I appreciate drawing all of the design on the whiteboard. Too often I just dive into putting numbers into the matrix and get wrapped around the axle and needing to rework everything becoming a mess. Good to have it all figured out before you hit the keyboard.
Yes, it is good to have it all figured out before you hit the keyboard. That is why I emphasize in all my videos to plan before you jump. Know what you are going to do before you try to do it. It saves us so much frustration and tons of time. 🙂
I just stumbled upon your channel. Thank you for your explanation of traps and trapped dipoles. This has been a big help. I have used 4NEC2 for several years but never ventured into the realm of designing traps. This will help me proceed and I may even be prompted to pull down the Delta Loop in favor of a trapped dipole for 40-80. WA7DJS
I have EZNEC, but it looks like 4NEC2 has some good features, so I will download it as well. I have been trying to develop a tiny horizontal 80m antenna (total space available is 8m) with reasonable efficiency. As I suggested in the comments on the last video, it might be better to put the traps somewhere like 6.9 MHz instead of 7.15 in order to avoid the very high voltage that appears across the trap at resonance.
Yeah, 7.15 was just a "pick a number out of the air" kinda place, not the final choice if I were to actually build one of these. I am working on a 20/40m portable inverted vee for field-day operations. Its traps are tuned to 14 MHz. The one thing that keeps me coming back to 4NEC2 after trying others is the ability to define Symbols. These are fantastic to keep thing organized and help a LOT when experimenting. These go along with the Optimizer as the Optimizer adjusts the value of the defined symbols to achieve your goals. On your suggestion, I added it to the text in the desciption of the last video.
Dear Mr. Gable, I am hoping that you can enlighten me? I would like to ask you if it is feasible to add traps to an OCFD antenna? Also if the OCFD can be used as a Verical and for the VHF/UHF bands? I hope to create a 2m-1.25m-70cm tri-band in the OCFD configuration. Thank you kindly for sharing you vast experience and knowledge. You are somehow able to present a complicated subject in a bite by bite way that is easy to digest. Hmm, I must be hungry 😂
LOL!😁 I have never actually done anything like that. With that said...I would imagine you could do all of that. If I were you, I would do a virtual experiment using the FREE 4NEC2 antenna modeling program before you build. If you are unfamiliar with it, I *do* have some videos on the subject. Check out my 4NEC2 playlist. 🙂
Thank you for this I have wanted to do this for a long time. However the inductactance calculation was the area that I need help to understand can you elaborate how you worked out the math.
I'm assuming you are referring to the whole business of how to know how many turns and so on to get the desired inductance. There is a formula which can be somewhat intimidating, but not actually that difficult. I got tired of working through it, so I created a spreadsheet to do the heavy lifting for me (and avoid the math mistakes). Here is a link to it (it is a ZIP file which contains an Excel spreadsheet): drive.google.com/file/d/1AdrSdGbnhZ1KCxvJLqcYDStge7csgBzV/view?usp=drive_link You enter the stuff in yellow. It calculates the stuff in "tan". Hope this helps. 🤠
Never used a modeling program, but WOW! Complicated for the only Semi-Geek in me. I wonder if I can model a 20-40-80 EFHW/NVIS. Rather than let nature pick my resonate best SWRs use Traps to force the low SWRs where I want them? I think I understand the low SWRs won't be any lower but I may be able to shilf then around a little. For either Phone areas or Digital areas of the bands. Thoughts? I'm in ARES, SkyWarn and am most interested in mobile and reliable comms with local groups. No interest in DX. Thanks so much. K0WOZ
Yes, you can, indeed, model all of that using 4NEC2. Check out the tutorial videos that I have on the program to help you get a handle on it. The biggest obstacle is getting our head wrapped around how they think about the model. Once we can understand the concept of a wire with segments and that we drop into this wire a source and traps, we are most of the way there. Just a not, too, wires can ONLY be connected at their ends. My second biggest obstacle is when it throws an error. It doesn’t spell out what the issue is in nice, easy to understand language. It is all in a very abbreviated nomenclature which takes a bit to unravel what it means. The best was to get past all of this is just to play, play, play with it. I encourage you to just dive in with simple stuff and slowly add things, learning as you go. It is great fun and very satisfying (for me). It is amazing how close the simulation is to real life, too.
I find your teaching better than the all others. Is it possible to design a Patch antenna with ANEC2? if so show me how we can make such an antenna Patch as you did for a simple dipole.
Thank you for the encouragement! I am totally unfamiliar with ANEC2. I would imagine that it requires very similar inputs. I have a video on the Basics of 4NEC2 (ruclips.net/video/Zd6BT558YRA/видео.html) and one on modeling a simple dipole (ruclips.net/video/A6IiGWOI9KU/видео.html). Maybe these would help?
@@eie_for_you I'm sorry it's not ANEC4 but 4NEC2. Is it possible with 4NEC2 to model or simulate an 8 elements Patch antenna? The two videos you sent me the links are wonderful. A very good professional explanation. Congratulations
Hmmmm, I have never designed a patch antenna. However, you might find something to help if you look in the "...4nec2\models\SPatch" folder in the install directory for 4NEC2. Wish I could be more help.
