#131

[@BGLENN-dp4tx]

Peter, I can't thank you enough for the 4-part video series. For my all-band, home brew open-wire feeder and 80 m loop, I needed to "tame" the impedance it presents across the HF spectrum. I "swept" the antenna, checked the data, and decided that 9:1 transformations would do what I wanted. So, last night I watched your 9:1 video and as you went along, I wound mine step-by-step. Then at the end of the video you stressed that a 1:1 current balun was required for CM attenuation (and balanced input to the 9:1) and so I watched the 1:1 build that you also provided and I built one as you described. Today and tonight, I performed a VNA sweep of the baluns to confirm performance and then placed them (interconnected) back-to-back into a CANTEX utility box (with SO-239 input & threaded-studs on the output). I tested the balun combo with my all-band antenna and on the HF bands at power levels up to 250W on all bands from 80m - 10m (fine tuning, of course, with a little help from the tuner). The baluns' performance was superb and transformed the wild impedance swings of the multi-band antenna transforming them to be within the performance specs of my matching network! I checked the "balance" on the feed line and it was ideal - far superior to the common 4:1 balun in many tuners. As a result of this two-day project, there is no more obvious signs of CMC and/or RF floating around the shack, and/or higher-than-normal noise levels. In conclusion, the balanced output of this new configuration works even better than my bare-bones Palstar BT-1500A, in my experience. THANK YOU for your contribution of time and effort. It's very much appreciated!! 73!!

[@SrkSukoi]

I am very grateful to Mr. Peter - TRX LAB - for the information that helped me solve this balun issue using the FT240-43 ferrite. I followed the guidance and managed to make my balun. I am very happy and impressed with the performance. Congratulations on the initiative and all the benevolence. 73 from this humble radio ham

[@keithpetherick3425]

Saw a comment from me that I wrote 7 yrs ago. Have had your common mode choke at the base of my hexbeam for what must be 7 yrs now. It has served me well. I have now removed it to try snap on ferrites no 31 instead of a torroid. Have now started to experience swr problems on 10m and 24megs. I am going to put the torroid one back. Anyway 7 yrs later, I am still returning to your videos for reference and an aid to my memory. I have nearly completed this 9:1 torroid, but I am putting two cores together to try to avoid heat. I am waiting for some ptfe wire to arrive for the common mode choke. I tried some cheaper silicon wire but found it was too fat to wind on the torroid. I am going to put these on a random wire antenna for the lower bands. I might use a 31 mix for the common mode because I want to get back on to top band. Up until last year, for top, 40 and 80, I just used a wire with the feeder wrapped around 4 stacked 240-43 torroids at the base of the mast, tuned at the atu in the shack. That worked well but came to grief in storms. Also I am thinking about the emf regulations so that is why am refering to your work. I will be able to put these torroids at the top of the mast, and hopefully I can avoid radiation from the feeder which now would be inside the regulation exclusion distance. Thanks again for the tuition Keith G0ODU

[@mecee4516]

Keith, I hope you see this... I bought some PTFE & wasn't getting the results I expected. I used a potentiometer on one leg of the 1:1 CMC and found the match was 150 ohms!! I remembering separating feedline conductors increases impedance I realized the PTFE insulation was too thick. So I ordered more PTFE, with thinner insulation. It worked!! a little tweaking of the newly wound spacing got 100 ohm per side, and a nice 50 ohm with both in parallel. An interesting journey. Good luck with your new build! 73 de Noel ZL1NC

[@albertvanduren1693]

Peter, thank you for this comprehensive analysis and amazing content. I keep coming back to this series because it is such a great reference. 73, AE0JT.

