Clearing Up Some Confusion About End-Fed Wire Antennas.

Hoping to clear up some confusion on end-fed wires, half-wave or random and the impedance transformers used with them. You also get a free rant on contests and a quick glimpse of my new Elecraft K1. Check out the Half-Wave End-Fed antenna group on Facebook, by Steve Ellington. Formulas for half-wave wire calculations are 143/f in MHz for meters and 468/f for feet. Feedback would be appreciated especially to correct any mistakes I may have made in my analysis. Version Française en cours d'édition...
EARCHI 9:1 UNUN:
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Random Wire Antenna Lengths:
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[@jeff-73]

Every 5 seconds of this video you cleared something up that was confusing me and no one else could explain it for my grey matter to digest. You are an amazing teacher and your presentation and instructional aids were amazing. Thank you so so much for this.

[@RadioPrepper]

Thank you :-)

[@cw2gtc]

Agreed. Very professional, yet personable to listen to. (😉disclaimer… My mom was a US military wife, originally from Luxembourg. So, the dialect is most pleasing to my ear).

[@Justin-bd2dg]

I built a 3 core version 64:1 and then I tapped the coils at the 49:1 point and ran a seperate wing nut. So now I have 2 transformers in one, a 64:1 and and 49:1, it works great! Thanks for the video!

[@RadioPrepper]

Good idea!

[@AdamosDad]

I hate contesting, its so rude for a guy that wants to rag chew to get pushed out by the "all important contest" Great informative how to video, thanks Gill 🎙73's kd9oam

[@Pelnied]

I hate rag chewers, it's so rude for a guy that wants to contest to have a frequency taken up because it's the rag chewer's special frequency that he uses every day to listen to himself talk for hours on end. He's already talked enough, let someone else talk! Share the band and don't hog frequencies, whatever you are doing!

[@georgebodley8068]

@@brad1367 try giving other operators some room on the bands instead of hogging the whole band width be like the RSGB contesters operate within a certain band width which gives other users the opportunity to use the bands don't be selfish.

[@georgebodley8068]

@@Pelnied you might hate rag chewers but dont be selfish and hog the whole bandwidth make room for all users Remember Amateur Radio is a broad church .

[@99jcarter]

​@@Pelnied9o

[@noimnotarobotcanubeleiveit7024]

Im no rag chewer but i like to have a chat for up to t minutes before moving on. Shouting numbers is boring. I often end up pushed on the warc bands when propagation is poor over 20m. All bands should have a warc section where contests are invalid for points. And we dont need 4 channels for ft8 warbles.

[@AllFouRoux]

This should be mandatory viewing for Hams; so much great information packed in this video.

[@davidwilcox9110]

The last half of this video is the most important and a very good explanation. I have been a ham for 62 years and this is the best explanation I have seen. Dave K8WPE

[@dougtaylor7724]

Something about the presentation helped me to finally understand 1/2 waves and their transformers. Many thanks, enjoyed your video.

[@TheHarpanOnly]

Yep, I feel same.

[@adriansalt4521]

I just had to say thank you so so much for what I've found to be the best explanation to End Feds, Random Wires and Dipoles on the internet. You have allowed me to understand such fundamental principles of resonance in a wire, why feedlines don't radiate EM energy and allowed me such a fantastic and solid grasp on the basics of EM radiation in a wire. I also have to thank you for your superb explanation on UNUNs and why and in what cases they would be needed. I really cannot thank you enough. Just had to tell you! Adrian, M0AAG.

[@RadioPrepper]

Glad it helped :-)

[@dancingbear6239]

Thank you! Your explanation of current flow in a HW was excellent. I now understand why radials are not needed for a HW but are needed for 1/4 wave. Non technical but spot on.

[@JulietNovember9]

I scoured youtube and google to understand transformers and this is THE best explanation ever. Very clearly done. Thank you!

[@simonbates8735]

I go to the 30M band. Regarding end-fed antenna I use a W3EDP (25.6M) which seems effective across all amateur bands. Love your regular KZbin videos. Thank you.

