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Steve I thank you for your response and I am beginning to see and have
confidence in what I am saying alss I believe I over explained things which really created problems. Energy alonf any member travels at the speed of light wether the member or element is straight or converluted. In a straight member the current under goes a phase change at all times thus from one direction the current varies according to I Cos Phi i.e. accellerating in value and decellerating in value. When the same electric current follows a coiled load there is no phase change and the curreny does diminish slightly due to resistance loss and the effect of inter coil and capacitance w2hich vastly affects the impedance as the current moves around the coil.. because there is no phase change and if we are able to remove the rising inductance and capacitance created by the close proximety of coils we can then attain a resistive value of impedance or at least progress to that end. Thus when you travel around a single coil you are not affected by the inductance and capacitance in a wound coil so the question is how to achieve this without a closed loop. What I did before was to use a small number of open coils made from 1/2 corregated copper transmission line and placed them at various heights as required by my programing where it provided a very large bandwidth. So what you may ask, what were your measurements! So I decided to use upto 20 loops attached to a 40 foot fibreglass tubing tower. This required a program containg over 400 segments plus 20 variable dimensions to cover the various distance between loops and where I predecided on the loop diameter. So you can see that for this many loops in series makes for a very long program and with the extra checking I must do so that prior trends are duplicated. All of this isw intended to produce a vertical for a band below 20 metres where its actual height and signal strength will be proof of the pudding. Thanks again for staying with me and for your advice. I will definitely keep you informed if the results mirror my previous tests. I have the tower and I have made the loops and just need one more overcheck on yhis very long program. Somewhere in between I will work on this laptop so it will provide readable script and also transfer my computor program. Very best regards Art Unwin KB9MZ......XG Bloomington ILL "Steve Nosko" wrote in message ... [... snipping all the agreed to parts so far...Sorry, but all the history is just too much.not to mention what follows! .. . . . . . . . ] ALSO, ART. PLEASE do something to make your responses obvious in the body of text, like line spaces, or lots of asterisks or something so I can find your responses. ***** maybe like this Also, you can use a word processor to compose these messages and get the benefit of a spel chek. Hi hi , I am right now, then Cut & Paste into your news-reader. On to the topic. Steve said: So, if we change the velocity direction (to always be tangent to the circle) , but not the magnitude (or speed), then we have acceleration - what we call radial acceleration. Art: Not sure if I follow that. Steve: I am only describing what it takes to get motion around a circle. It is basic physics. I'll try saying it several other ways: The "thing" which represents the acceleration that is causing the movement in a circle _IS_ a vector pointing toward the center of the circle. The object is being accelerated toward the center of its orbit. Its acceleration _IS_ directed at the center. Another way to say it is; "In order to get the thing to travel in a circle, you must accelerate it toward the center of said circle and this acceleration is caused by a constant force toward the center and can be represented by a vector pointing toward the center. Good old F = MA is also a vector equation. That is, it can be used to account for the direction of forces and accelerations. If the force is in a given direction, then the acceleration is also in that same direction. (a logical conclusion is that the acceleration is also changing in order to remain pointing at the center as the thing moves around the circle) It appears that you call the acceleration one thing and the vector another, but they are the same thing, not two different things. So it appears to me that you are trying to make the vector something else, or something new to get some new effect. This is where I am confused as to just what you are thinking is the effect. [...skipping ahead, some, but basically repeating in new terms ...] ART: I am saying that energy is inputed to maintain constant speed which can be seen as creating a CONSTANT force vector at a tangent. Steve: Yes, (in _uniform_, or constant circular motion) it takes a constant inward force to get the constant inward acceleration which results in the constant circular motion. HOWEVER, I have a SERIOUS problem with this word "CONSTANT" in this context - I address below. Steve: Moving away from the basics of uniform circular motion and on to RF in a wire. ART: Yes because when the radiator is straight it is phase change that creates cyclic current change ala accelleration. Steve: OK, so we are back to this electron flow in a straight wire following the sinewave in current, or "cyclic current change ", to use your terms. Sure. I don't under your cause and your effect here because I do not understand what it is that you refer to when you use the words "phase change". It is the _generator_ (or transmitter) which is causing the current and all the acceleration(s)...many per second. The generator produces EMF or voltages which alternately drive current first one way, then the other, in this sine wave fashion - along the wire. EMF (Electro Motive Force) is call this because it acts like a force to move electrons (causing current) in the wire. It is this force which causes the accelerations and motions. The generator accelerates the electrons, not what you call "phase change"--I don't know what this means. There is a change in _current_ over time, but NOT phase. Art: In the case of a circular radiator I understand that there is no phase change a nd the radiation vector is a constant. This may well be the nubb of the