Thank you for posting this. I've watched your video a few times, and each time I understand more about the capabilities of the software. As an old guy, it's been a long time since I had to think in terms of the X,Y and Z axes! I'm sure to watch it again ... and again!
Velocity factor is mentioned a couple of times. That is not the reason that the length is not exactly half the wavelength. The real reason is "end effect", which makes the effective length of a half wave greater than the actual length. The degree of shortening increases with the diameter of the wire.
The average gain test adds up the gain in all directions and averages them all togather. The answer should be 1. If it's much off of one the model is flawed or at least reporting an inaccurate gain. It can be adjusted by adjusting the diameter of the segment that is excited / source. Simple antennas are usually ok but complicated models can get out of whack pretty easy. And you had a 65:1 frint to back but you ignored it and dropped the f/b without even looking at what the optimizer managed to do.
I hadn’t planned to do another. The idea behind this was to get people started so they could figure out the rest reading documentation. But it’s much harder to get started with just the written documentation usually.
Being a numerical (as opposed to analytical) model, it calculates each segment individually and adds them together. So with more segments the answer should be more precise, which will be a tradeoff against the time it takes to calculate. There is a limit to the number of segments in a model (can be changed by recompiling I think) and also some constraints to do with segment size, like a minimum ratio of the segment length to its diameter. For connected wires, the segments in the wires must be similar in size as well. The size/compute time tradeoff was more important when the program was written long ago as computers were a lot slower and something that takes seconds today would take hours or days back then. I was playing with a dipole model on the computer I assembled a few months ago and with around 400 segments it takes about a second to run.
This is one of, if not the best 4NEC2 tutorial on RUclips. Thanks a ton for putting it together. I learned a lot that I never saw in other videos.
covers a wider range of features. Well done
Thank you for posting this. I've watched your video a few times, and each time I understand more about the capabilities of the software. As an old guy, it's been a long time since I had to think in terms of the X,Y and Z axes! I'm sure to watch it again ... and again!
Dope tutorial mate! Helped out a lot with my finals assessment in uni
Velocity factor is mentioned a couple of times. That is not the reason that the length is not exactly half the wavelength. The real reason is "end effect", which makes the effective length of a half wave greater than the actual length. The degree of shortening increases with the diameter of the wire.
Great tutorial. Now I have some basics to jumpstart my experiments. Thanks
Excellent tutorial, many thanks
Thank you for this. You may have only had a few viewers in the live stream but it looks like this video is up to nearly 8K views as of today!
Brand new to this software.Thank you for your efforts.This will help me to learn.
Thank you for your very nice presentation.
Thanks for the tutorial.
The average gain test adds up the gain in all directions and averages them all togather.
The answer should be 1.
If it's much off of one the model is flawed or at least reporting an inaccurate gain.
It can be adjusted by adjusting the diameter of the segment that is excited / source.
Simple antennas are usually ok but complicated models can get out of whack pretty easy.
And you had a 65:1 frint to back but you ignored it and dropped the f/b without even looking at what the optimizer managed to do.
Hi
Thank you so much. I used this to get myself started. Watched it offline mid-May
W6MHX
great tutorial man, you save me, i have to do a simulation for a proyect and i don't know how 4NEC2 works
Thanks, good use of my time to get me up to speed on this.
Great guide!
gracias brother
thanks
Nice video
Good night friend, can this program work with negative rods? underground?
It doesn’t simulate underground, only contact with the ground plane. As for negative I’m not sure. I’m really very amateur at this EM/RF engineering.
is there going to be a second part with more details?
I hadn’t planned to do another. The idea behind this was to get people started so they could figure out the rest reading documentation. But it’s much harder to get started with just the written documentation usually.
this may be a stupid question but what are the segments. Are they just used to determine where the source will be inputted.
Being a numerical (as opposed to analytical) model, it calculates each segment individually and adds them together. So with more segments the answer should be more precise, which will be a tradeoff against the time it takes to calculate. There is a limit to the number of segments in a model (can be changed by recompiling I think) and also some constraints to do with segment size, like a minimum ratio of the segment length to its diameter. For connected wires, the segments in the wires must be similar in size as well. The size/compute time tradeoff was more important when the program was written long ago as computers were a lot slower and something that takes seconds today would take hours or days back then. I was playing with a dipole model on the computer I assembled a few months ago and with around 400 segments it takes about a second to run.