Why I don't trust computer designed antennas
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- Опубліковано 11 лип 2024
- In this video, I show you how I am designing a Quagi antenna (BiQuad/Yagi combination) and why I don't build the computer generated models. This is for long range FPV and long range WiFi use. I should be able to get a WiFi signal from 5-6 miles away and as far as FPV... this is a 65 mile video link... maybe more.
I fully admit that I could get this closer by adding in a few more variables to my program, but not amount of programming will replace real-world testing. I go through this with all of my antenna designs to verify that when the end user puts a VAS antenna on their equipment, their signal is the best it can possibly be. - Наука та технологія
Alex, you and Hugo make the best antennas! Keep up the good work!
This is brilliant. Good amount of information without being overwhelming and solid presentation. Thank you.
This was cool to see how you build and work an antenna design through to optimization. The foam "trick" was brilliant. Thank you.
Frank Barajas just a heads up, if you haven’t gotten the profile picture with permission, the copyright wannabe cops will report you... not me... I could care less honestly.
Beezy King - Thanks. I am working on changing it. So no worries.
Love your videos about antennas, thank you
Great vid Alex still love your antennas can't wait to try the diamond just came in ;)
Great explanation love your videos
You are a magician, keep on doing that voodoo that you do and we can go further. Thanks man! 👍
Like #101, love your antennas Alex.
Thank you ibcrazy VAS all the way
Thanks for all of the amazing information bro
Great demonstration on the spacing and how it affects the overall gain and vswr. I’m able to use the Agilent 9918 model at work to test and check the antennas prior to using them on a flight, just haven’t seen how to go into the voltmeter mode on the reception aspect. If there was one item of test equipment I could attain, it would be the Fieldfox if the price tag wasn’t too far off from that of a new car...
I have been messing with biquad yagi antennas for a while for wifi. Cant wait for you to finish this and go into production so I can stop messing around and get one
Very interesting info!
I only fly your antennas. They are by far the best!
Alex, you are awesome! I just gotta say I really appreciate your work and dedication man. You and Hugo are the best thing to happen to fpv. And I know your work goes far beyond our little hobby, you actually contribute to the advancement of rf technology in real world applications. I want to offer a genuine thank you for your work, attention to detail, and determination. Thanks brother!
I haven't been able to enhance the rest of the World as much as I would like to... which is actually the point of this design. People in rural areas often cannot get internet connectivity. I am researching ways to hit 3G and 4G towers at very long range so they they might be able to access the internet.
The owner gets to play while minions work. Keep up the great work Alex📡
They put up with a lot of my crap, too. Those guys are some of the best employees a guy could ask. They are just as interested in making the best product possible as I am.
Thank you
U gave been nominated as a honarary member of the yawlumni
5:42 - True, you would want to allow for the feed, in a small antenna it has a greater effect. Also keep the measuring antenna out of the near field.
LowLightVideos - When I first made this antenna, I had the block rotated the other way and the measuring antenna was in the near-field. That’s why I rotated the block for this video. Much more accurate.
Awesome :)
Hey Alex, great job on the antenna! I previously posted a simple doubt I had, will be very happy if you can clarify me on it. My question is about the immortal t antenna - I've seen many people classify it as a dipole antenna, and I'm not sure about that. If it has a ground on the opposite side to the active wire, instead of an active part as I've always seen dipoles to be in, how can it be classified as a dipole? Shouldn't it be a monopole with a ground reflector?
I'll be very happy if you can kindly help me clarify this. I'm sorry for any time or inconvenience I caused you on this.😊
P.s. You've inspired me a lot to take up and study about antennas. I'm entirely grateful for that.
The immortal T is in fact a dipole. It is the way it is described which causes confusion. There are actually 2 active elements: the driven, and the reflected element (often called the counter element or counter-poise). The reflected element is connected to the shield (ground) and while it might not sound like that should be resonant, it in fact is an active part of the antenna. Without getting too far into detail, a sinusoidal wave may stand on any wire of proper length and size regardless of its connection points, hence closed and open loop antenna designs. This phenomenon, while useful for antennas, causes some serious issues in designs of transmitters and high frequency devices.
RF signals are truly an amazing phenomenon. If you ever need resources, I suggest the ARRL. They have some excellent reading on the topic.
I can’t decide between the VAS 433 diamond or the 2.4 helical so I just installed both rx. Life’s ruff.
What is the best goggle antenna to use for quad freestyle? I'm using the Rapid Fire.
Great job!! One wonder how much is that nice network antenna analyzer that you have there?
THis particular model is $17,000. The other unit I have is $24,000. It is indeed much cheaper to buy software... but not nearly as accurate.
@@CAGreve1231 Thank you very much sir!
the central boom of any yagi antenna of whatever mhz should not use metal boom, am I right?
yxhankun - You can, but it changes the element spacing some.
Would it be possible to make a high gain antenna array with a signal pattern like a hi-hat? Kind of like an omni but with a really high gain around the waist of the torus. Would be great for static receivers.
