|
Tdonaly wrote:
That's a neat picture, Cecil. How did you make the picture of the coil? It is modeled in EZNEC. 'VA' shows a picture. Of course, you can do the same thing with a coil, *or a capacitor* and a couple of identical tank circuits. Then why have you been arguing loud and long against such a possibility? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Richard Clark wrote:
wrote: the far field radiation is irrelevant to the argument over current through a loading coil [a ****-ant argument] The original question was: Is there a current taper through a real-world loading coil. The far-field was not even introduced into the argument until the guru side realized they had lost the argument. Changing the subject of an argument is the oldest logical diversion known to man. Did you eat the lemons, Richard? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil Moore wrote:
So you disagree that 1 amp at 180 degrees is flowing in the opposite direction to 1 amp at zero degrees? If not, why do you disagree that 1 amp at 170 degrees is flowing in the opposite direction of 1 amp at 10 degrees? The direction of current flow is the cosine of the phase angle. wow. I thought just a minor tweek was all that was required. I was wrong. Like I said, Cecil. Never mind. jk |
Art Unwin KB9MZ wrote:
Seems like the model is lacking in all the details and frankly I feel I am looking at an intentianal sham for some reason Sorry you feel that way, Art. That is the output graphic from EZNEC. For instance you do not show coupling to ground which is why I am suspicious since resonance is unavoidably affected by nearby objects as well as ground If there's something wrong, blame EZNEC. I am just reporting what EZNEC sez. You also have not specified a frequency of use ... Of course I have, Art, it's in the .ez file. Since antennas are scalable, the frequency is irrelevant to the diagram. Please download the .ez file. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Wed, 04 Feb 2004 16:13:22 -0600, Cecil Moore
wrote: Richard Clark wrote: the far field radiation is irrelevant to [renders] the argument over current through a loading coil [a ****-ant argument] The original question was: Is there a current taper through a real-world loading coil. a ****-ant question From: Yuri Blanarovich ) Subject: Current in antenna loading coils controversy Date: 2003-10-29 20:03:10 PST "efficiency is greatly affected" ... Date: 2003-10-29 20:07:09 PST "Significant impact on modeling software. If the stuff is not accomodated properly, then results (mainly efficiency) are way off." Date: 2003-10-30 15:36:22 PST "the stronger the field and louder signal." The far-field was not even introduced into the argument All claims have been shown to be hyper-ventilation: a ****-ant argument. |
Jim Kelley wrote:
Cecil Moore wrote: So you disagree that 1 amp at 180 degrees is flowing in the opposite direction to 1 amp at zero degrees? If not, why do you disagree that 1 amp at 170 degrees is flowing in the opposite direction of 1 amp at 10 degrees? The direction of current flow is the cosine of the phase angle. wow. I thought just a minor tweek was all that was required. I was wrong. Like I said, Cecil. Never mind. This keeps happening over and over. Can you at least answer the following questions? In what direction is current at 170 degrees flowing relative to the source (assumed to be at zero degrees)? In what direction is current at 10 degrees flowing with respect to the source. If those are not opposite directions, would you please explain otherwise? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Richard Clark wrote:
a ****-ant question Well, you are entitled to your own opinion. The argument has been going on for months. Some people obviously don't share your opinion. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil Moore wrote:
This keeps happening over and over. Can you at least answer the following questions? In what direction is current at 170 degrees flowing relative to the source (assumed to be at zero degrees)? In what direction is current at 10 degrees flowing with respect to the source. At what instant in time, and, relative to what??!! They're really stupid questions, Cecil. 73, Jim AC6XG |
Jim Kelley wrote:
Cecil Moore wrote: This keeps happening over and over. Can you at least answer the following questions? In what direction is current at 170 degrees flowing relative to the source (assumed to be at zero degrees)? In what direction is current at 10 degrees flowing with respect to the source. At what instant in time, and, relative to what??!! They're really stupid questions, Cecil. Relative to a snapshot of the source at zero degrees, of course. And they are really important questions for comprehending what's happening in reality. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
O.K. I have downloaded the file
