This is the stuff every other Armature Radio RU-vid channel just glosses over because they think it's common knowledge without thinking of the newbies trying to get into the hobby. Thank you for explaining things in simple terms beginners can understand. This is also the best video I've watched on the subject! I didn't get into armature radio to nerd flex on other nerds. I'm into armature radio because I'm legitimately excited on how it all works. We all want more people to play radio with. Thank you again for helping more people get into the hobby.
Thank you, first time I think I understand the difference between UNUN and BALUN. I get lost quickly when David Cassler starts drawing on the whiteboard giving likely correct but very complicated answers to simple questions 😅
Different learning styles. I need to have the “why” stuff to internalize information. But I understand that most people learn better with technique vs theory. So this video left me unsatisfied. But it works for many (most) people. Awesome that we have so many Elmers right here in one place (RU-vid)!
@@Frisky0563 I like Dave. He's like a gnome in his workshop trying to explain the hardships of Santa to the elves. Honestly, I mean that in a good way. But yeah, he talks in his language from his perspective. I have noticed that sometimes even he isn't technically correct even if in a practical sense he is. I think it comes down to what people are familiar and comfortable with. I like gnomes. ☺Cheers.
@@mewintle I'm the same way in needing to know the why and how of things for them to fit and stick into their place in my understanding of things to see and figure out how things work in relationship with each other and what needs to be done when. While it isn't perfect of course, things such as the water analogy for electrical circuits have gone a very long way for me. Taking that further, RF is perhaps a bit like sonar... 🙊Cheers.
Walt, THANKS! As you know, I have been a long-time Ham, but I am new to building antennas. And you were right. This is the video I needed to watch. I have a list of notes to stick in my POTA case to help me in the field. Thanks again for all you do to help this amazing community. 73s.
Great explanation Walt, concise and to the point to help beginners understand the fine points of antenna building. This is why I really like and recommend the videos on your channel. Also that's a nice Hammarlund in the background, I have an HQ-160 that I have had since my teen years in the mid 1970s! I started out with it listening to shortwave in my teens and it stoked my interest in ham radio.
Thanks! I was heavily into shortwave in my teens as well. I got that HQ-180 by luck a couple years ago. My neighbor across the street found it in his attic and gave it to me.
@redstickham6394 @COSTALWAVESWIRES Similar situation here. I listened to short-wave in the late 1960s getting many DX broadcast stations using a long wire antenna in my parents attic. But I didn't get into Ham radio until very recently.
Good explanation. Many former Elmer's are smiling down on you from the great beyond. I agree that the KISS way of explaining things is the best approach.
Thanks Walt. That was helpful. I had a couple EE classes in college 40 years ago when I earned my mechanical engineering degree, but there was zero material about RF antenna design. A friend of mine has a MS in EE and even that didn't cover much about RF. It was mostly IC design and signal processing for him. If the terminology was unbalanced match and balanced match versus unun and balun that would go some distance. The next step would be describe the circuit in a balun and the circuit in an unun and explain why it works for each type of antenna, respectively.
Thanks! I’m not sure if RU-vid is ready for a structural design engineer to break down the circuit design of a balun or unun but I guess I could give it a try LOL. All the best and 73, Walt
I've been searching for a while now for a simplistic, concise, yet understandable explanation of UNUNs and BALUNs. You have provided it in this excellent video. Thank you so much for this. Subbed!
Simple, explained well for the beginner, your channel is great as its no nonsense to the point with simplicity, well done Walt. Im sure we all appreciate your time.
Walt.. Thanks for this.. I'm about to do a "Choke" video and was doing some research and this popped up! Still confused when I would EVER use an Unun..!! LOL
I keep revisiting this topic, and man, this was the perfect video for me to bookmark and keep coming back to!!! How do you not have 100K subscribers yet?
New guy here. Trying to build my shack and scared to death of lightning strikes as we get them fairly regularly. Antennas seem to be the most complicated part of radio. Proper grounding is the concern I'm trying to learn about most.