Fraser Steen - the “Franklin” antenna is just this type. Check it out. Lots of tutorials out there on it, too!
@@CAGreve1231 amazing, thanks!
Wouldn't you need a anechoic chnber to simulate true free air? How much does that play a role on computer vs real world?
For perfection, maybe. I find this method is quite accurate. I have other tools I use to obtain the full radiation pattern. The issue is that different humidity will change the results due to the change in propagation speed. Thus, I keep my shop around 60% humidity for tests like this.
Ok... got a question at 3:40 there...
The two antennas are fairly close together... a meter maybe. You seem to push elements of the sending antenna closer to the measuring point. Wouldn't this increase signal strength by itself? Especially with those short distances it seems like this isn't the right method to measure the signal strength changes if you don't bring the sending antenna's base back to then have the same air gap as before
DerClaudius - The distance is just outside of the Quagi near field pattern. The reason to keep it relatively close is to reduce measurement errors due to multipathing. The separation is a balance between staying out of the near-field and not incurring multipath errors. I agree that more testing at a longer distance should be performed.
@@CAGreve1231 Thank you very much for the explanation, this stuff goes over my head. If you don't mind, I'm having another question.
My understanding is that the wavelength is around 5cm, so points of constructive/destructive interference would also alternate around those distances if you have multipath problems. As all the walls are pretty close, the reflection also come from pretty close, so there is probably interference. Wouldn't this change the measurement if you just move the the measurement point around a bit around that magnitude of 5cm? Or is there something that compensates for these local fluctuations of signal strength?
Anyway, if the errors due to the closeness of the antenna's size to the actual air gap get fairly high, you probably don't want to be that close together for optimizing, because the error might not be just a percentage that gets applied to all antenna shapes, but you may actually optimize for the wrong thing (long antennas that minimize air gap) and actually pick a shape that'd actually be worse if you'd add just 3m to the distance.
@@DerClaudius - In my testing the walls and floor are definitely an issue on measurements. In this case you can see some fluctuation in my readings due to that exact issue. However, with the area given, those errors are surprisingly small given that multipathing is significantly weaker because it falls off with beam angle as well as the fact that I am measuring with a high F/B antenna. THus, the key is using a helical as a measuring antenna to help mitigate the issue.
@@DerClaudius - This is 2.4GHz, so the wavelength is closer to 5" (12.5cm). Reflections come with attenuation due to distances as well as signal absorption. Thus, the multipathing issue is quite minimal. The way this works is to amplify the reflections between the elements. Thus, the distances between the elements are roughly the same with small adjustments for other factors within the structure.
How do you discombobulate the congruant bifactor of the resulting arch type infused surfactant tho?
jackosmeister - I bought a special edition Turbo Encabulator.
@@CAGreve1231 Ahhh, so you're running a prefamulated amulator in a unilateral phase detractor to two spurving bearings?
@@jackosmeister - The phase detractor is the ONLY way to go. Bearings wear. detractos don't ;)
Where I read 433 and 1.2 is best combination? isn't it?
uap -Best is always subjective. What is best for me may not be what is best for you.
You don't pick up any stray capacitance from the foam? Stray capacitance would bring your optimal VSWR & spacings to a lower frequency than the design/model. Your measured resonant frequency was lower than your target frequency...
Bill G. Very little, actually. This is the lightest EPS foam they make. However, you are indeed correct that it defines it a little bit. The humidity in the air causes much more trouble than the foam.
How do you now the radiation patern when experimenten with the antenna?
Erwin L - I spend a lot of time measuring from different angles. I use a string to hold proper distance on all measurements and basically make a giant protractor. I do the measurements outside for best accuracy.
@@CAGreve1231 keep up the good work :-)
How about a link to your product?
This won't be out for several months. It is imply some prototyping I was doing. I was really shocked at how bad my computer models were on this one. They are usually much closer, but still not exact.
Wow amazing , I want to learn from you how to make my diy pepper box extreme for my personal use only , pls teach me my idol. I will wait for your reply thank you .
jill julaton - The Xtreme is a challenge and without a vector analyzer it is nearly impossible to make correctly. That stated, if you Email me, I can send you some tunes parts to make your own.
Thank you my idol sorry I don't know your email , my email is jilljulaton4@gmail.com sorry I made a mistake , I want to learn and make my diy crosshair Xtreme antenna for my personal use only because the signal here in the Philippines is too week, I'm here in my province full of mountains I will the 2.4 crosshair Xtreme in my wifi I will wait for your reply thank you very much my idol.
I really want to learn from you how to make my diy 2.4 crosshair Xtreme for my personal use only for my wifi, because the signal is too week full of mountains . I don't know your email because I'm new here thank you very much please reply my idol thank you and God bless 😊
Please send me the measurements of 2.4 crosshair Xtreme for my personal use only . I really want it so much because your really the greatest in dealing with making antennas I don't trust other people .
What is your Facebook and messenger? My messenger is Golden Hill,