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Antenna optimization
Is there a software which can design an antenna (like EZNEC or similar )
then allows to automatically optimize its dimensions according to given requirements: max gain, F/B, min swr... and accepted dimensional parameters changes: boom length, spacing.... JC |
Antenna optimization
Yes!
I think EZNEC has a optimization function as you stated. I know 4NEC2 does as I have used it many times.. Cheers Bob VK2YQA JC wrote: Is there a software which can design an antenna (like EZNEC or similar ) then allows to automatically optimize its dimensions according to given requirements: max gain, F/B, min swr... and accepted dimensional parameters changes: boom length, spacing.... JC |
Antenna optimization
"JC" wrote in message ... Is there a software which can design an antenna (like EZNEC or similar ) then allows to automatically optimize its dimensions according to given requirements: max gain, F/B, min swr... and accepted dimensional parameters changes: boom length, spacing.... JC ---------------------------------------------------------------------- ------- Dear JC, You don't need software. What you describe is non-existent anyway. What you want is a long experienced antenna designer who can be permanently engaged on your behalf. There are very few of such creatures about. You will have to be numerically quite specific about particular problems. And even then you will get solutions which, with luck, are probably only in the right ball-park. On the other hand, ball-park solutions are perfectly satisfactory. In the nature of events, no-one has ever solved an antenna problem which is other than in a ball-park. Fortunately, antennas work quite well even when in the wrong ball-park. Download a free copy of EZNEC and in a few months time you may have solved your first complicated, specific problem. As time goes on, you will become more adept and there will be no need to engage a long experienced antenna designer. You will have become one youself and can offer your services for hire. If you have a specific problem you may, if you are lucky, find a computer program written by someone who has already solved it. But its highly unlikely to be exactly the same problem. It will be in a somewhat different ball-park. Optimisation is out! You will have to contend with whatever you can get your hands on. What's been done before. Take it or leave it! ---- Reg. |
Antenna optimization
JC wrote: 4/ Now let's suppose my objectives are max F/B as I have a QRM source opposed to my favourite transmitting direction and SWR 1.5 on a given frequency range as my transceiver is very SWR sensitive and I can't use an antenna tuner. I accept changing wire lengths and spacing but not boom length. Is there a way to have EZNEC, or another software, doing automatic iterations until it reaches the best F/B-SWR compromise ? K6STI's Yagi Optimizer 7.0 does a very nice job of this. You can choose the weighting of Gain, F/R, SWR or Impedance and optimize over any choice of frequencies. See my results for a pair of stacked KLM Yagis on 28 MHz he http://users.vnet.net/btippett/yagi_optimizer_7_0.htm Unfortunately K6STI no longer markets his software to hams (due to software piracy issues). Hopefully you can find someone with a copy who can optimize your initial results. 73, Bill W4ZV |
Antenna optimization
Unfortunately K6STI no longer markets his software to hams (due to
software piracy issues). Hopefully you can find someone with a copy who can optimize your initial results. 73, Bill W4ZV You could try ARRL's "YW", available with the "Antenna Book". Frank |
Antenna optimization
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Antenna optimization
"JC" wrote Thanks for help, I think I wrongly explained my problem, here is the question: 1/ I design an antenna, for instance a 3 el 20m beam. 2/ I enter into EZNEC wires dimensions, spacing, height, source..... 3/ EZNEC calculates gain, F/B, SWR....and results are acceptable. 4/ Now let's suppose my objectives are max F/B as I have a QRM source opposed to my favourite transmitting direction and SWR 1.5 on a given frequency range as my transceiver is very SWR sensitive and I can't use an antenna tuner. I accept changing wire lengths and spacing but not boom length. Is there a way to have EZNEC, or another software, doing automatic iterations until it reaches the best F/B-SWR compromise ? ---------------------------------------------------------------------- -------------- Let us see what would be involved if you had EZNEC and had to do everything else yourself the hard way. You already have a crude, satisfactory design for 3 elements, wire lengths, wire diameters, spacing, height, etc. Only the boom length and presumably wire diameters and height are fixed and you wish to optimise everything else for maximum F/B ratio and minimum SWR. Everything else comprises : 3 lengths and 1 spacing. This makes a total of 4 independent variables. You now vary the first variable over a range of say 4 increments, keeping all the other variables constant and keeping a record of the 4 results of F/B ratio and SWR You then vary the second variable over a range of 4 increments, keeping all the other variables constant and keeping a record of the results. You continue to do this until you have done all possible combinations of the 4 variables. You will have a 4-dimension array of results of F/B ratio and SWR, making a total of 512 observations. Now search the observations until you can find the maximum of F/B ratio combined with minimum of SWR If it looks as though the minimum SWR or the maximum F/B ratio lies outside the 4-dimensional array then shift the variables in an appropriate direction and repeat the whole procedure until a max and min are found. The trouble with modelling programs is you have to enter element lengths and spacing via the keyboard. It would be nice to have a program to do it for you. I am unfamiliar with the situation. Such a program might exist - one which outputs F/B ratio and SWR. ---- Reg. |