Since the dipole is resonant the current magnitudes on either side of the center must be symetrical. If you had a half wave length of wire between the end half waves you would have a half wave ofcurrent with a negative phase which reflects a phase change at half wave intervals. every thing so far appears O.K. Now you aparently changed the wire length so that half is represented by an inductance and the remaining portion stays in linear form to where a phase change occurs again. Now the problem part. In another drawing reflecting a vertical the insertion of an inductance was inserted suddenly created an immmediate phase change even tho its wire make up only consisted of something less than a half wave length on a predetermined basis that any inductance initiates a phase change at both the beginning and the end which I read as false.The phase change is predicated in a way by the wire length that was crunched up to form an inductance.but without capacitive coupling of any sort which is impossible. When looking at Moxons book he shows two dipoles in linear form with a parallel circuit at the center which can represent a loop of a half wave dimension. He also shows the cureent flow in the system from the left to the right until it intersects the parallel loop circuit where it receives current that is flowing counter clockwise within the loop. At the end of the loop the current changes to one that symetry demands i.e current is zero following a sinosoidal shape such that it reaches zero current at the end as symetry requires for a resonant array... Fron Moxons drawing the loop is simulating a mechanical pump operated by the direction of current flow at any particular time where the input and output current are one and the same value so that symetry required for resonance is obtained. Now when I come to your drawing of a vertical I become confused because the top end is clearly zero current flow which presumably is a requirement for resonance but the inductance suddenly becomes dimension less even tho it must have dimensions to reflect phase change thus the current flow assigned to your vertical is clearly flawed. Now Cecil I am not skilled in the art of antennas or modeling as you are but I probably reflect the thinking of the average ham. Thus I would not treat it personaly if you viewed my reasoning as one that reflects a novice. So why not correct the above reasoning in order given so that the average novice can advance in the art because of an enlightning rebuttal.. If we are beyond education such that we cannot be helped without duplication of your own experiences then so be it and we must agree to disagree. As I said earlier nothing personal but I would like the benefit of your enlitenment so I can rebuild on a firmer foundation. Regards Art |
had a girl friend like that once...
" Art Unwin KB9MZ" wrote in message news:PT8Ub.174501$5V2.875722@attbi_s53... Sorry about that, missed the period before co http://web.ukonline.co.uk/g3ldo Art |
Mark Keith wrote:
"----so far I don`t recollect anyone actually measuring a real world coil, and finding max current at the top of the coil." It could be done but it isn`t the ordinary function of loading coils to work with low current in and high current out. One could reason that 1/4-wave back from the open-circuit end of an antenna element a low-impedance high-current point is created. Since the function of a loading coil is usually to supply the missing part of a 1/4-wave in a shortened element, one would expect to find the high-current terminal of the coil facing the transmitter and the low current end of the coil facing the open-circuit end of the element. Best regards, Richard Harrison, KB5WZI |
Art Unwin KB9MZ wrote:
Now when I come to your drawing of a vertical I become confused because the top end is clearly zero current flow which presumably is a requirement for resonance but the inductance suddenly becomes dimension less ... The coil in sqcoil.gif has dimensions, Art, but the drawing is in two dimensions, x & z. The y dimension exists normal to the plane of the drawing. The coil is a square coil in three dimensions. It is 2 feet wide in the x dimension and 2 feet wide in the y dimension. The coils are 0.5 feet apart. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Richard Harrison wrote:
One could reason that 1/4-wave back from the open-circuit end of an antenna element a low-impedance high-current point is created. Since the function of a loading coil is usually to supply the missing part of a 1/4-wave in a shortened element, one would expect to find the high-current terminal of the coil facing the transmitter and the low current end of the coil facing the open-circuit end of the element. I've posted the 'sqcoil.ez' file to my web site that shows low current into the bottom of the coil and high current out of the top of the coil. The radiation pattern shows why that configuration is unpopular - mostly a cloud warmer with a take-off-angle of 48 degrees at 14.7 MHz. However, when 'sqcoil.ez' is run at 29.4 MHz, it turns into a phased array with close to 180 degrees of phase-reversal in the coil and an omni- directional gain of 3+ dBi at a take-off-angle of 12 degrees. -- 73, Cecil http://www.qsl.net/w5dxp/sqcoil.ez -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Thanks for the reply Cecil