[@nightsquatch709]

I know I am just repeating what so many others are saying, but thanks you! Your balun series is the best series on the subject, anywhere. I am also one of the many really hoping you will make a 49:1 balun video. Fingers crossed. =)

[@dennisbauer3315]

Thank you again Peter, this is the best series on baluns any were on the internet, and I too keep going over them, a big thank you 73 from VK4JDJ

[@iaahner]

Best series on baluns on youtube! Waiting patiently for the 49:1 or 64:1 unun video. :)

[@aerofart]

For a 49:1 or 64:1 you would follow the same concept as you see done with this 9:1. The important idea is that the impedance match is equal to the square of the turns ratio. So, for a 9:1 match, the windings are 3:1. For a 49:1 match, you need a 7:1 turns ratio, and for a 64:1, you need a 8:1 turns ratio. The number of total turns on the high side of the coil doesn’t matter as long as it fits on the core, and is divisible (you can tap into it) by the ratio value that you need. So really, a 3:1 turns ratio can be a winding with 18 turns, tapped at 6 turns (1/3 of the total) and 12 turns (2/3 of the total) to get your inputs. The ends of that 18-turn coil would go to the antenna. With a 49:1 or 64:1 you would need either a larger core or smaller wire so that you could get 21 or 24 turns onto the core, tapped at 7 and 14 for the 49:1, or at 8 and 16 for the 64:1.

[@ronlouis3011]

I find watching these videos is very relaxing and educational. They are so much better to spend time with instead of television or sports games or news. Thank you for the work you put into them for the benefit of us technicians in training around the world. I particularly enjoy watching your method and final solution.

[@TRXLab]

Thanks for the kind words Ron! 73

[@acestudioscouk-Ace-G0ACE]

I'm watching this series of videos for the second time because there is so much good stuff to learn, I need to watch it at least twice to take it all in. You have put a lot of work into this and I'm very grateful. I wonder how many people you have saved from radio interference and how many rigs you have saved from too higher SWR! Thank-you.

[@aerofart]

This is my second time watching as well. I recently completed a course for electricians, where I learned a lot about transformers, so watching it the second time really solidified my understanding. It also helps to draw the device out in a traditional schematic diagram form.

[@PixelSchnitzel]

This is an excellent series that I'll be referring to many times in the future!

[@TRXLab]

73Thanks for the feed back

[@nigelsookdeo6880]

Yes the best and most detailed. You are truly the best teacher, I always learn things from you I have problems learning on my own. Wish I can come be your student.

[@ianboard3555]

I just wound it and it worked out well - I got less than 1.3:1 from 1 - 30 MHz. I'm thinking that the key points here are the even and maximal spacing of the windings, minimizing parasitic capacitance and keeping the leads short, minimizing stray inductance. I wound it on an FT240-43 core with 18 AWG wire (all I had, but I'm never going to be using it with more than 100W). I just wanted to thank you for the detailed instructions

[@billrutz9851]

Your Videos are great. I have learned a lot about toroids and setting up Baluns. Have you ever thought about doing a series on 49:1 Baluns /UNUNs for EFHW antennas?

[@joseico90]

Thanks Peter, I appreciate the effort you put into these videos, being new to HF I do prefer the "proper" engineering approach you use. I am following your examples and very much like to see the testing you do, no guesswork here, as it should be, well done. Best Regards.

[@HAMRADIOBRASIL]

Hi Peter. I'm completing a 9:1 Balun just like your video, however, with FT-140-43 toroid. In an initial analysis on NanoVNA, the SWR from 1.8 to 54 Mhz was practically between 1.0 to 1.3. As soon as I finish the balun, I'll be posting it on my KZbin channel. 73 and God bless you.

[@ssbfmcw]

Peter thank you for this very practical tutorial on using toroidal core auto transformers. You have provided me a eureka moment (actually several) in this part 4 video. The first is the method of adding friction to hold the windings in place, second is how to evenly space the turns using indexing, third placing the primary winding in the center of the coil to produce a balanced input and output, and fourthly but not finally, insight to calculating turn spacing. I do admit to having to watch the segment beginning at 19:50 three times as at first I thought these 8 turns were being wound in an opposition sense to the first 8. I will apply some of the techniques you present to constructing an auto transformer to match unbalanced 50 ohms to unbalanced 4000 ohms (end fed half-wave or a bisquare antenna). This will require a 9:1 turns ratio so my first attempt will be 3 turns for the 50 ohm port and 27 turns for the 4000 ohm port. I will test with an MFJ 259 analyser as that is what I have. Thanks again for both the instruction and inspiration.

