EFHW MULTIBAND ANTENNA with 49:1 UnUn home made (PART1)
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- Опубліковано 15 жов 2020
- I've try to made my multiband experimental version of the Multiband EFHW antenna without traps which will not work only on primary band, on it's harmonics, but also on WARC bands.
In this first part I want show you complete process of made this antenna. In the next, second part I would like to test this antenna in the real outdoor conditions and do measurements with my antenna analyzer Mini1300 and possibly make some QSO's.
I hope you will enjoy this video. If you like my videos, please don't forget subscribe to my channel ;-)
73, Paul.
- Link to my website: om0et.com/efhw-49-1-unun.html
- Very informative PDF presentation from Steve Dick, K1RF: gnarc.org/wp-content/uploads/T...
- Very informative website about the EFHW Antennas: owenduffy.net/blog/?s=Efhw+tr...
- Dan Koellen AI6XG website here: www.ai6xg.com/post/efhw-xfrmr...
- Download my EFHW Antenna Calculator: om0et.com/files/OM0ET-EFHW-Ant... (OpenOffice recommended)
- AMIDON Toroid FT240-31 Specification: ferrite-shop.com/product/ft24...
- AMIDON Toroid FT240-43 Specification: ferrite-shop.com/product/ft24...
NOTE: In the EFHW Antenna Calculator were used two different formulas for metre and for feet lenghts. Therefore direct conversion between them doesn't match and they slightly differ. It's due to my experimental research, until I will find which one will be closer to reality during my next tests. To open the Calculator we recommend use the free OpenOffice software
#EFHWmultibandAntenna #HomeMade #OM0ET - Наука та технологія
Veliký respekt a dík za Tvá poučná a vzdělávací videa. Tolik jsem se z nich naučil a postoupil o hodný kus cesty dopředu. Tolikrát mi pomohly v úsilí o oživení a poslech starých vojenských radiostanic. Velmi si vážím Tvé práce a toho, co děláš pro nás, které to zajímá. Zdravím z Čech, z lesů od Rakovníka.
Jiří ďakujem za Tvoju podporu a sledovanie videí! 🙂 Som rád ak tie videá niekomu pomôžu! 👋😉 73, Paľo.
Nice job! A 49:1 UnUn is very costly so, making one yourself saves money. Looking forward to see how the SWR looks on each band. Thanks for posting this video...73!
I made 49.1 couple weeks in 133 feet long and I've ground it with earth rod the SWR is very good it below 1.5 on all 4 bands 80 / 40 / 20 / 10 meters it excellent antenna am planing to add 1 to 1 balun soon.
I repeated your design! I did it! Only I wound the transformer on a square ring from the high-voltage transformer of an old kinescope TV, or rather from two П-shaped half-rings glued together. The length of the antenna turned out to be 38.7 meters. SWR at bands of 80-10 meters
Congratulations for a good job! 👏😉 Best 73! Paul
Very interesting Paul. Good job !
Thank you my friend! ;) 73
Sir, you are on a new level of professionalism and creativity! I am thoroughly impressed at your attention to detail. Watching this video was very mesmerizing. I have trouble paying attention to things, but you explained this very well. Thank you! Joshua KC3SIS/AE in North-East Pennsylvania, USA
Oh, I love your callsign btw. ;) RARE and otherworldly.
Thank you Joshua for your kindness and the nice comment! It's my pleasure you like my videos 😊 Best 73 from Slovakia! Paul
Paul, it is a marvelous video! You are incredibly deft at fabricating your container box. (I cannot ever get the drilling so clean nor the SO-239 socket aligned!) I would only add that, when cutting the hook eye bolts, if you screw a nut on them first and then cut the bolts, when you unscrew the nuts it will re-thread the bolt eliminating any rough or damaged threading.
It's trivial perhaps, but a trick I learned a long time ago.
72/3 de k6whp
dit dit
Thank you for an advice and for your very nice comment! :) Best 73! Paul
The applicability of your project is simple and excellent thank you. TA5LVC, Turkey
Thank you! ;) 73 de Paul
Thanks for the updated film, it helped me greatly as I intend to use 1/2 at 80 in one run feed it to my home made 49:1 unun, and with luck I might even hook it to mAT 180 AUTO TUNER, as at he minute I use a COBRA Doublet hooked to kw eze match as my primary hf. keep up with the info on your channel very useful.