[@metalfabman5477]

This is the best video I have ever seen that really explains in layman's terms the whole end fed, half wave antenna thing using ununs or baluns. You have finally explained all of this so that even an old retired welder like myself who just enjoys making antennas and trying different things to get on the air can understand how it all works, even without an electrical engineering degree!! Thanks so much for taking the time to make this wonderful video!😃

[@RadioPrepper]

Glad it was helpful!

[@StevePotter-G6HOQ]

Whenever I see any hams asking about end fed antennas and how to go about making one I always point them to this video, so easy to understand, and even if licenced 30+ years you can always learn something new.

[@RadioPrepper]

Great thanks!

[@larrywieberdink8379]

This is the Best!! explanation I have ever heard comparing 1/2 wave and random length antennas and the need for size appropriate transformers. Excellent job!!

[@JDS11ify]

Very clear explanation of ununs and the cause and effect of the windings. Will listen in more!!

[@rjinnh3933]

Very good compitition of Half vs Random length antennae. Thanks. And 30+ minutes is not too long on a technical subject like this. Keep up your good work. We appreciate what you do......

[@RadioPrepper]

Thank you!

[@Steve_Wardley_G6JEF]

Gil, what a brilliant explanation of wire antennas and UnUn's. You've cleared up a lot of confusion for me on this subject. Thank you.

[@spudmurf9323]

For me also A1!

[@eddy2561]

Absolutely the best explanation 49:1 vs 9:1 out there! Merci beaucoup. ~ k6sdw

[@thirtycrows]

Brilliant. Can't tell you how often I've watched this video. Built one for 30m yesterday and it worked extremely well.

[@RadioPrepper]

Glad it helped 😀

[@frastephen]

This is the best explanation of the theory behind an EFHW antenna that I have seen ... Well done! And, very helpful!

[@nochems]

Great video. Easy to understand information for someone beginning to learn about HF antenna building.

[@DennisMathias]

This was quite entertaining! I agree. Contests are agrivating.

[@jay-rus4437]

Agree with you on contesting. Glad that there are so many options and variations of amateur radio. However, we are taught as a general rule to show curtesy to others, but this seems to be put aside during contesting. There should honestly be some band plans put together for temporary areas to be used for contesting. 73 K5JRX

[@cthoadmin7458]

Excellent info! Thanks Gil. Tried the 0.05 wavelength, as you said it had no effect. Stacked 3 ft240 -43 together for a high power efhw and it handles 400w with no problem. Steve Ellington’s channel is good for this.

[@RadioPrepper]

Great, thanks for reporting :-)

[@noelbulls8628]

To calculate the 1/8th wavelength do this example: 468/frequency =1/2 wavelength x2 then multiply it by 0.05 this will give you the length of counterpoise. Cheers

[@darrinpearce9780]

I've always run 0.05WL and never had RF coming back at me. Great antenna for portable/QRP. Thanks for the excellent information and explanation. Toroid material is always a mystery ;) 73's and fair winds.

[@Wyowanderer]

GREAT video, Gil. There's more information in this ONE video than I've been able to glean in the last couple years. Thanks again, friend.

[@Aussat]

Great video, I have been wanting to make my own for some time now but was confusing, your presentation has made it crystal clear. Thank you very much. 73 Glenn ZL1MY

[@Dennisjp-8318]

Great job at explaining everything on end-fed, random wire, and un un, I got a lot out of this thanks Gil.

[@G4KDXlive]

Agree with your comments on contests. I've heard them say " everybody enjoys contests " - inability to see the hobby from anyone else's perspective.

[@theunconventionaldeal3879]

Contests are a big spam challenge, what's worse is they will spam right on top of you after asking "is any station on this freq" instead of waiting for a response they crap all over your qso.

[@jamesk0ua]

Contest's are a great way to work DX entities that you need and If working for WAS, I can think of no better way to quickly work many states.

[@ReverendBow]

Couldn't agree more... contests are a waste of frequency spectrum... I love it when you hear someone have to repeat his callsulign 5 times, then the get a "5-9" report...