[@TRXLab]

Glad that you like it Bill and thanks for your detailed feed-back! 73

[@jimf1196]

I tried this on a FT140-43 core and it worked great. SWR was under 1.25 over 3 to 30 MHz and it was pretty much flat. I also wound a more typical 3 wire 9:1 unun very carefully on the same core and it was much much worse, especially at the high frequency end. I used insulated 18 AWG wire because that's what I had and it still worked great. Thanks.

[@keithpetherick3425]

Excellent info. Now how do I get the wire antenna over the trees in my garden?

[@richarde735]

so viele wundervolle Dinge in Deutschland von der Feinmechanik bis zur wunderschönen Landschaft! Peter, vielen Dank für dein Fachwissen und deine Bereitschaft, dieses Fachwissen mit dem Rest von uns zu teilen! Haben einen gesegneten Tag!

[@rudiimbrechts3064]

Just made mine according to your excellent instructions. My miniVNA even measured slightly better SWR so I'm very pleased with it. Thanks a lot and 73 de ON7IR

[@stanholmes4293]

Hi Peter How do you calculate the number of turns required for the 9:1 UNUN? Thanks for all your interesting videos

[@herbiegraham9549]

hi peter great detail on baluns i have built the 9 to 1 and under test of 1 to 30 mhz the highest swr is 1.23 . best preformance of all the baluns i have built thanks again

[@cesziek4731]

Thank you very much Peter, very educational! Now I can start to make my own 1:1 and 1:9 balun!!! More power to you!

[@jesustillero]

Greetings... excellent series. Is there any chance that you can activate the subtitles for videos 3 and 4? thanks!

[@mowtown75]

Again thank you for a great tutorial. May I ask please how then do we cut the long wire to resonance because the transformer wont let u see the antenna properties.

[@johnpeterson7264]

Does the cloth tape also provide insulation - preventing the wire from shorting out through the toroid ? The enamel insulation on the wire seems unlikely to oppose the voltages involved ? Thanks for an excellent video.

[@dzboyovsky]

@trxlab . Im building your 9/1 unun. I'l looking forward to launching a long wire over the Oak trees in my backyard. So, I would like to have 160m through 10m if possible and with all the talk about random wire antenna lengths, I believe I have room for 500+ feet wire lengths. do you have any ideas on wire lengths, is longer better and should I use ptfe or solid core and what gauge? Do you have a series on long wire antenna lengths? thank you for your time and I very much enjoy your series.

[@izzzzzz6]

I've thought of a Part 5 Would it be possible at some point to cover how to wind an Unun or the difference in a 1:1 Balun and a 1:1 Unun as a CM choke (into say a vertical)? Also I would love to see some more transformations such as 50 ohm to 75 ohm. Thanks again. I'm thinking to build a magnetic loop for a friend who has a terrible noise floor. The impedance would be around 450 ohms so I would use one of these. But the matching network of the antenna itself consists of a capacitor and sometimes an inductance arm that can connect to different parts of the loop to help match it. I imagine if the magnetic loop is only being used as a mono bander then a transforming balun may be all it needs to match it?

[@DuhBiggestDog]

Peter, thank you for an excellent video. I am a subscriber and routinely use the information you provide to assist me with my projects. I just completed winding this balun. My testing showed a VSWR of 1.0x all the way up to 30 Mhz where the VSWR was 1.3. I used a ft-240 mix 61 core. The tips you provided with the dots and the cloth tape were very helpful.