Regards
Derek G1GDB
Dry well presented OM.
Subscribed.
Fantastic project 7351.
tres interaissant tres bonne vidéo merci beaucoup
Parabéns amigo pela antena muito boa antena
Enjoyed the video, Paul...looking forward to Part 2. Thank you and 73! de WX0V
Thank you Scott ;-) 73! Paul.
Outstanding video.
Milý Paul, ďakujem za video 73 de 4Z5UY
Well done. Good video. Thanks!
Thank for informated about Multiband HF Antenn
I’m struggling with understanding how to measure the length of each band “segment” - do you measure the wire flat and strait, then ignore any slack introduced by the terminal blocks band insulators? Or do you measure the length from the point where it exits a given
Isolator and enters the next one?
Very nice build.
Thank you! 🙂👍
Hi, very glad I came across your video on this transformer, together with some other web info I have made a QRO version with 3 toroids and up to 400w it works fine, theoretically it should be good to 1kw on SSB.....if only :-) thanks Paul, from Paul GM0EDJ
Thanks for your videos 👍👍👍
Great video Paul de N9NY
I think I would have put the wire into the connector before installing it onto the back of the SO 239 plug though.
7351 du bon travaille super vidéo👍
Very good. Thanks
Thanks a lot Paul for the video and experimetnal antenna. Great ! - Miguel - EA4LW - 73´S
Thank you for watching this video Miguel! 😉👍
Hello Paul. I recently purchased an end fed antenna from Ebay. I want to use it mainly for 40 meters. The antenna length is 41 feet., so this is roughly a quarter wave on the 40 meter band.
If this antenna length was around 66 feet instead, this would make it a half wave at 40. Would the performance be much better then ?
Paul Great video you numero uno thanks 73 from kb2uew
Hello Paul , Greetings from belgium 73 Albert . vidéo very nice thanks. 👍👍
Hello Albert! :) Thank you for watching ad greetings from Slovakia! 73, Paul :)
Many thanks
Excellent!!!
Thank you 😃
Hi
Can you throw light on why my 49:1 box resonates on 40 M with 12ft more wire than calculated 468/7 = 66ft Half Wave ~ but actually needed 79ft !!
well done!
One tip for twisting bi-filar copper wires:
Fold it double. Chuck a small 'hook' (like those for hanging small things to a wall) in an electric screwdriver / drill and hook the folded end of the wire. Clamp the other end in your small vice. Run drill slowly until you get the desired twist-density. The 'hook-method' is suitable if you're going to make many transformers with bi-filar windings. For just one winding, chucking the wire directly is almost as easy and might be quicker.
This method will create a very even twist and straight bi-filar wire which is both esthetically pleasing to the eye and very easy to wind tightly on a toroid! I 'invented' it when doing some drone-related electronics (telemetry) in 2009. 🤓
Thank you Michael for very nifty tip ;) I will try it in my next antenna project. :) 73, Paul.
Very good
👏🏻👏🏻👏🏻
buenos días. saludos desde Colombia. hk8rkf Javier. ya tengo consgruida la antena y el balum 49: 1. Necesito saber cual debe ser la longitud de cable que hace de tierra (contrapeso) o hay necesidad de conectar un cable conectado a una varilla coopewell a tierra. gracias por la orietacion. 73.
You get the best wire twist by using a battery cordless drill on one end (locked in the chuck) and hold pliers firmly at the other end after measuring the required length. Switch it on low speed and done!
Some people recommend to put some Teflon tape on the toroid before twisting the wire unto. It protects the wire while wrapping process.
Very neat and tidy build, one question though: what is the purpose of the earth connection on an antenna I'm led to believe doesn't require a counterpoise? sorry if this is a basic question.
Grounding is always just the positive thing 😉👍
Great Video! I love how so many people are saying “why did you” or you “shouldn’t have”. Experimenting with antennas is at the core of ham radio. Just because others do it one way, doesn’t mean you can’t to it another. What glue are you using to attach the toroid to the box? Thanks for all your hard work! 73
Thanks Chris for your support! ;) Yes, my words ;) This is the super strong glue Mamut: www.denbraven.sk/produkt/mamut-glue-high-tack/ Very good glue for similar purposes. Thanks for watching and Happy new year 2021! 73, Paul OM0ET
Good job SV2YJ 73s
Thanks Panos! Thanks for watching! ;) 73, Paul.