[@StreakyP]

three simple rules to add to all contests to make them more acceptable to all (whilst not detracting from the contest);- a) only use "even 10's of freq" for the contest... ie 0-10 yes, 10-20 no, 20-30 yes, 30-40 no... 200-210 yes etc etc. b) if you have "big boots" you cannot monopolise a single freq and just "claim it" to the detriment of all others (including other contesters)... implemented by you cannot be on any one frequency for more than 10 minutes... you must move after that time and find a free space yourself. If your log times show excessive single freq use then points after 10 mins will not count. If you repeatedly stomp on smaller stations to make your space you will be deducted points. c) With the easy availability of waterfall displays these days, Splattering "wide boy" contestants will simply be disqualified.

[@KjartanAndersen]

Totally agree. I do not like contests. I like experimenting with antennas and get feedback on different setups on air. Contests are only hello-goodbye-next. Never understood the appeal of it my self. Leave some of the bands off limit for contests.

[@larrybarnette4795]

You can also tap a 9:1 midpoint at the junction, and have a 4:1 ratio, which may be a closers match on some bands....almost free.

[@markcarleton6647]

Thanks for the fantastic explanation of the difference between 1/2 wave and “random” wire antennas!

[@binder098]

Thank you, when I watch enough of these videos and especially with concise hands on experienced operators like yourself, it all slowly sinks in. Actually, I feel your misfortune with the contest turned out to be quite fortunate for this viewer and like a cat, you anded on your feet with this content substitution.

[@kelpfl]

Nice video! Thanks for covering this stuff. I can't tell you how many concepts you covered in this video that I have heard people discuss and never understood.

[@acestudioscouk-Ace-G0ACE]

Thanks so much for this. I'm returning to amateur radio after a 31 year break. The information you give here and in your other videos is really useful. Thank-you.

[@RadioPrepper]

Glad it helps :-)

[@peterfitzpatrick7032]

I imagine you are well rested... 🙄😂 😎👍☘🍺

[@gettingpast4391]

Best video ive ever seen regarding end fed wires and impedance match transformers... built a 49:1 for QRP immediately after watching this video and realizing i had some small type 43 cores in my box. works great.

[@RadioPrepper]

Awesome!

[@briantheminer]

I’ve learnt more from this video than any other antenna learning method!!! Great 👌

[@RadioPrepper]

Glad it was helpful!

[@joselima9398]

thanks for the great explanation, probably the most clear explantion i've come across and i defintely learned so much about how end fed antennas work.

[@mhinnebraska]

Thank you for the clear details. This helped me to understand concepts that were very murky before.

[@LarryAnnen]

I can’t thank you enough for your detailed explanation on how to make an un un.

[@RadioPrepper]

Glad it helped :-)

[@chrislewis954]

I agree with others here that you do a very clear and helpful description of the basics. A valuable resource - Thanks Gill

[@hobbiehobbs]

I always learn more when I view your videos. Thank you.

[@DucatiMTS1200]

Thank you for explaining the workings so clearly. Now I understand a lot more. You are an excellent teacher.

[@RadioPrepper]

Thanks, glad it helped!

[@nathanhouck2403]

I genrally agree with your comments about contests, but without seeing if anyone else has mentioned it, we do have 30m (at least stateside) as a playground during contests. Thank you for info on end fed antennas. Good info.

[@peterfitzpatrick7032]

Contests are a pain & your point about them taking up the whole band is exactly right... 🙄

[@thormusique]

Excellent, Gil, thanks! I heartily agree that the contesters shouldn't completely take over the bands. It's kind of ridiculous. Supposedly no radio amateur has priority over anyone else. However, that seems to go out the window during a contest. Anyway, very interesting information about end-fed antennas. I learned quite a bit!

[@SuperCanuck777]

A lot of contesters are a damn nuisance-a law unto themselves even swamping all the QRP HF freqencies!! this worlds gone mad

[@adammoss5284]

There are the so called “contest preferred” band segments which are an attempt to give everyone a bit of breathing space. However it is up to the contest organisers to make these segments an important part of the rules. 73

[@TheDgdimick]

You're explaining the exact way the American Field Days is each year, don't want to not "play", then suck it up and come back later. I feel your pain.

