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#1
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Richard,
It's not clear what aspect of your sources is "Rnd", but the fact that they are monochromatic is still problematic. 73, ac6xg Jim Kelley wrote: Very nice work. Dissapointingly ambiguous results. Thank you. ac6xg Richard Clark wrote: On Thu, 03 Nov 2005 15:13:53 -0800, Jim Kelley wrote: use an array of non-coherent sources EZNEC+ ver. 4.0 Dipole in Ring of Rnd Sources 11/3/2005 5:39:03 PM --------------- LOAD DATA --------------- Frequency = 70 MHz Load 1 Voltage = 0.002611 V. at -33.23 deg. Current = 3.627E-05 A. at -33.23 deg. Impedance = 72 + J 0 ohms Power = 9.47E-08 watts Total applied power = 1364 watts Total load power = 9.47E-08 watts Total load loss = 0.0 dB then moved quarterwave: EZNEC+ ver. 4.0 Dipole in Ring of Rnd Sources 11/3/2005 5:41:17 PM --------------- LOAD DATA --------------- Frequency = 70 MHz Load 1 Voltage = 0.00676 V. at -110.1 deg. Current = 9.389E-05 A. at -110.1 deg. Impedance = 72 + J 0 ohms Power = 6.348E-07 watts Total applied power = 1364 watts Total load power = 6.348E-07 watts Total load loss = 0.0 dB then moved backwards a quarterwave EZNEC+ ver. 4.0 Dipole in Ring of Rnd Sources 11/3/2005 5:44:52 PM --------------- LOAD DATA --------------- Frequency = 70 MHz Load 1 Voltage = 0.004604 V. at 29.97 deg. Current = 6.395E-05 A. at 29.97 deg. Impedance = 72 + J 0 ohms Power = 2.944E-07 watts Total applied power = 1364 watts Total load power = 2.944E-07 watts Total load loss = 0.0 dB EZNEC+ ver. 4.0 Yagi in Ring of Rnd Sources 11/3/2005 5:48:14 PM --------------- LOAD DATA --------------- Frequency = 70 MHz Load 1 Voltage = 0.07004 V. at 66.62 deg. Current = 0.005837 A. at 66.62 deg. Impedance = 12 + J 0 ohms Power = 0.0004088 watts Total applied power = 1364 watts Total load power = 0.0004088 watts Total load loss = 0.0 dB moved back halfwave: EZNEC+ ver. 4.0 Yagi in Ring of Rnd Sources 11/3/2005 5:51:43 PM --------------- LOAD DATA --------------- Frequency = 70 MHz Load 1 Voltage = 0.09133 V. at -53.63 deg. Current = 0.007611 A. at -53.63 deg. Impedance = 12 + J 0 ohms Power = 0.0006952 watts Total applied power = 1364 watts Total load power = 0.0006952 watts Total load loss = 0.0 dB (and really see what's going on) Hmmm, at least 1000 times more response... so what's going on? (aside from a possibly poor implementation of random). Trying to refine the sources table with tighter random assignments is positively brutal under EZNEC's primitive (read no) handling of columnar data. 73's Richard Clark, KB7QHC |
#2
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On Fri, 04 Nov 2005 10:32:07 -0800, Jim Kelley
wrote: It's not clear what aspect of your sources is "Rnd", but the fact that they are monochromatic is still problematic. Hi Jim, You lost me on that curve. Monochromatic. The sources exhibit an even distribution of varying phase in a random order. That was tedious to accomplish, but achievable - in a group of 360 possible degrees of phase, you eventually cover the field. On the other hand, if you are suggesting that there needs to be an equally random distribution of frequencies then that has its obvious issues of practicability. What is the lowest frequency and what is the highest frequency? That question has all the hallmarks of which infinity is the biggest? Anyway, I would surmise that if I could achieve both random phase and frequency distribution, then the difference between a simple dipole's response and that of a yagi antenna would be trivial. This would be a given seeing that the parasitic elements would be virtually invisible, rendering the "driven" element un-differentiable from the simple dipole. 73's Richard Clark, KB7QHC |
#3
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![]() Richard Clark wrote: Anyway, I would surmise that if I could achieve both random phase and frequency distribution, then the difference between a simple dipole's response and that of a yagi antenna would be trivial. Trivial would be a nice change. This would be a given seeing that the parasitic elements would be virtually invisible, rendering the "driven" element un-differentiable from the simple dipole. i.e. what Roy said. But I think there's still more to it. I tried to give the other Richard a hint about it but it didn't resonate. 73, ac6xg |
#4
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Jim Kelley wrote:
i.e. what Roy said. But I think there's still more to it. I tried to give the other Richard a hint about it but it didn't resonate. Then obviously your XC didn't equal your XL. -- 73, Cecil http://www.qsl.net/w5dxp |
#5
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![]() Cecil Moore wrote: Jim Kelley wrote: i.e. what Roy said. But I think there's still more to it. I tried to give the other Richard a hint about it but it didn't resonate. Then obviously your XC didn't equal your XL. Probably just a difference in wavelength. ac6xg |
#6
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On Fri, 04 Nov 2005 11:42:43 -0800, Jim Kelley