Can you explain why you twisted the wires together for the first 2 turns? Also what is the capacitor for, does it do some tuning and if so, would a variable cap be better?
The 2 turns of twisted wire is the primer. This way it is simpler than using a single wire with lenghtening the wire by soldering (a joint) to continue with the secondary windings. Variable cap is not necessary, because this winding on this core needs exactly the named cap. ...you need a high voltage one. (the high impedance at the feed-point means low current but high voltage at the same time) Though on the 50 ohm end of the unun you have moderate voltage- but the capacitor handles high RF currents.
The extra capacitance makes it possible to have low SWR on all the tuned bands, even at the upper end. (maintaning the linearity by handling the primer leakage at the higher frequencies)
When I saw your call sign I thought "Alien Meditation" (or Mediator)! OM is used in meditation as a mantra consisting of the sound ˈōm and used in contemplation of ultimate reality. And of course ET was the alien from the movie of the same name... Don't worry my call sign is N3PLA, when I first got the call sign 30+ years ago people said PLA was Papa's Little Amateur.
:D :D Great! It was funny :) But yes I like the sci-fi movies and the best is StarTrek. That's why I choosed the OM0ET callsign :) Extra Terrestrial hi hi... I think one the most shorter callsign in the world in CW :D 73, Paul
Very cool....I'll have to make a few of these, I have a box of biscuit joints left over from a house building project. I wonder how many antenna's I can get out of 5,000 leftover biscuits.....
Lol, I quess it's around 1000 antennas 😄
I saw a lot of your videos and I'm very thankful for them, and please don't get me wrong, but "winding" is pronounced as wīndiNG, not winding (like the wind). 73s from Hungary.
Hey Paul, I was looking at the Antenna Calculator, Was wondering which band plan you are using,
I noticed that 6m band shows 50.0-52.0 MHz but 6m Band goes 50.0 to 54.0 and their are some other bands the same way.
Just wanted to know, I love the Calculator, And it will make things a lot easer, But I just wanted to know. Thanks For The Video.
73
I focused on the phone section of the bands. It was my interest 😊
Great !
Nice video but I do not understand why you are using different length of wires for each band, I thought that the EFHW antenna was resonant on the harmonic frequencies, so an 80m half-wave is resonant on 80, 40, 20, 15 and 10 using one wire length. not sure about 60, 30 and 17 though. oftentimes you do see reasonable SWR charts for some of these bands with the 80m half-wave wire. Now this system should work quite fine but it does a complicated structure to do it. The single wire presents the user a much simpler system to use. 73 Al ve3gam
Yeah me too now that I’m thinking about it ? I’m shurr He has his reasons!!
@kingjohnny3841 Please read also the video description, where is it explained 👍
Hello, Paul!
To tell the truth I don't undenstand a purpose of capacitor on input of of the balun. Could you please to explain.
Witam,jaką antenę polecasz do krajowych zawodów SSB pasmo 80m/40m/20m
Nie używam skrzynki.
Żeby nie było strat w odbiorze b.słabych stacji,czy lepiej mieć trzy anteny każda na osobne pasmo.
Czy bez balunu może być,trafo ma ponoć straty
Anteny jednopasmowe Rybakov/Bazuka czy dipol. jakie wybrać
mam przełącznik zewnętrzny na 5 anten,w domu mogę zdalnie zmieniać kolejnosc anten
za granicą mają linie zasilający kabel koncentryczny 40m 80m,żeby półfali było..
Skvelé video Paľo, Obsah tradične 100 bodov zo 100. Tento typ antény používam už 3. rok. Mám ju natiahnutú medzi dvoma bytovkami cca 35m nad zemou. Aj s 50 metrami koaxu chodí veľmi dobre. Pre tých, ktorí bývajú v bytovke na spodných poschodiach a nemôžu mať anténu a 600 ohmový zvod natiahnutý popred okná susedov môžem iba doporučiť. ............ Perfect as usual Paul. Content traditionally 100 points out of 100. This type of antenna I´m using 3rd year already. It is elevated between two block of flats about 35 meters above ground. With 50 meters of coaxial cable is performing very well. For those who live in an apartment building on the lower floors and can't have an antenna and 600 ohm lead in stretched in front of the neighbors' windows, I can only recommend it.