Many years ago (during my CB days) I learned a balun can be a really neat thing. But you have to be willing to experiment a little. Someone gave me a 4-element beam which had an insulated dipole driven element with a hairpin match (He did not know how to feed it). Not wanting to try and feed it directly with coax (did that with another similar beam one time with poor results), I decided to try and feed it with a 1:1 balun. Since the dipole driver would have a 75-ohm feed point impedance, I connected the balanced side to the hairpin, and used 75-ohm coax to feed it (not CATV coax). All I can say is 'wow'! Not only did the antenna work very well, it was also the quietest antenna I have ever had. The SWR measured at 1.3:1, and I could hear signals others could not, especially in dry-air Santa Ana conditions when the air becomes 'charged' and a lot of static is present. The hairpin match provided an awesome DC ground which, in combination with the balun, provided a virtually noise-free beam. I used it for many years before a wind finally blew it down. Wish I still had it!
Thank you Walt for giving me a good basic understanding of baluns and ununs. You gave me a good understanding of why they are used and what type of antennas these transformers should be used on. You gave me a great foundation to build on. Other RU-vid videos explain the windings and turn ratios, etc. without explaining why and where they are used. You are a great teacher/instructor. Thank you very much.
Walt, your videos are so great and easy to understand. Thank you for simply breaking this topic down and easy to understand. Where or how do you build that cool on air sign? That looks awesome!
Thanks for another really informative video. Where did you find that chart of the wire lengths and corresponding transformer? Also do you have a video showing when you might need a counterpoise, vs radials? Now that the weather is a little nicer I’m going to actually start building these antennas.
Great video giving an easy to understand explanation. When I got licensed, UnUns weren't really being used but now they seem to be pretty popular. I had a random wire(not sure how long it was) antenna that was fed with single wire that went straight into the tuner. I wonder who many hams still do that? It worked well but on some bands the RF in the shack made the rig go a little haywire if the power was up too high. Your videos are always informative. Keep up the great work.
Thank you so much! I’ve been thinking about building a long wire antenna with that TenTec antenna coupler I showed in the video. So it would pretty much be like your antenna you described. 73 my friend!
It is a coupler when the antenna is directly connected to the "output" end of the device. The coupler is typically remotely operated. If the matching device is close to the radio, and directly controlled, then it is a tuner.
Check your Balun/Unun. I bought a cheap 4:1 balun and installed it on a 17-5 antenna. Could not get the antenna to work properly. Narrowed the problem down to the balun. Took the balun apart and realized it was wired just opposite. It was a 1:4 instead of a 4:1. Simple to unsolder and rewired. That fixed the problem. SWR on 20 meters was less than 1.5:1. Probably rare problem but it can occur.
Thanks Walt, very much appreciated, now we have an idea why a Baluns and a Ununs is required....also explains why some home built antennas SWR OK work and some don't.
I think I get it - then i don't. UnUn makes sense for situations with an unbalanced match (49:1, 4;1 etc.). Then BalUn for 1-1 balance scenario (dipole example). But why would the Delta Loop not use a UnUn? It's 200 ohm t0 50 ohm, using a 4;1. Shouldn't that be an UnUn since it's unbalanced? YOUR CHANNEL HAS BEEN THE MOST HELPFUL/FUN/INFORMATIVE I've found. Can't express my gratitude enough. I'm on the list for a FX-4CR so I can't really start playing.
Oh wait, is the balance relating to the physical design of the antenna rather than the Ohms? Endfed uses an UnUn since the feed point is at the extreme end of the atennas, vs a dipole or delta loop where the feed point is in the physical middle of the antenna, and thus, sues an Balun. That would make sense. I hope I'm correct.
Thank you… my confusion is no longer there. Your explanation is simple and correct. Your material (IMO) should be thought and provided in our question pools. So many ridiculous questions that are not relevant. 🎙️W1FYG
Hey Walt! another great video! I like making my own, rather than buy them. When you describe the impedance in ohms, That is exactly how you test them. I have resistors soldered together that approximate the EFHW, Random wire, or delta loop. Connect them to the antenna connection and the counterpoise connection or to the shield side of the coax. Then connect your swr meter, and if they give a close to 1:1 reading, you know they will do the job. When you make your own, you can tweak the windings, and tune them up even more. Have you seen the Gabil GRA-HF750T antenna setup? You can turn your qrp rigs into an HF walkie talkie with these. Add a short counterpoise and they will amaze you.
Good simple explanation, I understand now the need and differences between baluns and ununs and what antennas they are used on. As a shortage listener only, will I notice a difference if I match the balun/ununs to my antenna type?
The Delta Loop raw impedance is closer to 100 ohm than 200 ohm. I've had better luck with a 2:1 balun and no tuner. Nevertheless a 4:1 balun will work... Txs for the video, very useful and well made. Keep on the great work!
