EFHW Antenna Simulation Using MMANA GAL
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- เผยแพร่เมื่อ 30 ก.ค. 2024
- This is a simulation of the radiation pattern of an End Fed Halfwave antenna (EFHW) using the program MMANA GAL. The EFHW uses a 49:1 transformer so the SWR is set to 2450 ohms for the simulation.
0:00 - Intro
0:40 - 15m Simulation
06:40 - SWR 2450
09:10 - Optimization
14:50 - Far Field plots
16:18 - 3D rendering
19:50 - Other frequencies - วิทยาศาสตร์และเทคโนโลยี
This is the most straight forward and comprehensive MMANA GAL tutorial i've ever watched. And I watched quite some tutorials.
Thank you!
What you said + Me
I'm a Japanese amateur radio operator.
This video was very helpful.
I understand that a technique is required to analyze EFHW with MMANA.
I would also like to introduce this video to amateur radio operators in Japan. thank you!
Thank you for the great video. Using a 66 ft N9SAB efhw antenna on 20m I lowered my antenna mast (painters pole) to 19ft to get as close a possible to get a 5 degree take off angle to maximize my antenna gain takeoff. It has helped significantly.
Thank you for the comment. Yes, I heard of the 5-8 degree elevation rule of thumb from Callum McCormick, the DX Commander, and it made sense. He also models his antenas in MMANA-GAL. Best of luck & 73!
Many thanks for running through the basics. This video has really helped me.
Thanks for the comment and glad it was helpful. Best of luck with all your projects & 73!
Very good! I usually work within the microwave bands, but this software and your knowledge is outstanding. Clearly presented and appreciated!
Thank you for the comment. I believe that MMANA GAL software has a straightforward learning curve and gives good results. Best of luck in your work & 73!
Super helpful! Thanks.
Thank you for the comment and best of luck in your projects!
Thank you very much, very informative, will be big help. Thanks.
Thank you for your comment and all the best in your work! 73.
Great information, thanks
Thank you for the comment. 73!
How to model a 20m-6m hexbeam?
Thank you for the comment. Unfortunately I've not modeled that antenna; however, I believe that you'd go into Edit>Wire Edit>XY, XZ, and YZ in MMANA GAL and draw out the segments. Best of luck with your project & 73.
SWR is important but shouldn’t you also try to get jX closer to zero?
Thank you for the comment. Yes, absolutely. Per my understanding, the SWR is defined in terms of load impedance (ZL) minus the line's charactersitic impedance (Zo) in such a way that: If ZL is very close to Zo which in our case is typically 50ohms, then SWR goes to 1.0. This is normally expressed as 1.0:1.0 or 1:1. So in my understanding of this, the more ZL approaches R=50 and jX=0.0, the more our SWR is closer to the perfectly matched transmission line value of SWR= 1.0.
Now, the reactive (jX) part of ZL gives an indication of whether the load is too inductive (+) or too capacitive (-), so then we as Hams know whether to add inductance or capaticance to our system in order to null out the jX and get to the centerpoint of the Smith chart which is 50 ohms, and zero jX. Recall that we want ZL to be at ZL = 50 +j(0) or as close to it as practically possible for our antenna.
Lastly, note that the Smith chart's centerpoint is actually 1 since it normalizes the R values to 50 ohms for Ham transmission lines, though for TV lines they use 75 ohms I believe. This way they don't have to make different Smith charts depending if your transmission line's charactersitic impedance is 50 ohms or 75 ohms, or any other value.
Best of luck with your project & 73!
We’ll done!
@@wildbill1 Thank you for the comment & 73!
Isn't the counterpoise on the 50ohm primary side of the 49:1 unun transformer while the antenna is on the 2450ohm secondary side? How does MMANA compensate for this impedance transformation of the counterpoise? And how do you compensate for the primary parallel 110pf capacitor in your model? Have you built, tested, and measured the actual length's of the antenna against the simulation?
Thanks for the toughtful comment. The way I look at it, the coax sheath is my counterpoise in the simulation. MMANA GAL doesn't consider an impedance transformation for the counterpoise, it does an impedance transformation from the feedpoint to the antenna element. The counterpoise is the ground wire, coax sheath really, connecting the ground on the transformer to my floating ground of my transceiver. I could probably fiddle more with the counterpoise in this model but I found that this simulation gave the insight that I needed to build the EFHW antenna and start testing it.
I didn't model the capacitor as a load in my simulation. However, to your point, I have seen reports that the high frequencies are helped by using the capacitor but my model doesn't include this effect.
Yes, I have built, tested, and folded (not cut) my antenna element to resonate on 40m, 20m, 15m. The EFHW antenna I built last year at field day is pretty much what I modeled here and it's the one that I take on POTA outings now a days. It's very portable and you can drape it over a tree branch, or use a fiberglass pole to hold up the antenna element end. This makes for a quick setup.
Hope that answers the doubts. 73!
great, thanks a lot, very helpful!
Thanks for the comment. Best of luck in your project & 73!
i have made a T2LT to compare it with my endfed, now i dont know how to model it in mmana. any advice? what antenna form is it? @@quantumradio
@@jomckarth4836 Unfortunately I am not sure about how to model the Tuned Transmission Line Trap antenna. A load consisting of an inductive coil plus a capactior element in addition to a wire segment might be the way to go. Best of luck & 73.