Ďakujem ze skvelé hodnotenie Ľubo! 😊👍 Som rád že aj ty mám dobrú skúsenosť! 😉
Paul, how much power can one of these take? Can it be built to take 200 watts? Sounds like the capacitor(s) would have to be very high KV rating and maybe larger wire size and dual cores? Terry
Somebody recommends 2kV, somebody 6kV, somebody 10kV. All these ratings are reliable. And it more reliable to 15-10 meters bands, maybe mostly for 10meters. But I had max SWR about 2-2,5 at 10meters, might be because of lack of caps, or maybe there is something with wire lenght
Big project
Great timing... I just bought a commercial 40/20/15/10 End fed!
Don't worry! :-) I still don't know if this antenna will really work. I have to test it first (part2). Weather here is wet and rainy, so I have to wait :) I wish you have many many nice QSO's with your new End Fed Antenna! 73, Paul.
Bravo
so 1 core for like 100 ~ 500Watts 2 for 1,000w? and 3 cores for legal limit?
Hi brother.
İ think this 49.1 transformer is seems like to eht transformer.Because the eht iş occure high voltage.And we use high voltage to one wire and the voltage walk to wire not weak.
Hello Paul, many thanks for this outstanding video. Just a question : what diameter do you use for the main wire ? 2.5 mm or 6 mm ? other ? copper ? Thanks a lot.
answer at 18:35
Very nice videos as always. Just thinking; what about a second PVC coated line, such as rotor cable with multi wires, so you can activate a relay on and off, so a relay on each connection, to remotely control the antenna for band selection, instead of lowering it to connect and disconnect. Just a taught.
Thanks! That is good idea Victor! But am worry that it would make this antenna very heavy and complicated ;) But somebody should try it because I am curious how it would work ;)
@@OM0ET Again, just a taught. Now, with this great video of yours, it seems to me as the entry point or fundament for such of an idea, it seems to me some vendor will come up with something close based on your great example. 73
I think, a trap antenna with its tuned filters at the segments does the same... - and the manual selection is not necessary. Lenght is selected by the frequency we use.
As usual, I'm enjoying this video of yours, even without any nature shots from your surroundings. One question though after seeing half of it:
Why are you cutting your antenna wire making it a 'linked' EF? With a correctly wound 49:1 or 64:1 impedance transformer - with a suitable core toroid, your EFHW should be resonant on 80, 40, 30, 20, 17, 15, 12 and 10 meters - in theory.. Right? What am I missing here? 🤔 Maybe I should watch the whole thing before asking stupid questions but then I might get the answer - or forget the question. 😅
The idea was to create an EFHW antenna tuned exactly for desired band (not use harmonics) and availability of WARC bands too. Therefore I cutted the wire on many shorter elements :) That's why is that my experimental antenna project ;)
@@OM0ET Aha! That explains it and makes sense! For a little while I thought that I had seriously misunderstood the concept of harmonics and the 49:1 transformer with the EFHW. 😁 Good luck and I'm looking forward to the field test. I'm expecting better results than from a random wire EF. 73 from Arctic Norway 🇳🇴
@@michaelfuchs1467 Thanks Michael! I hope that this antenna will work 😉👍
@@OM0ET Came to think about it: In Sweden we actually had a similar antenna with our military HF radio 'Ra195' (That's a modified PRC104) which is still in use by some Swedish special forces units (LRRP patrols made up by pararangers and combat divers - I used to be one of the latter).
This antenna used the same idea and was marked on resonant lengths but we just coiled up what was 'left over' to get it in resonance without using harmonics. It probably used a similar transformer (49:1 or 64:1) but I'm not sure.
