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#121
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Cecil Moore wrote:
... What happens when me measure the light frequency of distant galaxies while, during the travel of that light, light-years were getting longer and seconds were getting shorter? Hint: same thing that happens when the time base knob on an oscilloscope gets loose and slips. (That actually happened to me and the result was an epiphany about space/time.) OK. Reading you clear now. Just one of those "DUH!" moments I have. Thanks for your time; I am embarrassed ... Regards, JS |
#122
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Art Unwin wrote:
"I am still of the belief that on a fractional wave antenna the current travels on both the outside and the inside of the radiator." That`s so at DC but not at HF. HF only travels on the outside layer of a conductor as more current-opposing flux lines encircle the conductor`s center than encircle the conductor`s surface or outer layer. See Fig. 2-10 on page 22 of Terman`s 1955 opus. Art also is confused about current distribution on resonant antennas of various lengths. Terman can help there too. On page 866 Terman wrote: "The current distribution as observed in such a resonant wire (1/2-wave open at both ends) serving as an antenna ordinarily approximates very closely the distribution that would be obtained on the assumption of zero loss. provided the wire length does not exceed 8 to 10 wavelengths. The current distribution, accordingly has the character illustrated in Fig. 23-3." Also on page 866: "----to a first approximation the current distribution can be taken as that for a line with zero losses; it then has the characteristics discussed in Sec.4-5." Page 91, Fig. 4-3 shows the vectors (phasors) E1 & E2 at an open-circuited load as happens at the antenna tips, Conduction current ends at the conductor tip. Current interruption collapses the magnetic field and induces an opposite current causing a zero sum current at the tip, but the induced voltage is of the same polarity as the incident votage making a voltage double at the antenna tip. Energy is conserved. Best regards, Richard Harrison, KB5WZI |
#123
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On Nov 14, 3:11*pm, (Richard Harrison)
wrote: Art Unwin wrote: "I am still of the belief that on a fractional wave antenna the current travels on both the outside and the inside of the radiator." That`s so at DC but not at HF. HF only travels on the outside layer of a conductor as more current-opposing flux lines encircle the conductor`s center than encircle the conductor`s surface or outer layer. See Fig. 2-10 on page 22 of Terman`s 1955 opus. Art also is confused about current distribution on resonant antennas of various lengths. Terman can help there too. On page 866 Terman wrote: "The current distribution as observed in such a resonant wire (1/2-wave open at both ends) serving as an antenna ordinarily approximates very closely the distribution that would be obtained on the assumption of zero loss. provided the wire length does not exceed 8 to 10 wavelengths. The current distribution, accordingly has the character illustrated in Fig. *23-3." Also on page 866: "----to a first approximation the current distribution can be taken as that for a line with zero losses; it then has the characteristics discussed in Sec.4-5." Page 91, Fig. 4-3 shows the vectors (phasors) E1 & E2 at an open-circuited load as happens at the antenna tips, Conduction current ends at the conductor tip. Current interruption collapses the magnetic field and induces an opposite current causing a zero sum current at the tip, but the induced voltage is of the same polarity as the incident votage making a voltage double at the antenna tip. Energy is conserved. Best regards, Richard Harrison, KB5WZI * * Could you give a similar description only this time make it a 5/8 wavelength antenna? |
#124
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Google
Secrets of the aether Three papers written by two physics peoiple in Southern Illinois Now also in book form released about two years ago Art Reference found at: http://16pi2.com/ I guess you mean "Two phyicists". Problem is they are not physicis: No degrees listed, no university affiliation, no publishing list, no professional society affiliation, papers not published in scholarly journals therefore no peer review. Probably more that I have missed. Even where the three papers were presented (PIRT 2006) looks like it would not stand up to too much scrutiny. At that point I lost interest. 73, Frank |
#125
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Richard Harrison wrote:
... Best regards, Richard Harrison, KB5WZI Sorry I "clipped" your text so severely, my text will be brief ... It surprises me anyone would think RF would not choose the outside of ANY RADIATING element--this is where is MUST make the "jump" to the ether ... isn't logic enough? Regards, JS |
#126
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Frank wrote:
... I guess you mean "Two phyicists". Problem is they are not physicis: No degrees listed, no university affiliation, no publishing list, no professional society affiliation, papers not published in scholarly journals therefore no peer review. Probably more that I have missed. Even where the three papers were presented (PIRT 2006) looks like it would not stand up to too much scrutiny. At that point I lost interest. 73, Frank Hmmm, that is sad, so very sad ... In other words, your logic, education and reasoning powers make you highly dependent upon "rubber stamps", and, unable to think for yourself, reason for yourself, use high mental capacities--you are stuck with dependance on a "USDA stamp" telling you the "meat" of the matter is fit for you consumption? You, certainly, must be the product of this generation ... this is so unfortunate, when I was in college they taught us "how to reason", and "how to research"--NOT WHAT TO THINK, HOW TO THINK or IF IT WAS OK TO THINK ... I guess just like cheap crud made in china ... so has gone the education given to this new generation ... perhaps you could complain to the college who has turned out this "inferior merchandise?" .... sad, so very sad ... :-( Best of luck, may you find better on the path yet left before you ... Regards, JS |
