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#1
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Art KB9MZ wrote:
"Why must only series circuits be considered for radiators?" It is convenient to follow custom. Art also wrote: "What is it about parallel circuits that make them unsuitable?" We are more familiar with impedance than admittance in most cases due to our instruction. A parallel resonsant circuit is a high impedance (low admittance). A series resonant circuit is a low impedance (high admittance). For a parallel circuit, Q=R/X. For a series circuit, Q=X/R. The series circuit has its equivalent parallel circuit. The parallel circuit has its equivalent series circuit. The mathematical conversion from one to the other is simple and shown in my 19th edition of the ARRL Antenna Book on page 24-12. (By coincidence the action of 1//4-wave and 1/2-wave transmission line sections is shown on the next page, 24-13) Commentors on using a 1/2-wave of foreign line inserted in a 50-ohm system, and what the ITT Handbook says should consult the Antenna Book or some other book that not only gives you the basic information but also tells you how to use the information. Best regards, Richard Harrison, KB5WZI |
#2
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This is silly......... and you can't blame this on web tv. Not one answer to any of the questions that anybody can hang their hat on!, Just talking out loud from a book that fell open at a page. When are you going to make some sense with your responses, most of us know and use the formulas that you keep regurgitating but only when they are relavent. Did your posting get cut short and the answers destroyed or did you forget why you are posting? There are three simple questions only. Simple answers should suffice............. if........ you know your stuff. If you find the answers to the simple questions in a book then please let me know and I can read it in context for myself and I will thank you.. When Johny Carson gave the answers first on his show and one then had to find a suitable question for it it was funny first time around only, so you should quit doing it. If you don't know the answers then it O.K. you don't have to respond if you don't know, certainly better than verbal diarrea. Art "Richard Harrison" wrote in message ... Art KB9MZ wrote: "Why must only series circuits be considered for radiators?" It is convenient to follow custom. Art also wrote: "What is it about parallel circuits that make them unsuitable?" We are more familiar with impedance than admittance in most cases due to our instruction. A parallel resonsant circuit is a high impedance (low admittance). A series resonant circuit is a low impedance (high admittance). For a parallel circuit, Q=R/X. For a series circuit, Q=X/R. The series circuit has its equivalent parallel circuit. The parallel circuit has its equivalent series circuit. The mathematical conversion from one to the other is simple and shown in my 19th edition of the ARRL Antenna Book on page 24-12. (By coincidence the action of 1//4-wave and 1/2-wave transmission line sections is shown on the next page, 24-13) Commentors on using a 1/2-wave of foreign line inserted in a 50-ohm system, and what the ITT Handbook says should consult the Antenna Book or some other book that not only gives you the basic information but also tells you how to use the information. Best regards, Richard Harrison, KB5WZI |
#3
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"Richard Harrison" wrote in message ... A parallel resonsant circuit is a high impedance (low admittance). est regards, Richard Harrison, KB5WZI Now go back to your books since your memory is poor and check out what restrictions apply. Do you ignore all connection lengths between lumped circuits. Do they say all parallel circuits ALWAYS have a high impedance without exception? Does this simple formula account for radiation ? Does a parallel circuit in macro form that radiates apply with respect to this simple formula regardless of interconnection lengths? Must all distributed passive forms be ignored and why? |
#4
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Art, KB9MZ wrote:
"Now go back to your books since your memory is poor and check out what restrictions apply." My statement was: "A parallel resonant circuit is a high impedance (low admittance)." I reaffirm that statement. It assumes a high-quality circuit. It is general and nonspecific. It is not all-inclusive. It allows exceptions. In the ideal case, only perfect inductance and capacitance comprise the circuit. Z = XL/R. As R goes to zero, Z goes to infinity. The impedance of a parallel resonant circuit is: Q(XL). Best regards, Richard Harrison, KB5WZI |
#5
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Well you are too far gone down memory lane, you are unable to focus for any