So the lengths entered into the Geometry for wires is in segment units and the Height is in feet. Is this not a problem? Or does the scaling difference simply fall out as a constant once the analysis is run? Why not run everything as segments, including H? Or run everything as feet? What am I missing?
Let me see if I can help you see what I am doing ..... I establish a given segment length as the first line on the "Symbols" tab. All of the lengths entered in the geometry are entered and calculated in feet. The number of segments for each length is calculated and will vary with the length of the wire. I do this so that I can make sure the segment lengths for each of the wires remains reasonably close to one another. If the segment length of one wire is too far afield of the segment length for another wire, you get an error. So, to avoid this error and to allow me to adjust segment lengths (to keep 4NEC2 happy) globally by changing the value of one symbol, I define the design-wide segment length. ==> 008g-GENERIC trapped_dipole&inv-vee, 2022-05-01.nec So, looking at the above NEC file using Notepad++ (this computer doesn't have 4NEC2 installed), I see that I set L1 = ~34ft (inner wire) and L2 = ~21ft (outer wire). I then calculate the number of segments for each wire based on the length in feet and the established segment length (Seg_len). --> L1_segs & L2_segs Then I calculate the coordinates for the anchor points for the inner and outer wires using the length of each wire, the angle between the vertical and the leg and some trigonometry. --> L1_X, L1_Z, L2_X, & L2_Z The Y coordinates all = 0 All of this is on the "Symbols" tab. Then we go to the "Geometry" tab to see these calculated values being used to define the antenna. Hopefully I've been able to unravel this a bit for you.
Thank you for the fast reply and generosity with your time. Don't know how I was seeing it but I thought you were calculating L1_X and others as increments of segments and entering those as lengths for x and z. Sorry, guess I was seeing all the trees and not the forest.
You have to open the 4NEC2 program first, then load the file of interest. The one labeled "GENERIC" is the general one for everyone's experimentation. The other files are my various versions of the generic file for various given configurations. If you do not have the 4NEC2 program installed, the link to the download site should be in the description for the video. Hope this helps. 🙂
I appreciate drawing all of the design on the whiteboard. Too often I just dive into putting numbers into the matrix and get wrapped around the axle and needing to rework everything becoming a mess.
Good to have it all figured out before you hit the keyboard.
Yes, it is good to have it all figured out before you hit the keyboard. That is why I emphasize in all my videos to plan before you jump. Know what you are going to do before you try to do it. It saves us so much frustration and tons of time. 🙂
I just stumbled upon your channel. Thank you for your explanation of traps and trapped dipoles. This has been a big help. I have used 4NEC2 for several years but never ventured into the realm of designing traps. This will help me proceed and I may even be prompted to pull down the Delta Loop in favor of a trapped dipole for 40-80. WA7DJS
WOW! Glad it helped!
I have EZNEC, but it looks like 4NEC2 has some good features, so I will download it as well. I have been trying to develop a tiny horizontal 80m antenna (total space available is 8m) with reasonable efficiency.
As I suggested in the comments on the last video, it might be better to put the traps somewhere like 6.9 MHz instead of 7.15 in order to avoid the very high voltage that appears across the trap at resonance.
Yeah, 7.15 was just a "pick a number out of the air" kinda place, not the final choice if I were to actually build one of these. I am working on a 20/40m portable inverted vee for field-day operations. Its traps are tuned to 14 MHz.
The one thing that keeps me coming back to 4NEC2 after trying others is the ability to define Symbols. These are fantastic to keep thing organized and help a LOT when experimenting. These go along with the Optimizer as the Optimizer adjusts the value of the defined symbols to achieve your goals.
On your suggestion, I added it to the text in the desciption of the last video.
Dear Mr. Gable,
I am hoping that you can enlighten me?
I would like to ask you if it is feasible to add traps to an OCFD antenna?
Also if the OCFD can be used as a Verical and for the VHF/UHF bands?
I hope to create a 2m-1.25m-70cm tri-band in the OCFD configuration.
Thank you kindly for sharing you vast experience and knowledge.
You are somehow able to present a complicated subject in a bite by bite way that is easy to digest.
Hmm, I must be hungry 😂
LOL!😁
I have never actually done anything like that. With that said...I would imagine you could do all of that.
If I were you, I would do a virtual experiment using the FREE 4NEC2 antenna modeling program before you build.
If you are unfamiliar with it, I *do* have some videos on the subject. Check out my 4NEC2 playlist. 🙂
Thank you for this I have wanted to do this for a long time. However the inductactance calculation was the area that I need help to understand can you elaborate how you worked out the math.
I'm assuming you are referring to the whole business of how to know how many turns and so on to get the desired inductance. There is a formula which can be somewhat intimidating, but not actually that difficult. I got tired of working through it, so I created a spreadsheet to do the heavy lifting for me (and avoid the math mistakes).