[@TRXLab]

glad that you liked the video! Thanks

[@ralph9987]

Danke dir fuels video. Habe gerade ein 9.1 gewickelt aber jetzt bleibt mir die frage welche der Anschlüsse ist der Strahler und welches der Counterpoise/ground ist. Hilfe bitte.😊

[@TheFatboyaudio]

HELLO FROM GREECE..THANK YOU FOR THE DETAILED VIDEOS...PLEASE TELL ME HOW YOU DETERMINE THE POSITIVE AND NEGATIVE POINT FOR THE 50 OHM AND THE POSITIVE AND NEGATIVE POINT FOR THE 450 OHM ...REGARDS...

[@larryk4mu240]

Hi Peter, Awesome video. Very clear instructions. If followed, anyone can have a great preforming balun. I’m sure this series of videos will be referenced many times. Thanks 73

[@TRXLab]

Thanks for stepping in Larry! 73

[@mikesradiorepair]

A solder pot works great for removing the enamel coating off the wire. Added bonus it tins the wires in the process.

[@TRXLab]

You are so right Mike, should order one but do not often need it.. 73

[@simov8chevy]

@@TRXLab I use an old brake caliper piston filled with solder and heated on a gas stove. Use it once in a blue moon but very handy.

[@vu3sxe]

Thank you in advance Peter, this was fantastic to watch.

[@DOCCCGAL]

Thank You very much for your really informative Videos! Folgende Fragen habe ich: Durch die zusätzlichen Wiederstände in der Messung entsteht eine zusätzliche Dämpfung, von einigen dB, die man z. B bei der Messung mit einem Tiny VNA als Korrektur vom dort angezeigten Wert wieder abziehen muss. Ich habe diverse Werte fuer 1:1,1:2,1:4 bis 1:12 Baluns gefunden, z.B. bei DG0SA. Wie werden diese Korrekturwerte eigentlich genau berechnet? Oder als praktisches Problem: Wie berechne ich z. B. den im VNA abzuziehenden Korrekturwert bei der Messung eines 1:64 UnUn fuer ene Endfed Antenne, die in der Messung mit 3200 Ohm simuliert wird und z. B. auch noch eine 1:1 MWS davor hat, deren Mantelwellenstrom fuer die Messung durch 2x25 Ohm auf Innenleiter und Abschirmung erzeugt wird - wie im Video beschrieben? Vielen Dank fuer die wertvollen Tutorials! 73 de DO1CCC

[@abelatan]

If possible, can you please provide informaiton on makiing 2:1 balun? Probably just the number of windings.

[@RickCoker30564]

Excellent job Peter, I finally understand the concepts! You are an excellent teacher.

[@TRXLab]

Thanks for feed back really glad that my videos made sense to you 73

[@tubeDude48]

What's that work out to wire gauge?

[@geirha75]

one more question on building 1:9. what happens when adding more turns?

[@ae1tpa92gwtom2]

Always Enjoy yr channel Peter,. Thankyou for propagating this knowledge, have watched the entire series, 73

[@TRXLab]

Thank you!

[@ianboard544]

I wound the 9:1 unun and 1:1 balun according to your video (I gather they are used together). How do I connect them? Connecting the 1:1 to the feed line seems clear enough, but does the orientation of connecting to the 9:1 matter?

[@g4okt]

Wow, thanks Peter, I just finished my 9:1 transformer, by watching this vid step by step. Though not as neat as your job (yet), I get very similar SWR figures on my AA-200, excellent result. Thanks you so much! (73 GW4OKT)

[@royhopkins974]

I need a 16:1 balun and understand I could use two 4:1 balun in series 4x4 = 16. I intend to test this as the 4:1 balun I made works very well according my nano vna. I tried making the types of 16:1 shown elsewhere, but the rest was o ly good up to 4 Mhz. Or if you have a different way, please demonstrate or provide a link.

