How to Model Antennas with 4NEC2 Antenna Modelling software - Part 1, the basics

[@wa2ooo15]

WA2OOO here. I have known Justin for quite some time, bought many of his antenna & designs and modified quite a few others to my own needs. Everything Justin makes and sells is a top notch and the highest quality antenna design you can buy Period. Most common commercial antennas sold today were designed 50 years ago. Justin built his company on performance. And he has a passion for it. And the performace is second to none.

[@hamradioguy-g0ksc96]

Thanks for the 'flowers' !

[@josegerardoquejada1745]

Justin (6:10) - "When there is any form of matching or transformation, there is going to be loss. There is no method of transforming or matching anything known to science that is 100% efficient. If you can get rid of that matching device..." I totally agree with this! That is why you are designing an antenna in the first place... so it can be 50 ohms. PERIOD. Thanks, Justin, for creating this channel. I have been following your website, and made several of your HF designs. Keep up the good work! Thank you for sharing the science and techniques! 73s, Gerry (DU7EYG)

[@hamradioguy-g0ksc96]

Thank you. So many things like matching devices are accepted as normal but it is just not the case! How many antennas with no matching devices have power input limits? Makes you think doesn’t it?

[@ihavecojones]

Actually not having matched impedances in transmission systems willdo 2 things: 1. You will lose transmission power... Alot of transmission power. 2. Have a bad enough SWR and you will burn your radio's output. 3. Good luck building a naturally resonant antenna and transmission line at anything above 10 meters. You need the right antenna lenght and design, the right rransmission line lenght, the right geometry, the right grounding... And anything bellow 1GHz is going to have such small tolerances that it's going to be practically impossible to achieve perfect tuning...even a small wire whisker is going to detune your system. Also there's ground interference, building interference even the mast will interfere with your system. This is basic 3rd year analog electronics stuff.

[@bradgillis1426]

Just ran across your Tutorial and where I've always wanted to learn 4Nec2 decided it'd be a great experience to learn from you. Having a bit of trouble getting my 2 meter 5 el lfa yagi to tune in the FM portion of the band so thought I might get a heads up with the software to make fixing it easier. Also sent a link to a friend who is building a similar antenna of your design as he is also getting into antenna design software.

[@hamradioguy-g0ksc96]

Let me know exactly what your issue is, I will help

[@christophermkiremamaghanga9148]

thanks for the tutorial

[@hamradioguy-g0ksc96]

Any time

[@wmanojnishshankadias162]

Thank you very much for video

[@hamradioguy-g0ksc96]

You are welcome, thanks

[@istvanszabo3275]

Hi Guy! With which software can I simulate the effects of my (grounded) balcony rails on my delta loop antenna? I mean construct a complex ground structure(the rails). My bottom, horizomtal side of the delta is behind the rails, metal 1m spacing, lamda is 10m. Thank you! 73

[@stanholmes4293]

Thank you Justin for publishing the 4nec2 series of video's. I found them extremely helpful. Can you answer my question pleas: I'm using the TYPE Helx to create a helical coil. I want to add a straight wire on top of the coil. How do I find the end point of the coil xyx co-ordinates to add the straight wire? Regards Stan

[@devinsword5777]

i came here wondering how to design and model my own antenna using 4nec2. im leaving here wondering how to design and model my own antenna with 4nec2, but now i know i can load someone else's design into the program, if i ever wanted to do that for some reason

[@43WR155]

Hi Justin, @ 5.25. Would like to use NEC4-5 with 4NEC2. Any chance of a follow on vid on how to set up NEC4 or 5. What's your thoughts on NEC5 ?

[@TheZaxanoid]

How does NEC5 compare to NEC4? For some reason NEC4 is (Non-U.S. Academic/Noncommercial) $500 but for NEC5 there is an Individual license @ $110. They do say "NEC-4 may remain the preferable code for modeling antennas such as Yagis where accurate resonant frequenciesare critical." For a Ham, $110 is obviously more palatable!

[@hamradioguy-g0ksc96]

If you look at the changes in NEC5 there are not any to impact conventions 'wires only' Yagis. Additionally, for Yagis from HF to and through VHF, accuracy with NEC4 is exceptional, you will see many reports from builders that have built antennas from my designs where they have said 'no adjustments required at all.

[@plyrvt]

1) from the point of view of HAM. For SW/LW antennas you need Sommerfeld ground model, so zero benefits from other-than-4NEC2/MMANA engines. for VHF/microwave antennas there is zero benefit from higher impedances/reactances accuracy., because all these engines cannot model non-balun-type antennas, and balun design (which can not be modeled in this engines anyway) has 100x adjustments bigger than error of engines in terms of impedance matching/error/transformation. 2) from point of view antenna developer RF engineer, all these MoM engines are total crap and waste of time.

[@robrees8685]

@@hamradioguy-g0ksc96 I get that NEC4 is fine. I meant, is NEC5 also ok - or not? I can afford NEC5 at $110, but not justify $500 for NEC4

[@ahbushnell1]

I have modeled yagi and a quad antenna over a ground plane. I see the pattern breaks up from what I guess are interference fringes. I was wondering in the real world they would be that distinct. The ground is not uniform and sharp like the model.

[@ihavecojones]

You lost me at "there is no need to have any matching" and "there is going to be loss". Sorry, but basic, 3rd year Analog Electronics theory is completely against your stance. Good luck making a 160m transmitting line-antenna system. Even transmission line lenght affects a system's impedance.

[@bruceblosser384]

When the Reflector is moved further away from the driven element, the SWR goes up, but the gain also goes up... So then am I actually getting any more real gain, if I have to use a Gamma match, to get the SWR back down? :)

[@bruceblosser384]

I don't see anywhere that I can download this particular antenna file?