And here I was scared you were going to pull up a Smith chart(kidding!). Thanks for the simplified approach of impedance matching coax/feed line to the antenna.
An antenna tuner is only an antenna tuner when it is at the antenna. Matcher is more like it. Nice video Walt. I got a 9:1 kit from Palomar Engineering years ago and built as there instructions as a unun. Turns out it was an 8:1 not a 9:1 and there reason in the directions was the core selection. years later and a lot more education. It tested as a 8:1 not a 9:1. It will work with a non resonant but it will not tune quite right. Live and learn. I sent them an email over this, we will see what happens. I will rewind it so it is a proper 9:1 and make it useable
So you helped build Ocean Beach huh? LOL..... Well you figured out the plans and the structures and I nailed them together. Started my construction career in Newport Beach back in 75 when I got out of the service. Lived on a boat in the back bay while learning to pound nails and string wire. 73 and thanks for the great video. Still a little to learn about these things. Like how do you determine the impedance of the wire you are connecting to the ballun as a driven element?
Thanks for commenting! Determining the impedance of the wire can be done with an antenna analyzer and also by modelling the antenna. I basically go with known lengths and trim to suit. It would probably a good idea to do a video on that topic thanks. All the best and 73, Walt
Please do because I don't know what you mean by modeling. Please know that I am old and come from the TUBE days. Having a hard time with all the digital crap for the general test because of that. Wish I had gotten my General much earlier before all this digital stuff. LOL...@@COASTALWAVESWIRES
The sum total of my knowledge as learnt for my foundation licence (oh errr !). UnUn - unbalanced to unbalanced . Balun - Balanced to Unbalanced. The rest is down to magic. 73 and Happy New Year to all.
Great explanation on baluns/ununs.....thanks!! For wire antennas though, are baluns and ununs primarily just a tool for connecting the wire to the coax....and doing that in a way that will closely match up the two with a transformer, (as well as to keep RF from making its way back to the radio)? I have my first HF radio on the way, and I ordered a manual tuner as well, since I thought it was a good idea to always use one. If I'm understanding correctly, the two options are....1) to use a balun/unun so you don't need a tuner and 2) to use a tuner with a choke so you don't need a balun/unun and just connect with a banana clip? In other words....using balun/ununs keeps the equipment to a minimum and gets you on the air quicker? Seems obvious now that I think about it.....but confirmation that I'm thinking correctly is appreciated.
Hey, me again. Just subscribed. Great channel. Working towards my first ham license in the US. Re the Rybacov, I recall you mentioning in your "10 best..." vid that it is a multiband antenna requiring the use of a tuner and also requires ground radials. In the case of your simple vertical rods inserted in a lawn/ground umbrella with the balun at the bottom, would I be right in assuming the radials should all be connected to the balun ground terminal and radiate out? As I've begun to understand, most verticals one buys commercially tend to have a metal ground plate at the base from which said radials, well, radiate. Thanks in advance.
Yes the radials or let’s call them counterpoise wires are connected to the ground side of the balun. Here’s a video I did a while back that describes “RF ground” which is what you are describing as “radiating”: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KjEOUZS_5sw.htmlsi=BJLIZXMHbPqJTrqN
I think the simplest explanation is that a balun matches a balanced element to an unbalanced element. And an unun matches an unbalance element to another unbalanced element. I hope that helps. 73 Tom KC3QAC
Thanks so much, Walt. This is the video I have been *dreaming* of for a long time. I was so confused about this. Now I'm starting to understand how this works. This video will be of great value in my attempts at building antennas for portable operation. I have a question though: what about a 1/4 wave resonant antenna with ground plane (or radiants)? You didn't mention this one. I presume what's needed is a unun since it's asymetrical, but with what ratio?
Hi Alain, great question. Have built 1/4 verticals without a balun or unun and they have worked great. I have a couple old videos on this but this one explains it simply: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-BJXI4baYBok.htmlsi=vcfue-rqYnp_TMdw A perfect 1/4 wave with a ground plane would actually have a 1:1 unun at the feedpoint as a 1/4 antenna typically has 50 ohm impedance. I hope that helps. 73, Walt
So does that mean that the antenna tuner is doing the same matching, but between the transmitter and the coax? I guess the impedance of the amplifier output would change depending on what frequency you've selected, and that's why you need a whole other device? Because it seems that transmitter manufacturers could reasonably predict that 50 ohm coax is what they're gonna see on the output side otherwise. Maybe you could clarify antenna tuners in another vid, but this was really clear and simple for explaining the un/bal-un concept - thanks!
