5k load +-------------------------+ Maxwell's equations don't say anything about "slow-wave structures." If you are saying that Maxwell's equations are invalid for slow-wave structures, your argument is with Ramo, Whinnery, and Dr. Corum, not with me. http://www.w8ji.com/agreeing_measurements.htm "As described in my posting on rraa of November 11, the inductor 'replaces' about 33 electrical degrees of the antenna." Are you sure that isn't a quote from Reg Edwards, whose ideas you stole in the first place? You are free to access the above web page to see who wrote it. If Dr. Corum stole Reg's ideas, he should have given him the credit. Dr. Corum does provide 50 references for his paper but Reg is not one of them. However, here is a partial list: 7. J. D. Kraus, "Antennas" 19. F. E. Terman, "Resonant Lines in Radio Circuits" 23. J. D. Ryder, "Networks, Lines, and Fields" 29. S. Ramo and J. R. Whinnery, "Fields and Waves in Modern Radio" 30. R. W. P. King, "Electromagnetic Engineering" 43. M. Born and E. Wolf, "Principles of Optics" I didn't write that the Corums stole Reg's ideas, I wrote that you did. You know that. Quit trying to hide behind authority. Do you really think that the people who wrote the references you cite, if they were all alive today, would agree with you? Ha, ha, ha. Nice try, Cecil. 73, Tom Donaly, KA6RUH |
#9
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Tom Donaly wrote:
I didn't write that the Corums stole Reg's ideas, I wrote that you did. But I am only quoting Drs. Corum, not Reg. If anyone stole Reg's ideas, it was Dr. Corum, not I. Do you really think that the people who wrote the references you cite, if they were all alive today, would agree with you? As a matter of fact, Dr. Balanis did agree with me when I took his antenna class at ASU in the early 90's. There were some Motorola people in the class who asked, "Why do Intel people know so much about antennas?" Dr. Balanis and I worked closely together on a joint ASU/Intel project. The complete absence of technical rebuttal in your posting is noted. I don't know much about you, Tom, but you seem to be more ad hominem than technical. -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
#10
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Cecil Moore wrote:
Tom Donaly wrote: I didn't write that the Corums stole Reg's ideas, I wrote that you did. But I am only quoting Drs. Corum, not Reg. If anyone stole Reg's ideas, it was Dr. Corum, not I. Do you really think that the people who wrote the references you cite, if they were all alive today, would agree with you? As a matter of fact, Dr. Balanis did agree with me when I took his antenna class at ASU in the early 90's. There were some Motorola people in the class who asked, "Why do Intel people know so much about antennas?" Dr. Balanis and I worked closely together on a joint ASU/Intel project. In the early '90's you hadn't come up with your ideas yet. How could Balanis agree with you before the fact? Again, nice try. The complete absence of technical rebuttal in your posting is noted. I don't know much about you, Tom, but you seem to be more ad hominem than technical. You're being ad hominem by accusing me of being ad hominem. Come up with some evidence that makes sense concerning your ideas and we can talk. 73, Tom Donaly, KA6RUH |
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