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#1
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![]() "Szczepan Białek" wrote in message ... "Richard Clark" wrote ... I won't wait for that obvious failure. This is several steps above your pay-grade. So, you should really attempt to work on first principles rather than rummaging in the attic for impressive artifacts of science. And what should do Richard Harrison who wrote: "At the open circuited ends of a resonant antenna there is almost double the forward voltage but zero total current due to cancellation of the dorward and reflected currents at the open circuit. At the open circuit in the wire, all the energy in the wave is transferred to the electric field. " S* What Richard wrote is correct, if written in a slightly provocative manner (deliberately?). But he wasn't stating that the electric field 'At the open-circuited ends of a resonant antenna' passes energy into a radiated radio wave. The energy that makes it that far (i.e. isn't radiated on account of current in the element) is stored temporarily in an 'electrostatic' field which is one of several 'reactive' or 'induction' field components that surround a dipole antenna and decay with distance much faster than the radiation field components (i.e. those that make up a radio wave). As I've noted before, the term 'electrostatic' should not be interpreted literally as an unchanging field - it is used to differentiate between the reactive components and the radiation components of electric field - if this offends you, just call it a 'reactive' component of electric field. This stored energy is passed back into the antenna during the following RF quarter cycle. And guess what ... one of the reactive field components is longitudinal! .... but it isn't part of a radio wave - both parts of a radio wave, the magnetic field and the attendant electric field, are directed transverse to the direction of propagation, but now I'm repeating myself from a week or more ago. Power cannot be abstracted from the reactive fields, including the longitudinal one; they affect the imaginary part of the terminal impedance of the antenna. Of course, I expect you will contradict all this but I still recommend that you read a proper account of the fields around a dipole rather than making up your own version. Since you appear to have a phobia of libraries, you could buy a second-hand copy of Kraus, Antennas for only $15 online: http://www.abebooks.com/servlet/Sear...nnas&x=55&y=10 and there are many, many other sources. Failing that, you could always search the web for a bootleg copy, or one of the MIT Radiation Laboratory series of books. I don't condone bootlegging but someone in another newsgroup recently gave a link to a collection of illegal copies and, in the hope of ending these ridiculous arguments, I'll pass on what he wrote: http://cer.ucsd.edu/~james/notes/MIT...diation%20Lab/ Chris |
#2
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![]() "christofire" wrote ... "Szczepan Białek" wrote in message ... And what should do Richard Harrison who wrote: "At the open circuited ends of a resonant antenna there is almost double the forward voltage but zero total current due to cancellation of the dorward and reflected currents at the open circuit. At the open circuit in the wire, all the energy in the wave is transferred to the electric field. " S* What Richard wrote is correct, if written in a slightly provocative manner (deliberately?). But he wasn't stating that the electric field 'At the open-circuited ends of a resonant antenna' passes energy into a radiated radio wave. Look at this: ""At the open circuited ends of a resonant antenna there is almost double the forward voltage". "Almost double voltage" is like the pressure in the Kundt's tube. The energy that makes it that far (i.e. isn't radiated on account of current in the element) is stored temporarily in an 'electrostatic' field which is one of several 'reactive' or 'induction' field components that surround a dipole antenna and decay with distance much faster than the radiation field components (i.e. those that make up a radio wave). As I've noted before, the term 'electrostatic' should not be interpreted literally as an unchanging field - it is used to differentiate between the reactive components and the radiation components of electric field - if this offends you, just call it a 'reactive' component of electric field. This stored energy is passed back into the antenna during the following RF quarter cycle. And guess what ... one of the reactive field components is longitudinal! ... but it isn't part of a radio wave - both parts of a radio wave, the magnetic field and the attendant electric field, are directed transverse to the direction of propagation, but now I'm repeating myself from a week or more ago. Power cannot be abstracted from the reactive fields, including the longitudinal one; they affect the imaginary part of the terminal impedance of the antenna. Of course, I expect you will contradict all this but I still recommend that you read a proper account of the fields around a dipole rather than making up your own version. It is not my version. The electrons were discovered 100 years ago. Since you appear to have a phobia of libraries, you could buy a second-hand copy of Kraus, Antennas for only $15 online: http://www.abebooks.com/servlet/Sear...nnas&x=55&y=10 and there are many, many other sources. I am sure that there is all about electrons. It is not easy to read with understanding. Take a glance once more and try to find compressible electrons. Failing that, you could always search the web for a bootleg copy, or one of the MIT Radiation Laboratory series of books. I don't condone bootlegging but someone in another newsgroup recently gave a link to a collection of illegal copies and, in the hope of ending these ridiculous arguments, All arguments are from this Group posts. I'll pass on what he wrote: http://cer.ucsd.edu/~james/notes/MIT...diation%20Lab/ S* |
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