Thanks for watching. Yes the tuner is pretty much doing the same thing at the feed point. Basically with the random wire antennas and the 9:1 the idea is to get the match close enough for the tuner to somewhat "fine tune" it. Great idea, I'll look into doing a video on antenna tuners. 73, Walt
An excellent explanation as always Walt. It makes sense to those who don't know. However, there is one basic assumption that most YTers make, they assume that a budding antenna builder knows what the impedances are to start with for a prticular aerial configuration, I recall I think DC showing a dipole fed in the centre = 50 ohms and then moving the feed point to one end until it became an EFLW and the impedance was as high as it was "going to get". Obviously the baluns for this would start at 1:1 going through 4:1, 9:1 and so forth on to 49:1, maybe that is a reference diagram that needs drawing by somebody? Then there could be coverage of those in the 64:1 range or special configurations? Just a thought - 73 de Terry
Maybe there is a market for a digital power meter that shows SWR and the impedance figure? I know that you can get meters to measure the impedance, but to have it on a straightforward 3 in one meter (that doesn't need a tutorial to remember how to drive it every time) would be a handy bit of kit? @@COASTALWAVESWIRES
Great vid' , Walt... What would you recommend the LDG 49:1 or the 9:1 UnUns for the field bag? What are your thoughts on the construction of these units? I've heard some sketchy stories about some of their builds. My MFJ-945e tuner works great...
Thanks! I have all the LDG transformers except the 49:1. I think they are great and would definitely recommend them for the field bag. I’ve never had a problem with them and they’re pretty much all I use. For a 49:1 I use a TennTennas build and it is great as well.
Hey Walt, happy new year! Hope you had a great holiday season. Silly question: I have a 49:1 balun on a random wire. I have no idea of its actual impedance. Is there such a thing as "too much balun"? If my impedance is 600 and I'm running 49:1 then this works out far less than the 50ohms needed. Is that detrimental in any way or can 49:1 be a one-size-fits-all? What's the best way to find out the impedance of an antenna? Thanks again!
Happy New Year! That’s a great question and there are a lot of variables to what you’re asking. Yes you can definitely have “too much” balun but there are simple ways to figure out if you’re good. The simplest is to just check SWR, good low SWR pretty much means you’re good to go. The proper way to check impedance is to use a VNA or Antenna Analyzer and check the feedpoint. I say if it’s working and your SWR is decent, don’t overthink it. Fire up that radio and start making some contacts!
I've been trying to find how to calculate that for years. I've always thought the equation would be way more complex. I thought you'd need to know if the impedance mismatch was capacitive or reactive. Gee so simple.
Great video Walt. Your simple explanations of these technical subjects really help my simple brain to understand them. Perhaps you or someone else can help me understand where these feed-point impedance numbers come from. You state that an efhw wire has an impedance of 2450 ohms and requires a 49:1 unun to match it to a 50 ohm coax feedline. Thats great and I understand that much but how did you get the 2450ohms for the feed-point impedance? Is there a way I can measure feed point impedance with my AA-35 or a Fluke multimeter? How do you know a random wire is 300-600 ohms impedance? If I were to stumble upon a "random wire" that I wanted to try and use for an antenna, how would I know if I need a 49:1 or a 9:1? Ultimately, I'm sure I could hook it to either and tune it to get a match somewhere on the bands but how do I know? lol I get this is probably something very simple to all the engineers and tech guys, but I am neither.
Thanks for commenting. Yes I’m sure you can measure feedpoint impedance with your AA-35 but there really isn’t a need to. Just know that most half wavelength wires have an impedance close to 2450 so a 49:1, 56:1 or 64:1 is typically what is used for wires nearing or around a half wavelength. As for 9:1 ununs and lengths check out this site: www.hamuniverse.com/randomwireantennalengths.html That really explains it. 73 and all the best!
Imagine the current distribution along a half wave piece of wire. It's half a sine wave with the peak in the middle and the nodes (no displacement points) at the ends. You have maximum current, minimum voltage in the middle, so you have the lowest impedance, around 75 ohms, depending on how high the wire is above the ground. As you move towards one of the ends, the current decreases with the sine wave and the voltage increases. By the time you get to the end you are at the voltage high and current low, with the highest impedance, which could be 2000-3500 ohms, matched with a 36:1, 49:1, 56:1, 64:1 or so transformer, depending on band, height above ground, nearby objects, etc.
