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#111
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The earth
"Jeff" napisal w wiadomosci ... You are ordering me to read the above. Why you do not read it. There is wrote: "A further feature of the structure of negative coronas is that as the electrons drift outwards, they encounter neutral molecules and, withelectronegative molecules (such as oxygen and water vapor), combine to produce negative ions. These negative ions are then attracted to the positive uncurved electrode, completing the 'circuit'.". From: Negative coronas. Mechanism. http://en.wikipedia.org/wiki/Corona_...gative_coronas "The difference, then, between positive and negative coronas, in the matter of the generation of secondary electron avalanches, is that in a positive corona they are generated by the gas surrounding the plasma region, the new secondary electrons travelling inward, whereas in a negative corona they are generated by the curved electrode itself, the new secondary electrons travelling outward." "in a negative corona the electrons are generated by the curved electrode itself". Is the field electron emission from the tip top of antenna or not? S* Yes it is, but the effect being talked about is corona discharge, and has nothing to do with the wanted radiation of radio waves. It is an *unwanted* effect on normal antennas, and occurs when the voltage at certain points gets high enough to cause ionization of the air. I repeat it is normally an *UNWANTED* condition on a normal radio antenna used for communication. And the "normal" remedy for it is the earth/chassis/couterpoise. S* |
#112
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The earth
On Apr 17, 3:41*am, Jeff wrote:
Corona discharge has nothing to do with grounding, it is purely due to the peak voltages seen at, (usually), the tips of the elements. To what are those peak voltages referenced? -- 73, Cecil, w5dxp.com |
#113
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The earth
I doubt that he is a troll. Trolls usually show some intelligence in
adapting their responses, so as to keep the fun going. This one simply fixates on a few sentences and appears unable to focus on anything out of the immediate context of the original sentence. This inability to shift focus to process new information is more a symptom of a cerebral handicap, something like Alzhheimer's or Asperger's diseases or even early-stage dementia. Unfortunately, there is not a great deal that medicine can do for these problems. Perhaps his keepers give him a computer to occupy his attention. Internet newsgroups are wonderful (IMO), but there are not good mechanisms to prevent one or two people from destroying an otherwise excellent group. One can plonk the offender(s), but that still leaves all the responses visible. I wish people would simply cease responding to him, since it is a pointless exercise. Bill |
#114
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The earth
"Bill Ogden" wrote in message
... I doubt that he is a troll. Trolls usually show some intelligence in adapting their responses, so as to keep the fun going. This one simply fixates on a few sentences and appears unable to focus on anything out of the immediate context of the original sentence. This inability to shift focus to process new information is more a symptom of a cerebral handicap, something like Alzhheimer's or Asperger's diseases or even early-stage dementia. Unfortunately, there is not a great deal that medicine can do for these problems. Perhaps his keepers give him a computer to occupy his attention. Internet newsgroups are wonderful (IMO), but there are not good mechanisms to prevent one or two people from destroying an otherwise excellent group. One can plonk the offender(s), but that still leaves all the responses visible. I wish people would simply cease responding to him, since it is a pointless exercise. Bill Hello Bill. Thanks - you said it and I thought it. He seems to copy phrases and paste them without understanding what they mean. I still reckon we had a good discussion about aerials. Regards, Ian. |
#115
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The earth
"Rob" napisal w wiadomosci ... Szczepan Bialek wrote: At transmitting you have the deficit and at receiving the excess. Without the earth the static build up and radio stop working. How would you know that when you don't even have a transmitter? But my "friend" Marconi had a lot. He wrote: "but in my opinion no practical system of wireless telegraphy exists where the instruments are not connected to earth." You will transmit just fine if you have the ground/chassis/counterpoise. S* And without it, fine as well. It is not true. You know that. S* |
#116
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The earth
Szczepan Bialek wrote:
You are ordering me to read the above. Why you do not read it. I did read all that and more when I went to school and took electromagnetics classes. snip quotes from Wiki Is the field electron emission from the tip top of antenna or not? No. You obviously did not read the information or did not understand it. |
#117
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The earth
Jeff wrote:
Is the field electron emission from the tip top of antenna or not? Yes it is, but the effect being talked about is corona discharge, and has nothing to do with the wanted radiation of radio waves. It is an *unwanted* effect on normal antennas, and occurs when the voltage at certain points gets high enough to cause ionization of the air. I repeat it is normally an *UNWANTED* condition on a normal radio antenna used for communication. Jeff What happens on antennas is NOT "field electron emission" by the modern definition of the term. Corona discharge is something else, related, but something else. |
#118
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The earth
Szczepan Bialek wrote:
And the "normal" remedy for it is the earth/chassis/couterpoise. S* No, it is not. |
#119
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The earth
"Szczepan Bialek" wrote in message ... "Rob" napisal w wiadomosci ... Szczepan Bialek wrote: At transmitting you have the deficit and at receiving the excess. Without the earth the static build up and radio stop working. How would you know that when you don't even have a transmitter? But my "friend" Marconi had a lot. He wrote: "but in my opinion no practical system of wireless telegraphy exists where the instruments are not connected to earth." You will transmit just fine if you have the ground/chassis/counterpoise. S* And without it, fine as well. It is not true. You know that. S* Hello chaps. Several of you have said that Szczepan seems unable to accept new ideas. I see that he persists in believing Marconi's comment that an earth connection is necessary. Those of us who use Yagi , loop or dipole aerials know, through experience, that an earth connection is not necessary. I am undecided why he prefers to believe the opinion of someone who worked in the early days of radio rather than those of us who use radio in modern times. I feel it is awkward to say that Marconi was wrong even though we now know this is the case. Personally, I'd say that Marconi's opinion that "no practical system of wireless telegraphy exists where the instruments are not connected to earth" obviously related to his own use of wireless. As I understand it, Marconi's aerials were not resonant at the frequency he was using. They would therefore be a mis-match to his radios and this situation was alleviated by using connections to earth. I find it puzzling that Szczepan feels happy to ignore our comments and continue to accept Marconi's opinion given that he (Szczepan) said that a transmitter is a "black box" to him. I've speculated that his English may not be very good but I shall be amused if we find out that his first language is English despite his non-English name. He never answered my question about resonant / non-resonant aerials so I guess his technical knowledge is limited. Kindest regards to all, Ian. ps: If Szczepan is happy to constrain his knowledge to the days of Marconi then I wonder how come he is using a computer. Didn't have those in the days of Marconi. |
#120
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The earth
Szczepan Bialek wrote:
A loop antena have the antinodes. The points at which electrons could "fly off". Yet they do not. See Fig. 2: http://www.antiquewireless.org/otb/lodge1102.htm Why? A lot more has been learned since 1887. snip Can you measure the static electricity? Sure, with a static meter. Yet another device that didn't exist in 1887. You will transmit just fine if you have the ground/chassis/counterpoise. It depends on the type of antenna. If it is a dipole, yagi, log-periodic, sturba curtain, rhombic, parabolic, helix, loop, cubical quad, on any of many, many more types of antennas that have no place or need to connect a ground, it would not. |
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