[@norbertstepien9185]

Excellent video...thank you. Peter, I have one question, how to hook up the two wires to a single longwire antenna? The HyEnd wire antenna has only the wire attachment to the balun box and no counterpoise, can this be duplicated with this transformer design?

[@slimh2080]

Hi Peter. Another great video series. you keep putting out some of the best vids out there. I will tell you one of my secrets for 9:1 Baluns. I use a t150-52 iron core with 10 or so turns. and is flat across all the hf bands You will find these in many switch mode power supply's. Green/blue toroid. and at 1/4 price. I haven't used these above 125 watts but they work for me. I also use some of my beldon 83336E stash I have. Keep up the great work!

[@TRXLab]

Thanks for feed back and for your hint! All the best 73

[@N2RRAny]

As always, great video. Enjoy your attention to accurate detailed workmanship. Does the type of insulation for example, THHN electrical wire insulation on 14awg solid matter in winding a balun lets say a 1:49, or some refer to as a 49:1 unun? Will it create resistance and change not only impedance in the balun, but wire length of 1/2 wave efhw. How would electrical wire using THHN insulation effect making a 49:1 unun and what would be the suggested distance between the outside of the windings of a 49:1 unun IF that type of wire is used?

[@wallyhandyman]

what size is the transformer wire used in this 9:1 video? 18 awg? and great video's on this you helped out a lot thanks.

[@TRXLab]

Hi Wally, yeah 18 AWG will work fine. Thanks for watching 73

[@wallyhandyman]

well thank you for your reply great job keep it up.

[@wallyhandyman]

May i suggest a video in how to make a 2:1 balun.

[@TheRadioShop]

Another great video Peter. I really like the way you explain this tutorials. Thanks for sharing. 73

[@TRXLab]

Thank you Buddy this is highly appreciated my friend. Take care 73

[@paulhastings3109]

Peter great content. The whole time thing you was making a 49-1 guess I need to see the rest of the Series

[@alans8963]

Great video Peter please provide a schematic of the 9:1. 73

[@TRXLab]

Hi Alan, finally it is a simple autotransformer like the 4:1 in part 3. Hope that helps 73

[@Argo16x]

Hello Peter, thank you for your very interesting videos. I particularly appreciated the BALUN series. I'd like to add my request for a 49:1 and 64:1 transformer's for end fed antennas tutorial.

[@TRXLab]

Thanks for feed back. I'm sorry have not the resources to deliver on your request. 73

[@Argo16x]

Thank you anyway.

[@yTb2801082331]

Thank you very much, this is what I was looking for ... a very well done video with great explanation on how to build a perfect 1:9 balun !!!

[@enriqueperi7056]

Thank you for the very slow and complete explanation! ... Too bad you don't enable the subtitles!! My English is basic, and I can understand it by watching it 2 or 3 times... ! Well that's how I practice English!! Most baluns fail because of something as simple as the correct spacing of the turns! -Very well explained!! ..73 and DX's Enric, EA3FSU.😅

[@Cardassiaprime]

Wow, this is the best series on baluns and common mode attenuation i have ever seen. I have already built the 1:1 and the 4:1.(Wunderbar) The 9:1 is next, I would really like you to do a build of Wolfgang's the 6:1. Vielen Dank Peter fur diese Serie. Barnie M7PBX.

[@garykanitz2826]

Hello, so I really enjoyed parts 1 through 4. Now the remaining question for me is how to build a 2:1 balun for use with a full length loop. All the sources I've looked at so for say they run about 100 ohms at the connection to the antenna. So I'd need 2:1 to get 50 ohms on my coax. Also any thoughts you have on appropriate use of ladder line to get the balun closer to the shack and use less coax for this application would be greatly appreciated. Thanks!