Here is a link to it (it is a ZIP file which contains an Excel spreadsheet): drive.google.com/file/d/1AdrSdGbnhZ1KCxvJLqcYDStge7csgBzV/view?usp=drive_link
You enter the stuff in yellow. It calculates the stuff in "tan".
Hope this helps. 🤠
Never used a modeling program, but WOW! Complicated for the only Semi-Geek in me. I wonder if I can model a 20-40-80 EFHW/NVIS. Rather than let nature pick my resonate best SWRs use Traps to force the low SWRs where I want them? I think I understand the low SWRs won't be any lower but I may be able to shilf then around a little. For either Phone areas or Digital areas of the bands. Thoughts? I'm in ARES, SkyWarn and am most interested in mobile and reliable comms with local groups. No interest in DX. Thanks so much. K0WOZ
Yes, you can, indeed, model all of that using 4NEC2. Check out the tutorial videos that I have on the program to help you get a handle on it. The biggest obstacle is getting our head wrapped around how they think about the model. Once we can understand the concept of a wire with segments and that we drop into this wire a source and traps, we are most of the way there. Just a not, too, wires can ONLY be connected at their ends. My second biggest obstacle is when it throws an error. It doesn’t spell out what the issue is in nice, easy to understand language. It is all in a very abbreviated nomenclature which takes a bit to unravel what it means. The best was to get past all of this is just to play, play, play with it. I encourage you to just dive in with simple stuff and slowly add things, learning as you go. It is great fun and very satisfying (for me). It is amazing how close the simulation is to real life, too.
I find your teaching better than the all others.
Is it possible to design a Patch antenna with ANEC2? if so show me how we can make such an antenna Patch as you did for a simple dipole.
Thank you for the encouragement!
I am totally unfamiliar with ANEC2. I would imagine that it requires very similar inputs. I have a video on the Basics of 4NEC2 (ruclips.net/video/Zd6BT558YRA/видео.html) and one on modeling a simple dipole (ruclips.net/video/A6IiGWOI9KU/видео.html). Maybe these would help?
@@eie_for_you
I'm sorry it's not ANEC4 but 4NEC2. Is it possible with 4NEC2 to model or simulate an 8 elements Patch antenna?
The two videos you sent me the links are wonderful. A very good professional explanation. Congratulations
Hmmmm, I have never designed a patch antenna. However, you might find something to help if you look in the "...4nec2\models\SPatch" folder in the install directory for 4NEC2. Wish I could be more help.
Thank you very much.
You are very welcome! 🙂
So the lengths entered into the Geometry for wires is in segment units and the Height is in feet. Is this not a problem? Or does the scaling difference simply fall out as a constant once the analysis is run? Why not run everything as segments, including H? Or run everything as feet? What am I missing?
Let me see if I can help you see what I am doing .....
I establish a given segment length as the first line on the "Symbols" tab.
All of the lengths entered in the geometry are entered and calculated in feet.
The number of segments for each length is calculated and will vary with the length of the wire. I do this so that I can make sure the segment lengths for each of the wires remains reasonably close to one another. If the segment length of one wire is too far afield of the segment length for another wire, you get an error. So, to avoid this error and to allow me to adjust segment lengths (to keep 4NEC2 happy) globally by changing the value of one symbol, I define the design-wide segment length.
==> 008g-GENERIC trapped_dipole&inv-vee, 2022-05-01.nec
So, looking at the above NEC file using Notepad++ (this computer doesn't have 4NEC2 installed), I see that I set
L1 = ~34ft (inner wire) and
L2 = ~21ft (outer wire).
I then calculate the number of segments for each wire based on the length in feet and the established segment length (Seg_len).
--> L1_segs & L2_segs
Then I calculate the coordinates for the anchor points for the inner and outer wires using the length of each wire, the angle between the vertical and the leg and some trigonometry.
--> L1_X, L1_Z, L2_X, & L2_Z The Y coordinates all = 0
All of this is on the "Symbols" tab.
Then we go to the "Geometry" tab to see these calculated values being used to define the antenna.
Hopefully I've been able to unravel this a bit for you.
Thank you for the fast reply and generosity with your time. Don't know how I was seeing it but I thought you were calculating L1_X and others as increments of segments and entering those as lengths for x and z. Sorry, guess I was seeing all the trees and not the forest.
@@GreenGuyDIY Well ... we've all done it! So welcome to the club "human"! 🙂
I am *very* glad I was able to help.
I downloaded the 6 4NEC2 files & when I click on them, nothing happens. Also, why are there 6 files? Are they just 6 examples of the same program?
I am using Win 10.
You have to open the 4NEC2 program first, then load the file of interest. The one labeled "GENERIC" is the general one for everyone's experimentation. The other files are my various versions of the generic file for various given configurations.
If you do not have the 4NEC2 program installed, the link to the download site should be in the description for the video.
Hope this helps. 🙂