length of time and can't remember things or what you have said in the past.No wonder you keep close to books, your memory has gone. Now go back to your book and see that the high impedance comes from a parallel circuit with lumped components to which radiation is not considered and there is no length to the connections between them. It does not mean that a radiating antenna which is in a parallel configuration will have a high impedance., It can have a high impedance or even a low impedance and you must account for distributed loads in any of your calculations to determine whether it will be high or low when the bandpass array is resonant. Now you probably will not find that statement in a book so you are in the hole with no way of getting out. You just blew it and you are stuck with the statements you made including the one that states that such an arrangement violates all the laws of nature as well as remembering what post you are responding to. Or is that deliberate because you found it embarrasing to think of responding to it, as you have not got the ability to speak in fractured English like Shakespeare which allows for a lot of wriggle room. I leave it at that and maybe while you are still alive somebody will be kind to you and explain that which you cannot comprehend or if you are still around in a couple of years you may be able to read it for yourself when it is in print. I didn't really expect that you could come up with anything of detail, just words Bye "Richard Harrison" wrote in message ... Art, KB9MZ wrote: "Now go back to your books since your memory is poor and check out what restrictions apply." My statement was: "A parallel resonant circuit is a high impedance (low admittance)." I reaffirm that statement. It assumes a high-quality circuit. It is general and nonspecific. It is not all-inclusive. It allows exceptions. In the ideal case, only perfect inductance and capacitance comprise the circuit. Z = XL/R. As R goes to zero, Z goes to infinity. The impedance of a parallel resonant circuit is: Q(XL). Best regards, Richard Harrison, KB5WZI |
#6
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On Mon, 08 Mar 2004 06:11:32 GMT, "aunwin"
wrote: fractured English like Shakespeare Art, Why do you hate Brits so? 73's Richard Clark, KB7QHC |
#7
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Richard, Art doesn't dislike 'Brits', in fact he identifies with them! Art does seem to have an adversion to people who have had a formal education, (you can 'see' that from his seeming allergy to anything out of books). I don't think that Art realizes that it would be impossible for an average person to learn the present knowledge base of electronics (or most any field) by experimentation, the average person wouldn't live long enough. Reading 'those' books is a necessity, not an option. I also think, from just observing Arts attitudes from his postings, that Art has a 'problem' of a physical nature. His attitude changes periodically, and that period is fairly rhythmic. That's not a 'put down', I'm not making fun of Art. It is an easily verified observation, based on over 20 years of experience in a 'sort of' related job where I had to deal with similar people. I'm saying this with honest and well meaning intentions in the hopes that Art will do something about it, if possible. And that's it. I won't make any more comments about Art... 'Doc PS - And just as a reminder, the "Doc" has no formal meaning, it's just a nick name. |
#8
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I have often stated that I suffer from Manic Depression and some other
defects and yes some have made fun of it. But I do not work at a post office and do not carry a gun with me at all times for when I get angry. And yes I do try to control manic thoughts. I did not choose the illnes but I have chosen to live with it the best I can. It is for that reason I decided to focus on antennas as a way of removing myself from a bed. Yes it was very hard to concentrate and learn especially when reading Field and Wave books but now I can atleast venture outside and play with antennas. Now you have a fresh bunch of information to ridicule, have at it. "'Doc" wrote in message ... Richard, Art doesn't dislike 'Brits', in fact he identifies with them! Art does seem to have an adversion to people who have had a formal education, (you can 'see' that from his seeming allergy to anything out of books). I don't think that Art realizes that it would be impossible for an average person to learn the present knowledge base of electronics (or most any field) by experimentation, the average person wouldn't live long enough. Reading 'those' books is a necessity, not an option. I also think, from just observing Arts attitudes from his postings, that Art has a 'problem' of a physical nature. His attitude changes periodically, and that period is fairly rhythmic. That's not a 'put down', I'm not making fun of Art. It is an easily verified observation, based on over 20 years of experience in a 'sort of' related job where I had to deal with similar people. I'm saying this with honest and well meaning intentions in the hopes that Art will do something about it, if possible. And that's it. I won't make any more comments about Art... 'Doc PS - And just as a reminder, the "Doc" has no formal meaning, it's just a nick name. |
