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On 7 Nov, 08:41, (J. B. Wood) wrote:
In article , Richard Clark wrote: Energy propagates much as we expect it does; power - well, not always (hardly ever). 73's Richard Clark, KB7QHC Hello, and the above statement is simply not true as any undergraduate textbook in electromagnetics will point out. Transmission lines, for example, be they 60 Hz or at RF due in fact transmit power from source to load. At any point along the line the average power is given by 1/2 the real part of the product of the voltage and complex conjugate of the current. Voltage and current contain their respective components of travelling waves in both directions (source-to-load and load-to-source). Of course the transport medium doesn't have to be a transmission line - it can be free space, say from a transmitting antenna to a receiving antenna. I have no idea how many of those in our ham hobby have taken any courses in electromagnetics (traditionally called "fields" by undergrad EE students). Oh I believe that there are quite a few who memorised what was taught and what was in the books but now they are getting older and the memory is failing where they didn't understand the basics. Since you may be younger and have taken the EE course. Try adding a time varient to Gaussian statics law and thus show how it equals Maxwell's law. But them you may be relying on memory as well and bypassed mathematics. Richard has come a long way by doing that and nobody is equiped in mathematics to call his bluff. Things were like that when I was in the military. Don't ask why just put it into the memory box and follow orders. If you can't remember then follow the rest of the squad. Doesn't that sound like ham radio? Art Such courses are part of an undergrad EE program and if you major in electrophysics (as I did) at the grad level you delve much deeper into the subject. Sincerely, John Wood (Code 5550) e-mail: Naval Research Laboratory 4555 Overlook Avenue, SW Washington, DC 20375-5337 |
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