[@enzobisconti8089]

Hi Peter, I mounted the 9: 1 balun as you described it. I want to use it with a 16.20 mt longwire Where should I connect the cold pole of the 450 Ohm antenna? Must be connected in the cold pole of the rtx at 50 Ohm ?? Thanks 73 of IT9UMH

[@ianboard3555]

It seems like one of the main points is that you space the tri-filar windings as much as possible. Is this to keep the inter-winding capacitance to a minimum?

[@dimitriskamanas5804]

Dear Peter thanks for all valuable information given to this video series. Is it possible to attempt a 1:49 Balun for high power as well? Thank you in advance and please keep doing the really good work

[@gerrytrouse4074]

could we please have an update on the this with the use of the 49:1 balum ,efhw antennas ,with common mode using the vna for testing as a lot of us are now using this setup 73 gerry

[@TridentMissileTech]

Excellent tutorials. Best I've seen. Plan on watching them all

[@nick325ace]

I made this Balun and it worked perfectly. Thanks for showing me how!!!

[@TRXLab]

Glad that all is working fine and thanks for feed-back Nicholas Cheers

[@sneakers0]

can this be used as a unun by grounding one leg of the output or would the output tap need to be changed? A video on unun would be great.

[@yTb2801082331]

I've one question: Please, do you know how to block the toroids? I saw some kind of black special resin (no RF effects), around the web, but I don't know the model and where to buy it

[@TRXLab]

Hi Andrea, what exactly do you mean with "block the Toroids"?

[@yTb2801082331]

@@TRXLab I mean... to fix the toroid with the box... to avoid little movements 'cause of lottle vibration (from wind for example)

[@TRXLab]

Hm don't think that is necessary may be this info helps a08.veron.nl/zelfbouw/antennes/800-watt-fd4-multiband-antenna-with-super-balun/

[@yTb2801082331]

@@TRXLab Thank you!

[@MountainRaven1960]

I put together a 1:9 unun as per instructions here. When I tested it with a 448 ohm resistor chain, the VSWR was 1:1 to 1:2 from 1 to 30 MHz. Suffice to say, I am very happy. However, besides testing it, he doesn’t go into how it is supposed to be hooked up to an antenna system.

[@MIKEYDREAD1]

I am trying to get the same answer. did anyone figure out the 1:9 unun output which is hot and ground. Thanks in advance for any help.

[@jk3844]

Thanks a lot for doing this informative video. But, I do have a question. Would someone please comment and diagram the 50 ohm and 450 ohm connections as they relate to signal and ground. I just want to make sure that I have the input and output connects made correctly. Thanks.

[@vu3sxe]

I have a thicker core 1.6mm inside out thickness, 2.5 inner circumference, 2.05 thick/height, outer circumference 5.7mm - can I use this core, if yes will it be the same 6mm gap? I will use 1.5 thick wire.

[@calbrabandt5967]

I used a doubled stack of 240 cores (2.4 OD / 1.4 ID) and found the gap between the center wire (on the dot) and its two neighbor wires needed to be 4.5mm instead of 6mm for the best SWR on my nanoVNA Plus 4 so it's possible that changes in toroid dimensions will make a difference. I too used 1.5mm magnet wire.

[@delron44]

This is brilliant , totally sorted my tx problem out, also on rx, it seems a lot quieter . thank you so much.

[@ianboard3555]

What type of ferrite are you using? Did you mean FT240 for the size?

[@bill0047]

Maybe I missed it, bare copper wire is 1.5 MM which is 15 gauge. is 14 gauge acceptable?

[@das250250]

Notes - could you print paper template for the torroid ring with the spacings marked on both sides so the windings can be placed accurately without pliers damaging insulation ? Also, maybe a very thin 3d print which wraps torroid for wire guides like a screw thread for ultimate accuracy?

[@joseico90]

Peter, should I use enamel coated copper wire as shown here, or the PTFE coated ones in previous video? I need to buy one or the other so I'd like to know, thanks!