@@paulsengupta971 yes, I understand that but I’m asking how the impedance numbers are derived. How do you know that a wire of a said length has said ohms of impedance? How is measured or calculated? Where did the 2450ohms of impedance come from?
Walt, do you have good luck with the LDG baluns/ununs? I bought a 1:1 choke/unun to prevent RF problems with my portable setups and while it worked for that, it also made my antennas behave in unusual ways. They no longer tuned up correctly at the frequencies they were designed for, so I became suspicious of the choke. So, I attached a 50ohm dummy load to one end and a NanoVNA to the other and was surprised that with the choke inline, the SWR rapidly climbed with frequency, hitting about 2.5:1 on ten meters. I opened up the choke case and found it was rather shoddy inside...and odd choice of winding method, overall sloppy winding, cold solder joints and the core was only supported by the soldered wires. There was a piece of double-sided tape inside, but it wasn't touching the core! This surprised me, as LDG's tuners are build wonderfully, very solid. Anyhow, I replaced the core with a FT-140-43, wound it with 11 bifilar turns (with a crossover winding in the middle) and now the SWR is completely flat across the HF bands. I'm a big fan of LDG and they have been VERY generous to me with their support, in both time spend and even sending replacement parts free of charge. Great company, but this choke was sure a disappointment.
Thank you for your inspiring video. I am starting with HF and have space for a End Fed Random Wire of about 12 meters. I hope this will give me some possibilities on 10, 20 & 40 meter. How do i measure what the impedance of that wire is, so i know what ratio of Unun i need in order to transform it down to 50 Ohms. Thank you and 73's ... Bert
This video helped me for sure. One thing that would have made it the GOAT Bal/Un/Un video would have been to tie in the mantra that you should just try it. Show us the impact of no Bal/Un and then show the beatiful matching impedence after. So, will you still make a contact using a 4 to 1 instead of 9 to 1? Will you make a contact with a 49 to 1 or without?
The real question is “would your transceiver’s tuner tune the antenna with a 9:1 instead of a 4:1 or 49:1” the answer is probably not because the purpose of using a 4:1 versus a 9:1 versus at 49:1 is to make the feedpoint impedance as close to 50 ohms to match the coax and radio. You may even be able to tune one of the others with a different transformer but have greater loss in the coax and out of the antenna meaning not making that contact.
@@COASTALWAVESWIRES the good news is, I totally understand now. In theory anyway. I'll be putting it into practice very soon! Love the videos. Keep em coming.
Question, most of your videos assuming multiband and Ham radio, but with CB gear suddenly a SHTF issue, i keep having people ask me about low profile antennas. The flagpoles with tuners are insanely expensive for what you get. May i request you make up the best performing low profile antenna for CB / 11 meter use and hopefully would do as well at DX as a 10 meter you will already have made. Name the video keyword well and you will get a lot of traffic. You make great videos and are a true walking library of useful info and experience.
Hi Walt. Happy New Year. I noticed that at 3:58 you said a dipole has an impedance of 50 ohms, but I think that is for an inverted-V antenna. A dipole is 73 ohms. I've heard that many hams in the days of tube rigs used 75 ohm coax (TV type) and just tuned their tube transceivers to match that without a tuner. So with a modern 50 ohm solid-state rigs, would SWR on a resonant dipole be lower when using a 1.5:1 balun instead of a 1:1 balun? This would drop the impedance from 73 to about 50 and produce the lowest possible 1:1 SWR at resonance antenna length for the frequency in use, right?
@@COASTALWAVESWIRES I love the way you explain things in a very approachable way. I definitely learn something from your videos every time I watch them. That's what is great about ham radio. It is a hobby of continuous learning and experimentation. It brings out the playful kid in me......which is a good thing.
The actual feedpoint impedance of a resonant dipole depends on the height of the wires above the ground, how they're routed (straight, bent, angled up, angled down, flat, folded back, sloped, etc) and how conductive your ground is. That's why changing the wire height above ground by going from flat to inverted V changes the impedance. In other words, it is extremely hard to predict, so you can't really say a real life dipole will be 75, 50, 150 or 25 ohms until you put it up and actually measure it.