It is obvious to me that you are refering to a drawing or GIF as you call it that I cannot retrieve to review thus I cannot continue this discussion as it would resemble a chess game where I could not see opposing positions to ascertain whether a rook was allowed to move as a pawn to thwart any moves I made. I like that analogy Cecil but it does resemble a discussion that cannot progress with clarity or resolve. We are all playing on our home fields where each is not sure how a touchdown was scored, if it was scored and in whose favor.. No wonder this thread has more trails than a fishbone with each poster crunching different parts of the bone on the assumption that all are chewing on the same part. Presumably my posting is now so unclear that it will fit neatly into and conform to the overall thread. Cecil we have severe weather here that it requires a real snow job from me to emerge back into this particular thread !!!!! Regards Art "Cecil Moore" wrote in message ... Art Unwin KB9MZ wrote: Now when I come to your drawing of a vertical I become confused because the top end is clearly zero current flow which presumably is a requirement for resonance but the inductance suddenly becomes dimension less ... The coil in sqcoil.gif has dimensions, Art, but the drawing is in two dimensions, x & z. The y dimension exists normal to the plane of the drawing. The coil is a square coil in three dimensions. It is 2 feet wide in the x dimension and 2 feet wide in the y dimension. The coils are 0.5 feet apart. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
square coils will not work, the current goes so fast, it can't turn the
corners and it all shoots out the end. This causes the current at the top of the coil to be less than that at the bottom. All clearly covered in the Kraus Cliff Notes. "Cecil Moore" wrote in message ... Art Unwin KB9MZ wrote: Now when I come to your drawing of a vertical I become confused because the top end is clearly zero current flow which presumably is a requirement for resonance but the inductance suddenly becomes dimension less ... The coil in sqcoil.gif has dimensions, Art, but the drawing is in two dimensions, x & z. The y dimension exists normal to the plane of the drawing. The coil is a square coil in three dimensions. It is 2 feet wide in the x dimension and 2 feet wide in the y dimension. The coils are 0.5 feet apart. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
W4JLE wrote:
square coils will not work, the current goes so fast, it can't turn the corners and it all shoots out the end. :-) That's why I have developed an octal coil. I'll post the results this weekend. The coil is 4.5 turns, 12 inches in diameter, and 22 inches long. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Wed, 4 Feb 2004 22:37:46 -0500, "W4JLE" w4jle(remove to
wrote: |had a girl friend like that once... You too?? | |" Art Unwin KB9MZ" wrote in message |news:PT8Ub.174501$5V2.875722@attbi_s53... | Sorry about that, missed the period before co | | http://web.ukonline.co.uk/g3ldo | | Art | |
Cecil Moore wrote: I've posted the 'sqcoil.ez' file to my web site that shows low current into the bottom of the coil and high current out of the top of the coil. So according to "convention", standing wave current flows away from the source. Is that your claim? 73, Jim AC6XG |
Jim wrote,
Cecil Moore wrote: I've posted the 'sqcoil.ez' file to my web site that shows low current into the bottom of the coil and high current out of the top of the coil. So according to "convention", standing wave current flows away from the source. Is that your claim? 73, Jim AC6XG If it "flows" anywhere it isn't a standing wave. If there were more of something going out of the coil than going in, the coil would have to be manufacturing that something. Cecil's ideas on waves are well known and lead to some pretty unbelievable results. 73, Tom Donaly, KA6RUH |
Jim Kelley wrote:
Cecil Moore wrote: I've posted the 'sqcoil.ez' file to my web site that shows low current into the bottom of the coil and high current out of the top of the coil. So according to "convention", standing wave current flows away from the source. Is that your claim? No, as explained on my web page. The convention is that forward current flows away from the source and reflected current flows toward the source. Since in the real world, forward current is always greater than reflected current, there is always a net current flow away from the source, by convention. EZNEC displays net current. -- 73. Cecil, W5DXP |
Tdonaly wrote:
If there were more of something going out of the coil than going in, the coil would have to be manufacturing that something. Cecil's ideas on waves are well known and lead to some pretty unbelievable results. Tom, Shirley you understand that current can flow into something for 1/2 cycle and flow out of that something during the next 1/2 cycle. That's what can happen with a phase-reversing coil. For 1/2 cycle, current is flowing into both ends of the coil at the same time. For the other 1/2 cycle current is flowing out of both ends of the coil at the same time. The coil stores energy for the first 1/2 cycle and returns it during the next 1/2 cycle. I'm working on some new EZNEC files. On one file, the current flowing into the bottom of the coil, according to EZNEC, is 0.18 amp at -54 degrees. The current flowing out the top of the coil is 0.2 amp at 126 degrees. Those two currents are flowing in exactly opposite directions. How do you explain that? -- 73, Cecil, W5DXP |
Cecil Moore wrote:
The convention is that forward current flows away from the source and reflected current flows toward the source. Exactly. Since in the real world, forward current is always greater than reflected current, there is always a net current flow away from the source, by convention. The current plot for an antenna is a standing wave plot. The superposition of foward and reflected current is a standing wave. Your "net current" here is a standing wave. Convention dictates that current alternates in direction, and that standing waves don't. They stand. There exists no "reality" in which more current "goes in" one end of a device than "comes out" the other. 73, Jim AC6XG |
On Thu, 05 Feb 2004 14:08:30 -0600, Cecil Moore
wrote: forward current is always greater than reflected current, EZNEC displays net current. On Thu, 05 Feb 2004 14:22:29 -0600, Cecil Moore wrote: the current flowing into the bottom of the coil, according to EZNEC, is 0.18 amp at -54 degrees. The current flowing out the top of the coil is 0.2 amp at 126 degrees. Those two currents are flowing in exactly opposite directions. How do you explain that? Well with the wisdom accumulated thus far you don't know how to use and or interpret EZNEC (fairly obvious). Let's look at the howlers: forward current is always greater than reflected current, compared to: the current flowing into... 0.18 amp The current flowing out ... is 0.2 amp OR the current flowing into... bottom of the coil Forward compared to Reverse The current flowing out ... top of the coil which describes the same direction: into bottom - out of top. Such logical knots (nuts) are derived from the faulty application of EZNEC displays net current. 73's Richard Clark, KB7QHC |
Jim Kelley wrote:
Convention dictates that current alternates in direction, and that standing waves don't. They stand. Heh, heh, the seduction by the math model is worse than I thought. You don't really believe that standing waves don't alternate in direction, do you? Why do you think they call it a loop? The standing wave current changes phase by 180 degrees every half cycle. There exists no "reality" in which more current "goes in" one end of a device than "comes out" the other. But Jim, the original argument was that the current into the coil is the same magnitude and phase as the current out of the coil. Do you think that is a true statement? -- 73, Cecil, W5DXP |
Richard Clark wrote:
Well with the wisdom accumulated thus far you don't know how to use and or interpret EZNEC (fairly obvious). Let's look at the howlers: forward current is always greater than reflected current, compared to: the current flowing into... 0.18 amp The current flowing out ... is 0.2 amp And I'm howling at your ignorance. The current flowing "into" and "out of" is *net* current, not forward or reflected current. The net current is the phasor sum of the forward and reflected currents. They are not the same thing at all. which describes the same direction: into bottom - out of top. If the current into the bottom is at zero degrees and the current out of the top is at 180 degrees, they are flowing in opposite directions which is not "the same direction". -- 73, Cecil, W5DXP |
Cecil Moore wrote: Jim Kelley wrote: Convention dictates that current alternates in direction, and that standing waves don't. They stand. Heh, heh, the seduction by the math model is worse than I thought. It's not so much a matter of being better or worse than you thought. It's just different than what you think. You don't really believe that standing waves don't alternate in direction, do you? I don't think anyone believes that standing waves alternate in direction. Most people know that standing waves are stationary, and that alternating current flows in alternating directions. But the two things are not one in the same. You need to think more carefully about what a standing wave is. Sorry for the dangling prep. The standing wave current changes phase by 180 degrees every half cycle. At a given point is space alternating current changes phase continuously. But standing waves don't change position, and don't have a direction, let alone a *CHANGE* in direction. The current plot on your web page shows a standing wave plot of alterating current magnitude as a function of position. The phase at each position changes continuously with time. Listen