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On Fri, 05 Mar 2004 01:24:04 GMT, "aunwin"
wrote: That is the longstanding convention. Same thing applies to a one wavelength dipole. All such are the basis of the J-Pole and the Zepp (when you strip away their matching sections). Well that is new to me, I never consider the matching circuit as part of an antenna but only a required band aid. Can you point me to where this is discussed ? ( J pole I know nothing about but the others I would like to read of what you refer to as a parallel circuit) This could be the point of confusion. The archives are rich in this discussion. The following quote from me covers it adequately: Matching sections to the J-Pole and the Zepp are contributors to radiation due to the unbalanced nature of those antennas designs. How much they contribute is perhaps arguable, but when they are built in without care, their contribution cannot be denied. The matching circuits contain both circulating currents and common mode currents. The common mode currents, as a function of the physical length compared to wavelength, offer radiation. The radiation may aid, or it may hinder, but it is there none the less. Not sure if you are saying 'yes'. I personaly think it is a parallel circuit to which I would answer 'yes'. No, they are NOT parallel - they could be, but there is nothing inherently parallel and it all depends on the drive and load applied. Well on that note I see a dipole as a single series circuit fed by a generator( ARRL book), where-as I see a bandpass circuit as a parallel circuit. This is a product of your shortfall of experience and instruction. I can construct a bandpass circuit using only resistors and capacitors. There is NOTHING resonant there. I can build a notch filter (the opposite of a bandpass filter) with a parallel circuit and EVERYTHING is resonant there. I can build a bandpass filter with a series resonant circuit. It is all a matter of connections, the topology as has been pointed out. Read the ARRL book on antennas and they dwell on series circuits as in dipole, why the big difference with this newsgroup? I have observed absolutely no discussion that would deny a series resonant analysis of a half wave dipole. Your comments seem to rotate about phase changes more than it does about coupling as to the main focal point. I have commented in no way, shape, or form about phase. It is wholly inappropriate to the topic. No comments on your other posting yet .(pro and con) which suggest the experts are unified on your statements. As if I cared.... Engineering is not a democracy. I will have to choose my words very, very carefully tomorrow on that one.Up to now I feel fully exposed on what I don't know that which every body else knows Them? Hardly. Few dwell on these matters as there is a script in the amateur rags that offer equivalent circuits presented at the drive point for various length radiators. The point at which you may go seriously off the track is to interpret those equivalent circuits into physical structures of an over-strained imagination. It is fine and well to simply observe that the full wave dipole has an equivalent with a parallel resonant circuit. It is vastly different to assign the physical elements of the structure of the antenna to roles of capacitor, inductor and so on to make that parallel circuit "real." 73's Richard Clark, KB7QHC |
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