#9
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Art, KB9MZ wrote:
"It does not mean that a radiating antenna which is in the parallel configuration will have a high impedance." Parallel configuration can mean several things. I will take it to mean the antenna shares some of the characteristics of a parallel resonant circuit. Experience is that an end-fed 1/2-wave antenna has a high feedpoint resistance while an end-fed 1/4-wave antenna has a low feedpoint resistance. Since Art is hunting discrepancies, 1/2-wave and 1/4-wave are only approximate wavelengths. Resonant lengths in an antenna are shorter than free-space wavelengths due to reduced velocity along a wire and due to capacitive effects near the open-circuit at the end of the wire. For a given power input to the antenna, the feedpoint voltage rises as the feedpoint impedance rises. See Ohm`s law. In 1949 I worked in a broadcast plant where two stations shared the same tower. Both had frequencies, 950 KHz and 1320 KHz, that were higher than the 1/4-wavelength frequency of the tower which was designed for the previous occupant of the plant. Its frequency was around 740 KHz. The 1/2-wave resonant frequency of the tower might have been around 1480 KHz. The high length of the tower was still enough to make it a high impedance at its operating frequencies. 1320 KHz is emanating from that that tower as I type. It is hot as a pistol. Big arcs can be drawn at the base of the tower. Art`s question was: "What is it about parallel circuits that makes them unsuitable?" Like Johnny Carson, I may have given the answer before revealing the Question. A parallel resonant circuit shares the high impedance trait with an end-fed wire near 1/2-wave long. A series resonant circuit shares the low impedance trait with and end-fed wire near 1/4-wave long. A 1/4-wave series resonant circuit antenna with an open-circuit end produces a low impedance at its driven end through an impedance inversion caused by the reflected energy arriving back at the drive point. Radiation and other resistance prevent the reflected wave from causing a complete short-circuit at the drive point. When I say a radiating antenna in the parallel configuration (Art`s words) will have a high impedance (the 1/2-wave repeats high impedance caused by the open circuit), it will mean that its radiation resistance has grown with its length and its reactance will be zero if the antenna length has reached 2nd resonance, or the reactance is non-zero between resonant lengths. High and low are relative terms. The questions should be, how high? or how low? Best regards, Richard Harrison, KB5WZI |
#10
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"Richard Harrison" wrote in message ... Art, KB9MZ wrote: "It does not mean that a radiating antenna which is in the parallel configuration will have a high impedance." Parallel configuration can mean several things. I will take it to mean the antenna shares some of the characteristics of a parallel resonant circuit. So now 'WILL' can now be read as 'CAN' with respect to impedance 'EXCEPT' in the case of circuitry where radiation is ignored At last,..... at last.... even tho grudgingly. So now you cannot use that as a reason for me to lie about my having an antenna in parallel form You CAN have a low resistance of 1 ohm or you CAN have one 1000 ohms so play your silly games about me being a lier, don't hold your breath, have no integrity and also a thief, all of which have been thrown at me because I stated I have a rotatable beam for 160 meters that has a moveable 5 khz pass band. Now you have the problem of explaining to people that you can have a parallel arrangement for an antenna and we were wrong to focuss on the high impedance aproach to accuse Art of lying and all the other accusations that was thrown at him. Now ask the people involved why they refused to check for themselves or do they have a backup technical augument. You made a point about the loop dipole well the patent office accepted it as viable even tho my writing was not clear because they had a samplke. The University of Illinois accepted it for review ( Yes I spoke also to the professor of Log periodic fame as well, very interesting person) The antenna director in charge or general Boss stated my claims were confirmed. So the antenna experts in this group don't understand how it functions so immediately get in to gear to attack. Didn't Walter lead the last attack on a guy, any attempt to squash inovation. Now I can rest peacefully seeing that you are exposed for what you are. Now when you see the next antenna in print you can chant what all followers say....Well I knew that all the time, at least that is my experience when I come up with something. The problem is that some people get degrees by choice of multiple answers with a circular sweep of a pencil to make a dot, first principles don't matter diddly as it is in a book written just like that.. |
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