#127
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![]() "Art Unwin" wrote in message ... On Nov 14, 3:11 pm, (Richard Harrison) wrote: Art Unwin wrote: nothing that answered the question.. as expected. well, art... lets try it even simpler... what term(s) in maxwell's equations specify the contribution of the weak force? maybe from that we can determine where they are implemented in art's fantasy about modeling software. |
#128
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Art Unwin wrote:
"Could you give a similar description only this time make it a 5/8 wavelength antenna." My previous resume` regarded current distribution on a 1/2-wave standing-wave antenna. A 1/2-wave antenna is resonant, that is it has no reactance, and it is open-circuited at both ends. Its feed point is in its center, at its high-current point, and it is a pure resistance. The 5/8 wavelength antenna consists of a 1/2 wavelength section of radiation resistance but no reactance plus a 1/8 wavelength section of small radiation resistance and a large capacitive reactance. To receive maximum energy, the capacitive reactance must be compensated. A unity power factor is desirable. As with the 1/2-wave antenna, current distribution in the 5/8-wave antenna is controlled by its open-circuited ends. On page 187 of the 3rd edition of Kraus` "Antennas" he says: "A sinusoidal current distribution may be regarded as the standing wave produced by two uniform (unattenuated) traveling waves of equal amplitude moving in opposite directions along the antenna." We know there`s radiation and loss as the current travels to and fro between the open-circuited ends of the antenna, but if unattenuated is good nough for most purposes for Kraus, it is good enough for me. Best regards, Richard Harrison, KB5WZI |
#129
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On Nov 15, 2:07*pm, (Richard Harrison)
wrote: Art Unwin wrote: "Could you give a similar description only this time make it a 5/8 wavelength antenna." My previous resume` regarded current distribution on a 1/2-wave standing-wave antenna. snip "We know that..........." !!!!!!! hmmmm I don't know who "we" is but for one I don't know Could you explain who "we" is and on what authority or explanation has "we": got for such an implausable statement? I do thank you for responding. Oh what a web we weave when we try.... May be this is why scientists have not yet been able to rationalize radiation and we are just left with theories with holes as in cheese. Industry shows us not just talk about it they show us every day what happens to a particle on their conveyor. They even let you show the particle levitated and revolving. Industry also shows you that eddy currents occur in a closed loop circuit and one must see that the combination of the alternating current flow and the resulting eddy current can levitate a particle. They don't just talk about it they can demonstrate it. This is much more plausable and reproduceable than wireing a house with an open circuit to plug into. Also the old books that you read on both argue that a fractional wavelength is represented by a series circuit that is not open! They also say that a full wave antenna is represented by a parallel or tank circuit and again the circuit is not open! No wonder radiation has not been explained fully when so many paradoxes are present. Oh and if my house is wired as an open circuit asit is time related why on earth would one need fuses and where would they put them if it is an open circuit? The idea of two currents opposing each other on the same surface of an open circuit where the eddy currents is thus cancelled by revolving in opposite directions and the same thing going for the time varying current tells me you have discovered the "big bang" by not placing a fuse in an open circuit. Kraus was not perfect otherwise he would have improved on his thinking during his life time by studying radiation and it's creation. Regards Art We know there`s radiation and loss as the current travels to and fro between the open-circuited ends of the antenna, but if unattenuated is good nough for most purposes for Kraus, it is good enough for me. Best regards, Richard Harrison, KB5WZI |
#130
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Richard Harrison wrote:
Art Unwin wrote: "Could you give a similar description only this time make it a 5/8 wavelength antenna." ... Best regards, Richard Harrison, KB5WZI Richard: I certainly don't want to engage in a large argument. Rather, I would just venture an opinion directly related to my real world construction experiences, and the results from the same: If there are notable gains from constructing a 5/8 wave antenna, as opposed to a 1/2 wave--I have NOT seen them. It all looks good in EZNEC and/or mmana-gal (or, "on paper"), however, in real world s-meter/signal-reports, "it" does not. Perhaps I have experienced a anomaly(s?) Or, put simply, the extra "hassle" in dealing with these extended lengths is simply "not worth it!" Regards, JS |
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