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Is resonance really where you get best antenna performance?
- Thread starter The DB
- Start date
"Is resonance really where you get best antenna performance?"
the importance of resonance in an antenna system:
1.optimizes current and voltage.
2.makes the antenna much easier to feed.
3.indicates frequenc/y/ies where the load represents a pure resistance.
4.establishes the center of the band in reference to operational bandwidth
5.tracking changes in antenna systems due to modifications, weather, etc..
6.tuning for X=0 provides correction for any and all velocity factor error.
7.provides a reference frequency for determining antenna "Q" factor.
the importance of resonance in an antenna system:
1.optimizes current and voltage.
2.makes the antenna much easier to feed.
3.indicates frequenc/y/ies where the load represents a pure resistance.
4.establishes the center of the band in reference to operational bandwidth
5.tracking changes in antenna systems due to modifications, weather, etc..
6.tuning for X=0 provides correction for any and all velocity factor error.
7.provides a reference frequency for determining antenna "Q" factor.
So you quote a question, and then don't bother to actually try and answer the question. Instead, you use distractions that have nothing to do with what was being asked or discussed...
I get it, you are a true believer, and that belief must not be questioned. Ever. Period. End of Story. Now if only you could find any actual evidence...
I could take the time and address these point by point, but you won't bother reading any of it anyway, and you are as accurate as you typically are when posting such a list, actually, in this case some are actually related to resonance, indirectly, so you actually did better than usual. But none of your lines could be said to be completely accurate. And, of course, as usual there is a wtf line, or posting something that is completely irrelevant as part of said list...
The DB
I get it, you are a true believer, and that belief must not be questioned. Ever. Period. End of Story. Now if only you could find any actual evidence...
I could take the time and address these point by point, but you won't bother reading any of it anyway, and you are as accurate as you typically are when posting such a list, actually, in this case some are actually related to resonance, indirectly, so you actually did better than usual. But none of your lines could be said to be completely accurate. And, of course, as usual there is a wtf line, or posting something that is completely irrelevant as part of said list...
The DB
One (or two) things I'm not seeing and real answers to, are the very two problems raised in any install.
Making any system show a low SWR - requires some form of transformation.
So there the one issue back at post #35 about the "non-resonate" (ping reference) so SWR may not be the best at the given frequency because of the elements are not properly sized.
And the other...
Being the true feedpoint impedance - that in one post #13 - you cannot just make an assumption for this ...
For this would make any magnetic mount - or even a resonate 1/4 wave vertical even physically mounted and grounded - as unable to qualify to even be considered viable - yet people use these things every day.
So to me, "Generalities" are nice to help other understand, but @The DB went thru a whole process you seemed to missed a few points on - one glaring event is we have the ability to generate any antenna thru models but the equipment used to connect these requires the use of some type of transformation to obtain 50 ohms that we can get a "generalized" overview that by a low SWR it must mean it's good.
It depends on the old adage...
Sometimes you're the Bat - Sometimes you're the Ball.
It just seems a little unfair that @The DB gets brushed off without ever looking in why does the world need low SWR - is it for the efficiency or because whomever maketh the coax - determines the fate of what everyone else must use...Or would it be more polite to presume that those that MUST require a LOW SWR - do so to avoid a warranty violation issue - more so than to say - "Hey - this coat hanger really works - you should try it!"
Making any system show a low SWR - requires some form of transformation.
So there the one issue back at post #35 about the "non-resonate" (ping reference) so SWR may not be the best at the given frequency because of the elements are not properly sized.
And the other...
Being the true feedpoint impedance - that in one post #13 - you cannot just make an assumption for this ...
For this would make any magnetic mount - or even a resonate 1/4 wave vertical even physically mounted and grounded - as unable to qualify to even be considered viable - yet people use these things every day.
So to me, "Generalities" are nice to help other understand, but @The DB went thru a whole process you seemed to missed a few points on - one glaring event is we have the ability to generate any antenna thru models but the equipment used to connect these requires the use of some type of transformation to obtain 50 ohms that we can get a "generalized" overview that by a low SWR it must mean it's good.
It depends on the old adage...
Sometimes you're the Bat - Sometimes you're the Ball.
It just seems a little unfair that @The DB gets brushed off without ever looking in why does the world need low SWR - is it for the efficiency or because whomever maketh the coax - determines the fate of what everyone else must use...Or would it be more polite to presume that those that MUST require a LOW SWR - do so to avoid a warranty violation issue - more so than to say - "Hey - this coat hanger really works - you should try it!"
Wow, what a terrible attempt at trolling. I see the post you are responding to four pages ago, and of course, like a typical troll, you didn't even bother to link to it. Go figure.
Physically, yes, no argument there, but physical length is not necessarily the same as electrical length. To get from using your tape measure to the part you don't know, take apart the fiberglass sections, behind one of them there is a capacitor, as measured by a member on this forum a 42 pF capacitor... Now factor the effects of this capacitor into the antenna's electrical length. I'll wait...