carefully. The plot indicates the magnitude (and potentially a phase) of an alternating current as a function of position. The phase at each position changes continuously with time. It's RF AC, but it's not a traveling wave plot. It's not a matter of current flow into or current flow out of; for a standing wave plot it's a matter of the magnitude of current flowing *AT* the specific positions. The current is alternating equally in both directions. There isn't a *net* current flow. 73, Jim AC6XG There exists no "reality" in which more current "goes in" one end of a device than "comes out" the other. But Jim, the original argument was that the current into the coil is the same magnitude and phase as the current out of the coil. But Cecil, the original argument wouldn't have been as big an argument if it had been more accurately stated. Or more precisely, if you hadn't subsequently misstated the facts Yuri had disclosed. It's true that the standing wave current at one end of the coil is greater than it is at the other end. You and I both know why that is so. But there are only so many ways that can be accurately stated before things begin to head off into the ridiculous, the obtuse, and the sublime - directions you have a marked propensity for taking. Reel it back in just a bit. |
Cecil wrote,
Tdonaly wrote: If there were more of something going out of the coil than going in, the coil would have to be manufacturing that something. Cecil's ideas on waves are well known and lead to some pretty unbelievable results. Tom, Shirley you understand that current can flow into something for 1/2 cycle and flow out of that something during the next 1/2 cycle. That's what can happen with a phase-reversing coil. For 1/2 cycle, current is flowing into both ends of the coil at the same time. For the other 1/2 cycle current is flowing out of both ends of the coil at the same time. The coil stores energy for the first 1/2 cycle and returns it during the next 1/2 cycle. I'm working on some new EZNEC files. On one file, the current flowing into the bottom of the coil, according to EZNEC, is 0.18 amp at -54 degrees. The current flowing out the top of the coil is 0.2 amp at 126 degrees. Those two currents are flowing in exactly opposite directions. How do you explain that? -- 73, Cecil, W5DXP So the coil acts precisely as if it were a capacitor. That's what capacitors do, store and release charge. Is that what you're saying? Your coil is getting more versatile all the time. 73. Tom Donaly, KA6RUH |
Cecil wrote,
Heh, heh, the seduction by the math model is worse than I thought. :-) 73, Tom Donaly, KA6RUH |
1. cause currect flow in a coil.
2. remove currect source. 3. Magnetic field collapses inducing voltage in the coil. 4. Doesn't it store energy in the magnetic field? "Tdonaly" wrote in message to Cecil... So the coil acts precisely as if it were a capacitor. That's what capacitors do, store and release charge. Is that what you're saying? Your coil is getting more versatile all the time. 73. Tom Donaly, KA6RUH |
Jim Kelley wrote:
I don't think anyone believes that standing waves alternate in direction. The currents are referenced to the source. When the forward current and reflected current are in phase at zero degrees, they are at a maximum and flowing toward the load so their sum, the net current, is flowing toward the load. 1/2 cycle later, the forward current and reflected current are in phase at 180 degrees so their sum, the net current, is flowing toward the source. You need to think more carefully about what a standing wave is. You need to understand that AC current flows one direction for 1/2 cycle and the opposite direction for the other 1/2 cycle. Current cannot stand still. It must flow. And if it's AC current, it always changes direction during the cycle. Standing current waves are AC and neither DC nor AC current can stand still. If you install a one ohm resistor at a current maximum point, the voltage in phase with the current will be changing phase by 180 degrees every 1/2 cycle. The sign of the cosine of the current phase indicates direction. It's not a matter of current flow into or current flow out of; for a standing wave plot it's a matter of the magnitude of current flowing *AT* the specific positions. Current cannot flow "at" a specific position, Jim. Current has to flow through a specific position in one of two directions. For 1/2 cycle, it flows in one direction and for the other 1/2 cycle it flows in the opposite direction. Like I said, the seduction by your math models is worse than I thought. At everywhere except the current nulls, the standing wave current changes directions every 1/2 cycle. May I suggest you review phasor addition and the meaning of the sign of the cosine phase when dealing with current. -- 73, Cecil, W5DXP |
Tdonaly wrote:
So the coil acts precisely as if it were a capacitor. That's what capacitors do, store and release charge. Is that what you're saying? Your coil is getting more versatile all the time. I am absolutely amazed at the ignorance on this newsgroup. For a resonant tank circuit, while the cap is storing charge, the coil is releasing charge. While the cap is releasing charge, the coil is storing charge. Doesn't anyone understand resonance? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil Moore wrote: Jim Kelley wrote: I don't think anyone believes that standing waves alternate in direction. The currents are referenced to the source. When the forward current and reflected current are in phase at zero degrees, they are at a maximum and flowing toward the load so their sum, the net current, is flowing toward the load. 1/2 cycle later, the forward current and reflected current are in phase at 180 degrees so their sum, the net current, is flowing toward the source. So, now try to align that point of view with the fact that standing waves are stationary - that current flows equally in both directions. Combine it with the fact that there isn't a net flow of current into an antenna. As many electrons flow "out" as flow back "in" to it. You need to think more carefully about what a standing wave is. You need to understand that AC current flows one direction for 1/2 cycle and the opposite direction for the other 1/2 cycle. You need to run a diagnostic on that "logic analyzer" of yours. ;-) It's giving you some bad readings on the available data. Current cannot stand still. Profound. Note that I made no claim to the contrary. Standing current waves are AC and neither DC nor AC current can stand still. Did you understand anything I wrote? You seem to be grappling with some pretty sophomoric notions here, Cecil. It's not a matter of current flow into or current flow out of; for a standing wave plot it's a matter of the magnitude of current flowing *AT* the specific positions. Current cannot flow "at" a specific position, Jim. :-) The plot you made on your web page shows the current flow *AT* every position along two 1/4 wave radiators. Like I said, the seduction by your math models is worse than I thought. Rainman always says he's an excellent driver. You're like him in some ways, Cecil. 73, Jim AC6XG |
Cecil wrote,
The currents are referenced to the source. When the forward current and reflected current are in phase at zero degrees, they are at a maximum and flowing toward the load so their sum, the net current, is flowing toward the load. 1/2 cycle later, the forward current and reflected current are in phase at 180 degrees so their sum, the net current, is flowing toward the source. (snip) Hi Cecil, Actually, net current doesn't flow at all in a standing wave. Current is the rate of change of charge, dQ/dt. In a standing wave, the rate stays put. The charge may be vibrating wildly at a point, but the average rate of change (or even the peak, if that's what's important to you) doesn't move. If it does move, the wave is a traveling wave, not a standing wave. If you were right, then the rate of change of charge would alternately move into and out of your miraculous coil. In other words, there would be an oscillating traveling wave moving first one way and then another, into and out of the coil, and it would do so at both ends, as in some particularly lurid, x-rated movie. This is what happens when you don't understand the math, Cecil. You make stupid mistakes based on a faulty understanding of the fundamentals. I hate to be a fundamentalist like your minister, but I'm sure beginning to appreciate his approach. 73, Tom Donaly, KA6RUH |
W4JLE wrote,
1. cause currect flow in a coil. 2. remove currect source. 3. Magnetic field collapses inducing voltage in the coil. 4. Doesn't it store energy in the magnetic field? "Tdonaly" wrote in message to Cecil... So the coil acts precisely as if it were a capacitor. That's what capacitors do, store and release charge. Is that what you're saying? Your coil is getting more versatile all the time. 73. Tom Donaly, KA6RUH I wrote "charge," not "energy." There's a difference. Cecil writes that current, by which I think he means charge, can flow into both ends of a coil at the same time. He's right, if he indeed is talking about charge and not current, in which case, the charge density will increase in some part of the coil, energy will be stored in an electric field, and the coil will be acting just like a capacitor (with the capacitance to free space understood). 73, Tom Donaly, KA6RUH |
Cecil