[@AndrewBryantPianoTuner]

Please keep making these videos you are an excellent teacher my friend and people love you..

[@RadioPrepper]

Thanks, will do :-)

[@videog7747]

New ham here. Thank you for this. You are really great at explaining things!

[@usernamemykel]

WOW! What a fantastic teacher! Just one little thing - "Impedance" is pronounced "Im-PEE-dance". Many thanks for such a clear and informative explanation.

[@RadioPrepper]

Noted thanks!

[@kengerace]

I just happened to stumble on your video through a suggestion from you tube. Well done sir. Very well presented. Thank you. I’m going to checkout more of your work.

[@michaelclutton8446]

Have just subscribed, agree with you totally about contests after 50 years in the hobby still think it’s just an ego trip for a lot of people

[@dangruner5926]

I like this guy. Feels exactly the same way about "contests" as I do! ;)

[@Roger_Stenning]

Well said, indeed :D 73 de G1LIW

[@RadioPrepper]

That's because they only know how to sent five numbers: 599 73.

[@TXLorenzo]

Contests are another form of radio jamming. They are my que to play on FT8.

[@henbentoify]

Thank you for your time. Best presentation I’ve ever seen on aerial transformers. 73

[@clivedavies3]

I am a swl and I know what you are saying the power output from some stations obliterate a wide bandwidth and only they ask for certain contacts which defeats the object of collecting contact from anywhere and dx and ruins the ham radio for new licenced hams.

[@kiweekeith]

Thanks a Stack.... Greetings from New Zealand ..... What an Absolutely Brilliant vidclip .... So 'Simply' and well explained vidclip ....Very best to All from ChCh, NZ

[@tonypoloney8721]

Wow! what a great presentation. I will have to watch several times for this very interesting information to sink in. Really enjoy your videos. Thank you so much.

[@trbowlin]

Great video. I learned more in this video than in the last 5 or 6 I've watched. Thanks!

[@ernestb.2377]

Well Sir you did a very good job explaining some important basic working principles. Very glad I have watched it. Thank you!

[@W-733_KWX]

Excellente explication Gil sur le sujet. Some explanations in English now for the non French speaking amateurs to understand: Cap is supposed to help on higher bands and raise resonance frequency as far as I remember well :) Also as far as I remember well, material #52 is good for the lower bands and higher power (ex. 3 stacked 240-52 for 1/2 kW with still good efficiency ratio) and 43 will go up to 10m but with the cap to have a more centered resonance frequency. Also, on 6m, I would advise either use a 2 meter 5/8 antenna which happens to be electrically 1/4 wave on 6m or a telescopic antenna with some counterpoise, so depending on the available supports.

[@RadioPrepper]

Thanks. I do have the same video in English..

[@timelord1137]

50ohm - 😍 65ohm -😏 400ohm - 😢 1000 Ohm - 😭 4000 ohm -🤬 Make your radio happy - match the impedance)

[@daveryan2148]

Great video! Wish this straight forward information was around when I was first learning this... I had to descramble wives tales from old guys and experiment.

[@vjdav6872]

I agree 100% with you my friend. I was a QRP for years in India and then in US about 40 years ago. Well, NOW i am back after other life things! And very surprised - shockingly to what you said is so true. Oh well I still plan to get back in 4-5 months.. 73 ...ex vu2du/w3

[@PatFortino]

Thanks for the detailed explanation of 1/2 wave wires and end feed antennas.

[@Pelnied]

It's up to the amateur operators to police themselves and to be mindful of their actions. People should think about what they are doing and if they are stepping on someone else. It's not the job of the contest organizers to control every aspect of how to play radio and babysit each one of the contesters. The lids out there are going to cause problems regardless of the rules set in the contest. Sometimes the band is too full to hide in the lower section of the band. Sometimes you only have an antenna that is tuned to one section of the band so you transmit where you can. Sometimes people don't have an Extra license and can't use the Extra portion for CW. CW is able to be used across all amateur frequencies and it should remain that way. Don't try and limit where CW can be used, it's already a dying art that new hams don't care about. Don't get mad at contests, re-educate the disrespectful or oblivious operators.