misunderstanding. Steve: I think there is a definite nubb here! You appear to have jumped to DC away from RF. We should be talking about the SAME type of varying current, therefore there is still the sinewave form of current flow, the same accelerations. We do have an added velocity change around the circle, but we haven't taken away the sinewave of current Steve: I also think you are wondering if this radial acceleration does some special radiation that is different from the radiation of the charge simply. ART: That is correct in that current variation is constant in one case and cyclic in the other Steve: First, I wouldn't use phrases like "current variation is constant". Either there is a variation, or it is constant. This phrase implies that something is varying in a very repeatable or constant manner, like a sine wave or square wave or triangle wave. To answer the content of this comment, most emphatically NO! There is always the cyclic, sinewave variation in current when you bend a current carrying conductor into a circle. The AC sine wave doesn't go away. Steve: I skip the area under the curve comment and continue with comments on your cosine reference. ART: Yes I see the phase change as shown by the current curve. Steve You gotta drop this "phase change" phrase. I think you simply mean the voltage change over time, meaning the sine wave of current that is a given in this situation. ART: and in the case of circular motion I do not see a phase change ( I cos phi ) Ahhhh! OK, perhaps this direction will help. Lets talk about your formula I COS(phi) which is, of course I*COS(phi). This formula gives the current at any _instant in time_ when you plug-in that value of time. However, "phi" is NOT one number. This is actually I*COS(wt) that's omega times "t". This is the formula, or mathematical function of the sinewave of an AC signal of constant frequency.just what we are talking about. This is "I", which is the peak magnitude of the current under discussion, times the cosine of the angle given by multiplying the frequency (omega) by the present value of time - Which is CONSTANTLY INCREASING as time progresses! This means that the current is constantly changing. If you plot these values versus time on a graph, you see our friend the sine wave and the tops and bottoms are exactly "I" high (away from zero). Steve: You keep mentioning "constant speed" yet we are talking, I thought, about an antenna with RF current in it. ART: Yes STEVE: If this is the case, there is _NO_ constant speed of the current. It is constantly varying in a sine wave. It has a sinusoidal speed variation and therefore a sinusoidal acceleration Yes I agree. That would be of the value I cos phi with cos phi providing the sign wave. I believe we are saying the same thing STEVE: Then I am unable to understand where you are going. I see nothing new ( in regards to the basic physics above) created by the antenna being in a circle. We just have AC flowing in a circle. Some of the problem is your un conventional use of the terminology which makes the transfer of the underlying concepts & ideas difficult. It is ok to not be formally schooled in a subject. You can be what we call "self-educated", but you must learn to use the terminology in he correct ways (according to the way the vast majority of us use it) or you won't be able to make yourself understood or understand others. Like I tell my students, you MUST learn the terminology and use it correctly--- while in both cases your head may really hurt, there is a world of difference between a headache and a subdural hematoma! ART: It may well be a difference of terms applied but I am pleased you follow the main drift of what I was saying so you could be well armed to correct me where I was wrong. Steve: You go on to describe what seems to be an antenna composed of several large horizontal, circular, or perhaps better described as helical, elements stacked one above another, where some are wound in right-hand sense and others in left-hand sense. I'll not go there because I believe you are looking for some kind of a new phenomenon which is the result of this arrangement. This may sound elitist, but I believe you are trying to discover new physical principles with limited knowledge of the physical world. It appears to me that your limited knowledge and ability to put concepts to words leads you to believe there is a magic bullet just waiting to be stumbled upon and that you can do it. Antennas, past the simple dipole (although the basics of radiation is a great source of confusion in itself) get complex really fast. A firm understanding of how the currents in all parts of an antenna cause remote fields that superimpose to cause the total, resulting field is critical to being able to devise new and improved antennas, if they exist. Go ahead and have fun modeling antennas. See what comes out of various configurations. I recommend starting out simple to give yourself some understanding of 'what' causes 'what'. Using this, build a model in your brain (one that suits you) which ALWAYS explains all the observer phenomena as you move along. Your model must NEVER violate any laws of physics or fundamental principles which are known to be true. All this must also make sense or "fit" when viewed with all other fundamental concepts, but understand that much will be mysterious to you without this understanding. I applaud your desire to learn and experiment, while I am sad that you have insufficient background preventing you from seeing some of the real beauty of the natural phenomena we call electronics. My very best regards to you and thanks for hanging in there as opposed to a derogatory comment Art. It saddens me when I read some of what is posted. Hams are generally a very friendly lot, but the Internet (UseNet in particular) somehow releases the evil in some. We all have our weaker moments. Some of us are just a lot closer to them than others. All I can do is a Tsk, Tsk and move on. I must lead my life to a higher standard. It's a dirty job, but somebody's got to do it. Some people go to church and then cut you off and swear at you in traffic. I don't do either any more. 73, Steve |
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