wrote: This would be a given seeing that the parasitic elements would be virtually invisible, rendering the "driven" element un-differentiable from the simple dipole. i.e. what Roy said. On Wed, 02 Nov 2005 00:11:09 -0800, Roy Lewallen among many things wrote: I have to admit, I was looking at this a[s] more of a problem of equal signals arriving from all directions Hi Jim, I also approached the problem the same way, this is in glaring contrast to what I've written in the past two posts which are vastly divergent from this sense of "equal signals." As I originally presented data from the model of "equal signals arriving from all directions" it presented that a dipole's response was separable from that of a yagi, and showed more response which contradicts some correspondents, and aligns with others. Such an outcome stands to reason, the yagi cannot see all sources, the dipole can. If I illuminated the yagi from each source in turn (all others off) and correlated the response to the source's angle, the composite would simply reveal the characteristic yagi response lobe and the sum of those powers MUST fall below the total power available to the dipole. The one over-riding difference between all these scenarios and the expectations of the yagi is that the yagi is not illuminated with a plane field, but with a radial field. The composite front of many sources presents a complex antenna (the yagi) with the appearance of a wave of extremely high curvature impinging upon it. The mechanics of gain/directivity are not going to function in the same manner to that yagi for both fashions of applying the power. Hence the yagi fails to exhibit a higher response than the simple dipole. 73's Richard Clark, KB7QHC |
#7
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![]() Richard Clark wrote: On Fri, 04 Nov 2005 11:42:43 -0800, Jim Kelley wrote: This would be a given seeing that the parasitic elements would be virtually invisible, rendering the "driven" element un-differentiable from the simple dipole. i.e. what Roy said. On Wed, 02 Nov 2005 00:11:09 -0800, Roy Lewallen among many things wrote: I have to admit, I was looking at this a[s] more of a problem of equal signals arriving from all directions Hi Jim, I also approached the problem the same way, this is in glaring contrast to what I've written in the past two posts which are vastly divergent from this sense of "equal signals." As I originally presented data from the model of "equal signals arriving from all directions" it presented that a dipole's response was separable from that of a yagi, and showed more response which contradicts some correspondents, and aligns with others. Such an outcome stands to reason, the yagi cannot see all sources, the dipole can. If I illuminated the yagi from each source in turn (all others off) and correlated the response to the source's angle, the composite would simply reveal the characteristic yagi response lobe and the sum of those powers MUST fall below the total power available to the dipole. The one over-riding difference between all these scenarios and the expectations of the yagi is that the yagi is not illuminated with a plane field, but with a radial field. The composite front of many sources presents a complex antenna (the yagi) with the appearance of a wave of extremely high curvature impinging upon it. The mechanics of gain/directivity are not going to function in the same manner to that yagi for both fashions of applying the power. Hence the yagi fails to exhibit a higher response than the simple dipole. 73's Richard Clark, KB7QHC Let me thank you again for the work you've put in on this. The thing is, the idea of squeezing a dipole field pattern into the shape of a Yagi pattern for example, pretty much dictates that with the proper field geometry, we should be able to realize equal amounts of energy in both antennas. I think that's the correct answer. I'm just trying to see a way to get to it. Another approach might be to integrate the results from a large number of point sources. 73, AC6XG |
#8
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On Fri, 04 Nov 2005 15:39:18 -0800, Jim Kelley
wrote: Another approach might be to integrate the results from a large number of point sources. Hi Jim, I just did that - literally. 73's Richard Clark, KB7QHC |
#9
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Richard Clark wrote:
. . . Such an outcome stands to reason, the yagi cannot see all sources, the dipole can. If I illuminated the yagi from each source in turn (all others off) and correlated the response to the source's angle, the composite would simply reveal the characteristic yagi response lobe and the sum of those powers MUST fall below the total power available to the dipole. Yet if you provide the same power to the dipole and the Yagi and integrate the total field from each, the total field powers from both are the same. So is reciprocity invalid? Roy Lewallen, W7EL |
#10
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On Fri, 04 Nov 2005 15:45:39 -0800, Roy Lewallen
wrote: Richard Clark wrote: . . . Such an outcome stands to reason, the yagi cannot see all sources, the dipole can. If I illuminated the yagi from each source in turn (all others off) and correlated the response to the source's angle, the composite would simply reveal the characteristic yagi response lobe and the sum of those powers MUST fall below the total power available to the dipole. Yet if you provide the same power to the dipole and the Yagi and integrate the total field from each, the total field powers from both are the same. So is reciprocity invalid? Hi Roy, No, the presumption: that this specific problem supports that reciprocity is invalid. Feel free to exhibit that the sum of powers, from identical remote sources, located in a locus of points equidistant from a given point, applied to 1. a dipole; 2. a yagi demonstrate identically recovered power. This is not the same as applying the same power to both and integrating at a locus of points equidistant from a given point. I could, of course, be wrong. I will investigate further if you have any constructive suggestions such as Jim offered. I think it would be instructive to be able to confirm it through available tools. 73's Richard Clark, KB7QHC |
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