Antenna optimization
As mentioned in another posting, YO (Yagi Optimizer) would be a good
bet. Strange that piracy caused the author to quit offering it completely; seems like any sales are better than none, and not selling a program only makes piracy more likely, not less. But check out the EZNEC co-pilot program from Dan Maguire, AC6LA, at http://www.ac6la.com/. That page lists several of his offerings; it's MultiNEC that you'll be most interested in. Though it may not completely automate the optimization, it should make the process much easier and faster for you. Cheers, Tom JC wrote: Thanks for help, I think I wrongly explained my problem, here is the question: 1/ I design an antenna, for instance a 3 el 20m beam. 2/ I enter into EZNEC wires dimensions, spacing, height, source..... 3/ EZNEC calculates gain, F/B, SWR....and results are acceptable. 4/ Now let's suppose my objectives are max F/B as I have a QRM source opposed to my favourite transmitting direction and SWR 1.5 on a given frequency range as my transceiver is very SWR sensitive and I can't use an antenna tuner. I accept changing wire lengths and spacing but not boom length. Is there a way to have EZNEC, or another software, doing automatic iterations until it reaches the best F/B-SWR compromise ? JC - F8ND "Reg Edwards" a écrit dans le message de news: ... "JC" wrote in message ... Is there a software which can design an antenna (like EZNEC or similar ) then allows to automatically optimize its dimensions according to given requirements: max gain, F/B, min swr... and accepted dimensional parameters changes: boom length, spacing.... JC ---------------------------------------------------------------------- ------- Dear JC, You don't need software. What you describe is non-existent anyway. What you want is a long experienced antenna designer who can be permanently engaged on your behalf. There are very few of such creatures about. You will have to be numerically quite specific about particular problems. And even then you will get solutions which, with luck, are probably only in the right ball-park. On the other hand, ball-park solutions are perfectly satisfactory. In the nature of events, no-one has ever solved an antenna problem which is other than in a ball-park. Fortunately, antennas work quite well even when in the wrong ball-park. Download a free copy of EZNEC and in a few months time you may have solved your first complicated, specific problem. As time goes on, you will become more adept and there will be no need to engage a long experienced antenna designer. You will have become one youself and can offer your services for hire. If you have a specific problem you may, if you are lucky, find a computer program written by someone who has already solved it. But its highly unlikely to be exactly the same problem. It will be in a somewhat different ball-park. Optimisation is out! You will have to contend with whatever you can get your hands on. What's been done before. Take it or leave it! ---- Reg. |
Antenna optimization
As I just posted in another followup, MultiNEC (add-on for EZNec and
other NEC programs) takes care of just this sort of thing for you, and takes much of the tedium out of the process. As an Excel spreadsheet, it does require that you have Excel on the computer you're using. Cheers, Tom Reg Edwards wrote: "JC" wrote Thanks for help, I think I wrongly explained my problem, here is the question: 1/ I design an antenna, for instance a 3 el 20m beam. 2/ I enter into EZNEC wires dimensions, spacing, height, source..... 3/ EZNEC calculates gain, F/B, SWR....and results are acceptable. 4/ Now let's suppose my objectives are max F/B as I have a QRM source opposed to my favourite transmitting direction and SWR 1.5 on a given frequency range as my transceiver is very SWR sensitive and I can't use an antenna tuner. I accept changing wire lengths and spacing but not boom length. Is there a way to have EZNEC, or another software, doing automatic iterations until it reaches the best F/B-SWR compromise ? ---------------------------------------------------------------------- -------------- Let us see what would be involved if you had EZNEC and had to do everything else yourself the hard way. You already have a crude, satisfactory design for 3 elements, wire lengths, wire diameters, spacing, height, etc. Only the boom length and presumably wire diameters and height are fixed and you wish to optimise everything else for maximum F/B ratio and minimum SWR. Everything else comprises : 3 lengths and 1 spacing. This makes a total of 4 independent variables. You now vary the first variable over a range of say 4 increments, keeping all the other variables constant and keeping a record of the 4 results of F/B ratio and SWR You then vary the second variable over a range of 4 increments, keeping all the other variables constant and keeping a record of the results. You continue to do this until you have done all possible combinations of the 4 variables. You will have a 4-dimension array of results of F/B ratio and SWR, making a total of 512 observations. Now search the observations until you can find the maximum of F/B ratio combined with minimum of SWR If it looks as though the minimum SWR or the maximum F/B ratio lies outside the 4-dimensional array then shift the variables in an appropriate direction and repeat the whole procedure until a max and min are found. The trouble with modelling programs is you have to enter element lengths and spacing via the keyboard. It would be nice to have a program to do it for you. I am unfamiliar with the situation. Such a program might exist - one which outputs F/B ratio and SWR. ---- Reg. |
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