[@Inkling777]

You make a good point. Sometimes the WARC bands, 30, 17, and 12 meter bands, are not open. Contest organizers could set aside 50 KHz of the CW and voice bands they use and make them off-limits to contest activity. That would leave a little space for everyone else.

[@robertlundstrom8061]

I also have a K1 that I built. This video is terrific! One of the very best antenna instructional videos. I can't wait to build my 64:1 unun! Thanks for the info. - W9PZ

[@RadioPrepper]

Let me know how it works for you!

[@Mil1806]

So well explained! EFHW seems so easy but they have their peculiarities. I have a core ready for making one for my qth, this video will help me a lot! Thanks for your videos!

[@alexeizhiltsov6797]

Gil, this is an amazing and very helpful video. Thank you so much. And it does not matter whether your explanations are correct from the point of view of high physics, with all those formulas and reactivities, as some people tend to say in the comments: the important thing is your advice works in practice and helps those who do not have time to read specialized books on how to engineer Space Shuttle antennas - we want something simply in our backyards. To me the simplicity of your explanation is the primary advantage - it is easy to remember what to do and how to do, and results are effective in real life. Also thanks for the links to those antenna shops - I never knew they even existed, being limited to MFJ, Diamond and similar huge companies. Do make more of your wonderful films if you can - this is very helpful for the HAM Radio community. They inspire to experiment, to fo to the fields and develop the hobby skills, thus developing the whole hobby. Everyone can go and pick those professional books on antennas - I have dozens of them, but get lost after 10 minutes. So, I prefer your films than professional books, mostly meant for professionals in celular and commercial communications. 73 de R2ARM!

[@RadioPrepper]

Thank you. My goal was primarily to make it understandable...

[@dogtowndrums]

Thanks for this video. This is the first time that I feel that I've actually understood this subject. 73

[@gblan]

Some activités in life have no business being a competition. Talking on a radio is one of them. I guess some/a lot/most people in the amateur radio community do not realize how stupid it actually is.

[@joshuacalbick4834]

Thanks for this video. Cleared a lot of confusion up and simplified a lot of things for me. Kinda that lightbulb moment. Seeing it drawn out made it understandable. KJ7OEP

[@RadioPrepper]

Glad it helped :-)

[@peterdekeles.]

Thank you. I now understand unun and 49:1 vs 9:1. great information

[@RadioPrepper]

Super!

[@ziyayergok6090]

one of the best explenation ı have ever seen...perfect....super...thank you Gil...

[@DEplinker]

Big fan of you and the work that you do... your videos are excellent. You are to amateur radio what Milton Friedman was to economics... having a solid foundation of knowledge, you're able to communicate that knowledge in a very easy to understand method.

[@RadioPrepper]

Thank you!

[@LaurentEgliAdventure]

There is one thing I don't quite agree with in your 1st schematic. At the end of the antenna by definition the current should be zero, the missing current should be graphed at the other end (near the feed input).

[@sircompo]

I'm just starting out and this video has been more enlightening than anything else I've found so far. Thanks Gil 👍

[@RadioPrepper]

Glad it helped!

[@johnwest7993]

No need to complain to us. Send a link to this video to contest organizers, and point out that your video has over one hundred and fifty thousand views.

[@pincus321]

Thank you for explaining this. I now understand more.

[@davidcarroll6020]

Excellent training and information that is very usable, thank you

[@joecraft4409]

Explained so well even this boy from Texas USA can understand. Fantastic job Gil!

[@RadioPrepper]

Glad it helped!

[@Angrath]

Contests are awful. If you only have time to play radio on weekends like I do it really puts a dampener on the hobby. I get pretty sick of it. This was a super helpful video and clearly explained the diffrerences between randoms and half waves. I'll watch it again I imagine! Thanks.