I would like to ask you a question regarding inductance coils even tho you know I believe the current is constant An inductor develops a field that travels thru the core and then slays out thru 360 degrees to return to the other end of the coil. Thes lines are directly correllated to the current flow within the inductance and are in equilibrium in terms of mechanical forces. If the current is not constant thru-out the inductance then there are more lines of force at one end than there is at the other, such that the ends would not repel each other,one end will domimate something I have not seen happen. How do you account for the inbalance of the end fields because of so called current gradient that you refer to.If there is no imbalance what happens to dissapate the energy created by the increase of current flow ? I would appreciate your input on the above problem. even tho it appears so simplistic. Regards Artl i "Cecil Moore" wrote in message ... Art Unwin KB9MZ wrote: Did you find something wrong with my suggestion above? Nope, nothing "wrong". I just avoid making assertions when I'm not 95% certain that I am correct. Thus, most of the time, I am unresponsive. I am 95% certain that the average humongous mobile loading coil is not "physically small" and is more like a certain percentage of a helical antenna which indeed does obviously demonstrate a net current gradient. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Thu, 05 Feb 2004 15:50:37 -0600, Cecil Moore
wrote: The net current is the phasor sum of the forward and reflected currents. .... they are flowing in opposite directions Uh-Huh |
Jim Kelley wrote:
So, now try to align that point of view with the fact that standing waves are stationary - that current flows equally in both directions. Are you aware that twice each cycle, the standing wave current is zero at *every* point up and down the transmission line? If so, you must be aware that the standing wave current changes directions twice each cycle on each side of that zero state. You need to run a diagnostic on that "logic analyzer" of yours. ;-) It's giving you some bad readings on the available data. An absolutely meaningless statement unless you are trying to create a diversion away from the facts. Profound. Note that I made no claim to the contrary. Huh, you said that standing current waves stand still. Got news for you, Jim. Standing wave current doesn't stand still. Standing current waves reverse direction every 1/2 cycle. Take a look for yourself with an o'scope. Did you understand anything I wrote? Yes, I understand that you have been seduced by your AC math model based on a DC model. For all AC waves, including standing waves, the current flows in the opposite directions every 1/2 cycle. I am amazed that a physics prof doesn't understand that simple fact of physics. Take a rope, run it through a pulley, and hold one end in each hand. Pull on one end. The other end pulls on your other hand. That's the way AC works. AC current reverses direction every 1/2 cycle. :-) The plot you made on your web page shows the current flow *AT* every position along two 1/4 wave radiators. That's a snapshot, Jim, given by EZNEC, referenced to the source. The current obviously changes direction and phase every 1/2 cycle in real time. Have you never observed standing waves on an o'scope? They look like a kid's jump rope, changing direction every 1/2 cycle. The difference is that 'up' on the jump rope equates to 'toward the load' on a transmission line. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Tdonaly wrote:
Actually, net current doesn't flow at all in a standing wave. Instantaneous standing wave current moves in one direction during 1/2 cycle, and in the opposite direction during the next 1/2 cycle. If you think otherwise, you are simply wrong. Have you never observed standing waves on an o'scope? It looks like a kid's jump rope. And Tom, one of the strictest laws of physics is that current cannot stand still. Saying that "current doesn't flow at all" is ridiculous. When the current is flowing into both ends of the coil at the same time, charge is being stored in the coil. 1/2 cycle later, the charge flows out of the coil at both ends. In one of my examples, the current at the bottom of the coil is 0.18 at - 54 degrees. The current at the top of the coil is 0.2 at 126 degrees. Last time I checked, 54+126 = 180 degrees indicating that the current at the bottom of the coil is 180 degrees out of phase with the current at the top of the coil. That means the two currents are flowing in opposite directions at the two ends of the coil. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Tdonaly wrote:
I wrote "charge," not "energy." There's a difference. Cecil writes that current, by which I think he means charge, can flow into both ends of a coil at the same time. He's right, if he indeed is talking about charge and not current, in which case, the charge density will increase in some part of the coil, energy will be stored in an electric field, and the coil will be acting just like a capacitor (with the capacitance to free space understood). Nice crawfishing job, Tom. The direction of charge flow is the same as the direction of current flow, assuming electron current flow (as opposed to hole current flow). If charge is flowing into each end of the coil at the same time, then instantaneous current is, by definition, flowing into each end of the coil at the same time for 1/2 of the RF cycle. Good to see you coming to your senses like I knew you would. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
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