The DB
Physically, yes, no argument there, but physical length is not necessarily the same as electrical length. To get from using your tape measure to the part you don't know, take apart the fiberglass sections, behind one of them there is a capacitor, as measured by a member on this forum a 42 pF capacitor... Now factor the effects of this capacitor into the antenna's electrical length. I'll wait...
The DB
LOL I am sorry, I am confused as you must be talking to someone else about the troll comment??? This is a forum...just speaking my opinion.
Now, I am pretty sure there is a healthy 22+ feet of wire after that capacitor but you can sit here and tell me it's whatever wavelength you want too....I'll sit here and laugh. Save the reply, not playing the game man
Really, no-one is playing.
There is more going on than just a tape measure can tell you.
DB has plenty of experience playing with antennas, and modeling them, you might read some of his other post's on the forum.
73
Jeff
There is more going on than just a tape measure can tell you.
DB has plenty of experience playing with antennas, and modeling them, you might read some of his other post's on the forum.
73
Jeff
Like I said in my original post. That 22' of wire sure seems 5/8 to me...
I guess that makes me a troll because I don't agree with one's personal opinion. (sad)It it's all about that x. If you have x=0 and low swr that's great. However all that can be and you might be shooting straight up to the clouds or straight down the mast to the ground. I think it's a balance between x and take off. 5/8 should require a groundplane. Have you a ground plane? And if you put it over a groundplane it will prob mess up the rest of the numbers.Like I said in my original post. That 22' of wire sure seems 5/8 to me...
Just my thoughts
Like I said in my original post. That 22' of wire sure seems 5/8 to me...
See.....There's the miscommunication....There's a difference between opinion and structured, proven fact, DB is giving facts but because you don't understand it, you just chalk it off as an opinion. There's inductance and capacitance in every length of wire and the amount depends on the wire size and type. 22' of stranded will have a different value than 22' of solid. Silver plated, a different value than unplated copper. 18awg will be different than 14 or 22awg. If it were as simple as just cutting a piece of wire a certain length, we wouldn't have 2000 different 1/4-5/8 wave antennas, would we? You need to know the characteristics of the wire being used in order to build an optimum antenna from it. Also, if it were that simple, people wouldn't have written no less than 100 books on the subject matter.
It was what, six years ago I did the initial modeling on this? Marconi made some models as well. Unfortunately my models were lost due to a hard drive crash, well two drive crashes that were a few minutes apart from each other the second one killing my backup, but the threads are still here.
The capacitor was something like four or five feet up from the antenna's feed point I think? I recall it was in the bottom section, and it did make a difference in the radiation pattern of this antenna, although not necessarily a very big difference, it was enough to be noticed. It also changed the current distribution of this antenna, making it so this was one of two antennas I am aware of that are commonly called 5/8 wavelength where the currents are completely in phase along the entire radiator. Mind you I am remembering several threads from when this was discussed in back in what, 2016?
Maybe when I get a chance I'll model this antenna again... As the size and position of the capacitor were very specific, I'll have to go dig up the exact location. It would be good to have some models I can directly refer to when this comes up again in the future...
@Chris120 a piece of advice.
You referred to, without a quote, a comment made by me four pages ago in this thread, something that was not discussed by anyone since, and something you clearly took out of context. In the end, when you act like a troll, don't be surprised when people call you out for it. I mean, what am I supposed to think? Finally, if what I said was so wrong, didn't you find it strange that no one else, in four pages worth of posts, said anything about the Imax since?
Should you have any questions on why I said what I said, about anything really, feel free to ask. I have said many things in the past that many people would consider strange, I am happy to explain why I said what I said. But you didn't do that, you tried to make fun of something that, with all due respect, you don't understand as well as you think you do.
The DB
The capacitor was something like four or five feet up from the antenna's feed point I think? I recall it was in the bottom section, and it did make a difference in the radiation pattern of this antenna, although not necessarily a very big difference, it was enough to be noticed. It also changed the current distribution of this antenna, making it so this was one of two antennas I am aware of that are commonly called 5/8 wavelength where the currents are completely in phase along the entire radiator. Mind you I am remembering several threads from when this was discussed in back in what, 2016?
Maybe when I get a chance I'll model this antenna again... As the size and position of the capacitor were very specific, I'll have to go dig up the exact location. It would be good to have some models I can directly refer to when this comes up again in the future...
@Chris120 a piece of advice.
You referred to, without a quote, a comment made by me four pages ago in this thread, something that was not discussed by anyone since, and something you clearly took out of context. In the end, when you act like a troll, don't be surprised when people call you out for it. I mean, what am I supposed to think? Finally, if what I said was so wrong, didn't you find it strange that no one else, in four pages worth of posts, said anything about the Imax since?
Should you have any questions on why I said what I said, about anything really, feel free to ask. I have said many things in the past that many people would consider strange, I am happy to explain why I said what I said. But you didn't do that, you tried to make fun of something that, with all due respect, you don't understand as well as you think you do.
The DB
No, you have a attitude problem.
There is much more experience here than you think, but you just seem to think your tape measure is all there is to antenna design and theory.
73
Jeff