[@RadioPrepper]

Thank you :-)

[@dennisbauer3315]

This bloke and TRX Bench are top blokes, I love the way they pronounce balun, love it. and yes contest, what is it that makes them the Lords of Amateur Radio, is it a power trip, some times I think so.

[@rl4795]

THIS WAS....BY FAR.... the best visual explanation of this topic. THANK YOU so much, Sir. KF4UTF/HZ1 - Robert

[@RadioPrepper]

Thanks!

[@billhartig4805]

Extremely well explained. Thanks.

[@w4mkh]

Well said sir. I have nothing against the idea of contests but I hate how the contesters just take over all the frequencies with no thought to sharing the spectrum with other hams.

[@davidvelen9835]

Agreed, contesting is waste of time in my opinion.

[@MoTown44240]

Thanks Gil. I watched this several times and got more from each viewing. :)

[@TheArtofEngineering]

End fed QRP antennas are fun to build. Buy them if you have the $$$$ but building and experimenting with them is A LOT OF FUN!!!!! The comps are keeping CW alive and making the bands busy.....but I do concur on better organising of the bands as "the bands are there to share!" :)

[@K3RRR]

Very nicely done, Gil...worth every minute since I have been using these kinds of antennas for years...I am with you, my 135' EFHW myantennas 80-10 works far better than my 9:1 unun 175' and 124'. 73 de Robert K3RRR

[@RadioPrepper]

Yep, thank you for retweeting!

[@Chungustav]

I hear ya. I'm into emcomm, nets and talking about radio, not contests.

[@SNAFU_73]

I agree on the contesting...that's why I prefer to stick to 17 meters when the contests are going on

[@dr.tomgio6694]

Gil, this is an excellent instruction video! Thank you for your efforts. Tom IK7YCJ

[@danielsteele7544]

Excellent teaching Thankyou

[@DrHWO]

Fantastic presentation Gil ! This has provided the clarity I needed to grasp the general principles of feeding random vs half wavelength antennae and the benefits and disadvantages of each. A whole new world of experimentation has opened up! Thank you. 73, 2E0HWO

[@MaxWalker1]

Thank you! I am beginning to understand now.

[@brianbrown4965]

Ham radio to me is communication between other ham radio users , and like you i do not compete . To me contests are not personal and its not in my book to compete . i love it when i contact other users and have general chat about there family weather location where they live . to me this is so good. at my local club its contesting so i dont do it and they ask why and i tell them. I did sell all my hf radio gear for this reason because all that came on was contests any other time nothing on . not ham radio to me . i totaly agree with you . thanks for the video .

[@RadioPrepper]

I couldn't agree more...

[@jackernissee2372]

Thanks for this great video - Explains a lot. The best I’ve seen so far.

[@jay-rus4437]

Agreed. Im new to ham, but have quickly learned that ham “should” be about consideration and respect for other operators. They are looking past that by believing that everyone should see ham as they do. Personally, Im not currently interested in anything other than VHF and UHF radio operations. Both simplex and repeater use. My wife and son will be taking their tech exam in 2 weeks. Nice to have the family involved for both mobile daily use, but also educated emergency operations. i say educated because there seems to be some sort of strange trend in “preppers” buying cheap radios, no license, and then believing that they will be able to operate those radios under emergency conditions. I doubt it. At least for most anyway. So many of them will not have the understanding of radio communications, repeater connections (assuming they are still up), radio protocol for net use. These preppers will be slapped into reality when they need their radios the most and realize it doesnt operate like a walkie talkie from some big box store.

[@techiefan1986]

I believe the capacitor is to cancel out stray inductance for better matching on the high bands.

[@rodchisholm4790]

Thanks Mr Radio Prepper. Very useful information & education. Comprehensive, comprehensible and entertaining. I am learing so much from you. Merci Beaucoup vraiment!

[@RadioPrepper]

Glad it helped:-)

[@TridentMissileTech]

Totally agree with you about contests.

[@AzPauly]

best antenna lecture I have ever seen, thank you.

[@RadioPrepper]

Thank you 😊