[@BobDarlington]

At 4:12, you say the toroid is an FT-200-40. Did you mean T-200-40 powdered iron? or what you were using previously, the FT-240-43? I have both and don't want to goof this up. Thanks!

[@BobDarlington]

I figured out that you meant FT-240-43, and not the T-200-40. Thanks for doing this series! - N3XKB

[@MattHeere]

This is an interesting design for 9:1. You're feeding the auto-transformer across the middle of the three windings, where most 9:1 UNUN feed across the 1st of the three. I wonder what the result is in a typical application using an end fed "random" wire where you ground the other 1/2 of the output? With the traditional design one connection is already at ground anyway because the coax shield is there. Not sure how it ends up with ground connected to two different places in this setup. I'll have to try it out - and great stuff as always Peter.

[@MK-wt8sx]

Where do I connect so239 and what about antenna radiator wire and caunterpoise. Great video thanks for the explanation

[@petergechev9466]

Hello, thanks for the detailed video. In order to make 1:9 baloon, is it necessary to have the exact same core, or I can use other diameter cores?

[@TRXLab]

Anything has an impact on the performance and I can only guarantee the performance on the tested parts..

[@calbrabandt5967]

@@TRXLab Very true! I suspect that my two-core 1:9 windings (FT-240-43) is the reason that I found 4.5mm instead of 6mm spacing to be optimum, but I desired higher power handling. Everything else was the same and I used 15 ga. magnet wire (almost exactly 1.5mm) as you used Peter. Thanks for the FB videos and 73!

[@StephenKangas]

Peter, excellent video series! I have referred my ham friends to you who I've inspired to DIY ununs/baluns. Question: you recommended PTFE wire for your 4:1 and 1:1 projects, yet in this 9:1 project you are using enameled (lacquered) wire, why is that? PTFE provides both superior heat and electrical resistance compared to enamel insulation, and in the case of an end fed random wire antenna that uses 9:1 transformer the voltage will be at its highest at the feed point, which can reach a high level (ditto for end fed half wave antenna that uses 49:1 transformer). The 4:1 and 1:1 balun project videos (I watched all those) you use PTFE wire in transformers that are typically used with center-fed dipoles or loops where feedpoint voltage is at its lowest (and current highest). It seems quite opposite recommended wire to me. With that said, I have typically used enameled wire for end-fed antenna transformers in QRP applications, which of course would be relatively low expected voltages, but here in this 9:1 you are talking about 800W and above? What say ye?

[@akdenyer]

Hi, is it possible to still get that mini VNA?

[@andrewkaufman1081]

I enjoy the series however do not have data on the core you use . Or where to obtain them

[@j390fe]

www.amidoncorp.com/ft-240-k/

[@TRXLab]

Hi Andrew, thanks for watching. You question has been answered by Jason already. Thanks to Jason 73

[@sorinparlog]

Only you specified that you used material 43 and not K. According to Amidon these are very different materials.

[@Mr_Meowingtons]

look at his part 1 he talks about it...

[@bobskimaxx]

German precision at it's best! Great video! Thank you

[@TRXLab]

Thanks Bobby!

[@davidw460]

Thank you for your efforts doing this series, it has been am inspiration for me to build things again. There is no doubt these work :)

[@aerofart]

Nice illustration of how to build a transformer. It would have been even better to see a traditional circuit diagram of the device. As far as I can tell, this is an auto transformer with input taps at 1/3 and 2/3 of the total winding, with outputs spanning the entire winding. So if I’m not mistaken, here we have two, 3T:1T auto transformers in this one device. And 3:1 turns ratio results in an impedance transformation which is the square of the turns. This really would be easier to visualize with a traditional schematic component drawing.

[@noelbulls8628]

Can this balun be use with random wire and a counterpoise ground radial?

[@craigpeters5087]

Hi, I have heard load's of people raving about this 1:49 balun which is supposed to be brilliant and can work an end fed half wave across multiple bands but I dont understand the concept, could you explain the science behind it ???

[@richarde735]

only one 240-43 is needed to handle 800-2000 watts? I was lead to believe that you should wind around two or more stacked ferrite cores. I just purchased a 1000w amp and I want to be sure.

[@noelbulls8628]

I would stack 2 ferrites and glue them together. He did said that in the video.

[@arturmoreira5808]

Hello, good evening, how are you ? My name is Arthur, which balun would you recommend for a 42 meter loop antenna, which balun model? my antenna is coupling 14 mhz 21 mhz, 15 mhz and 7 mhz. thank you Arthur ...

[@matthaxx7137]

Thanks for the video. Can you explain why you used three wires? Why can you not make 24 turns with one wire and simply tap the coax inner by soldering to turn 8? Isn't the magnetic field generated by the signal uniform throughout the ferrite core? Also why is this a 9:1 transformer if there are 3 x 8 turns. Why is it not 8:1?

[@davidw460]

Matt Haxx Hi - with this winding method we get 8 turns primary and 24 turns secondary, so a 3:1 turns ratio. The impedance is proportional to turns ratio squared, so 9:1 :) .

[@lmachielse7077]

Hi Peter, Thanks for this video, ik made for the first time this 9:1. I ll have one question how to connect to the connectors? Can you send me a picture please? 73 PD2LM

[@chickenhawknwc]

I have notice that the coax shield wire where you soldered to the balun is long does this matter? You had said that this connection should be as short as possible. Thank you for the great video.

[@TRXLab]

It will matter a bit but for this test configuration it is fine but for the final product it would be unacceptable. Thanks for watching 73

[@samuellourenco1050]

Hi, Is it there any advantage to use a 26 mix (yellow/white) iron powder core for low frequency? Many people don't advise such materials, but I was successful in doing a working UnUn out of this stuff for the AM band (just as an experiment, and I didn't knew any better). And, although it is efficient, it starts to die at 4MHz.

[@jonfortier3664]

a little sand paper action works well to remove the di electric insulation off of the transformer wire ... also why not use pvc coated / jacketed wire ? ?

[@dennisbauer3315]

Couple years late, and been out of it, Could any one please point the schematic for this 9:1 un un I do not find it in video?? Thank you in Advance

[@kadicha117]

Other sources show the three windings starting under and finishing over (or vice versa). You show two over and one under. Does that mean one winding is reverse phased relative to the other two. Yours obviously works properly; am I missing something?

[@dinosworkshop6870]

Super fantastic tutorial video. I been waiting on this one. Quite a value for a top notch balun. Great work and much thanks. A big thumbs up !

[@TRXLab]

Thanks you, glad that you like it 73

[@andrejstefanovski]

Thank you for this series - it is beyond excellent. Is there any detriment to using solid 14awg (~1.62mm) transistor wire for the 1:1 attenuator or the 4:1 transformer? I will be building 3x 1:1 attenuator, 1x 4:1 transformer, and 1x 9:1 transformer. If there is no negative effect, I would prefer to use the same wire for each component and am too inexperienced to identify a negative from using 14awg solid for the previous builds.

[@TimHavens]

I built this from your video and it works PERFECTLY. Thank you for such good direction! 73 de WW1L

[@_PJB_]

Great video but I'm confused, there are only 8 turns?

[@geirha75]

sometimes they use 9 windings with 9:1 unun does it matter ? 8 or 9 windings?

[@TRXLab]

It's all about finding the right balance between saturating the core material and having enough inductance

[@theepatriot5322]

FT240?? What mix? Is the 9:1 voltage or current? Unun?

[@redjohn20001]

I loved the Balun video series Peter, how about a 1:64 EFHW HF antenna Balun?

[@TRXLab]

Thank you John. 73

[@MrLittlmike22]

@@TRXLab yes please! 1:49 and 1:64!!

[@afonkin08]

Hello, will this balun fit long wire antenna?

[@TRXLab]

no not this one