The military frequencies aren't necessarily on harmonics anyway like 'HAM' -bands... I remember this wire antenna working extremely well and it was super simple to deploy - in contrast to the 'high antenna' which was a tall, sectioned mast with dipole rod elements. Usually deployed while grouped and usually not complete when you needed it. The wire antenna was stored in a small canvas bag accompanying the transceiver. I actually owned one of these radios but it was stolen from my TGB13 (Volvo 6-wheel military offroad truck) a few years ago. 😢
Most of the cutting and plugging is definitely unneccessary. Connect the Endfed Halfwave wire to the 1:49 impedance transformer and it will work on any other frequency which is close enough to a full number multiple of the original design frequency. On all these frequencies the feed point will show the approximately same (high) impedance. That means, you can operate nearly all ham-frequencies without cutting the antenna wire and with good vswr. I (and many other hams) tried it, it works. Only for non-full-number multiples of the base frequency it makes sense to put cuts and plugs into the wire, if you want to make the wire voltage-fed on those frequencies too.
Yes, but doing it this way, as he did, each band is an actual half wave length of wire by it self. Which is handy for those higher bands, like 11 meters CB. Which will also prove to be handy when he fine tunes each length for the lowest SWR reading as he goes to minimize the SWR for each section of wire with out changing any of the shorter set lengths of wire as each section is tuned in turn. This gentleman is a true crafts man who thinks ahead. In this, he doesn't use the harmonics, as each wire section is an actual half wave antenna as they are added by the splices. We would choose to use the harmonics, in a more portable or temporary SOTA set up and then deal with any off center issues with our radios. 80 meters tends to get a bit off when doing it that way. And a shorter version like a 40 meter antenna, would tend to loose some of those higher harmonics, like the 30 meter band and a few others so those would not be as low an SWR as this method. .
Next year I will make a set of linked wires!
Why did you select type 31 material? Most EFHW designs seem to make HF broadband transformer from type 43 material.
I have used this material because I didn't had the 43 material at this time. I hope I will use 43 in my next antenna projects. This is my first experimental EFHW antenna project so I have used parts which I had available ;) 73, Paul.
I believe type 43 is lossy and type 52 should be used instead, I'm no expert but here's a link to a good PDF from K1RF
gnarc.org/wp-content/uploads/The-End-Fed-Half-Wave-Antenna.pdf
Type 31 will probably cause a lot of power loss.
is it not mutilband without all the clips? from all ive read and seen you just need a loading coil for the 80m part
Please read also video description
My EFHW acts like it is shorted. No noise on receive and high SWR. When I unscrew the shield from the pl259 and only the center is hooked to the so239 I get receive noise. What would cause this? Thanks for this great video!
Maybe poor soldering? Hmm I donno
@@OM0ET Bending the coax a certain way at the pl259 caused it to short.
Where did you get the plastic wire winding holder - the device upon which you wind the antenna wire?
never mind i watched the rest of the video
@@johnkitchens5174 it was bought in one of the shopping centers with tools, I think Hornbach or OBI 😉
I wonder how long the biscuit wafer isolators will hold up in the elements without protection like polyurethane. Maybe he lives in a dry climate. I hate taking down antennas for maintenance.
It's portable antenna, not for permanent installation.
To test only 10 meters of tape in your project, I have procured multi-stranded cable and cut it in 5.10 meters length. Using the FT240-43 toroid, I wrapped the winding properly as in your video. I made the connection to the baluna that I have completed the related procedures. When I measured the VWSR measurement with MFJ 259D model swr analyzer, I saw that you were high at 28.8 mhz, which you determined as the center frequency. The total length of the cable is 7.5 m. When I extended it around, but I saw that the swr value was as low as 1: 1.1, 1: 1.2 because I didn't use the cable in accordance with AWG 20 standards? cable length increased. Do you have an idea? Thank you. TA5LVC, 73.
Yes. Shortening coeficient vary on diameter of the wire. I use 1.5mm PVC coated flexible copper wire.
@@OM0ET Thanks for informations. 73
What formula have you used to calculate the lenght of wire (half wave)?
3:23 L(m)=150xA(0,98)/f(MHz) or L(ft)=468/f(MHz)
They will give different results :-(
@@geokuf9679 yes, exactly. That's why it is it my experimental project. I need to find which formula is closer to reality :)
Another question:
What's your reason for choosing a toroid of '31' -material? How does it compare to 43 and 52? Efficiency? Price? 🤔 (important factor for me). I was told by someone to stay away from 61-material due to too low permeability even though it has a high temp tolerance. I will probably go for a smaller toroid (or maybe two stacked) of 43 -material in my upcoming EFHW experiment since I use max 20W and expect the Curie temp of 130 degrees C to be well within demand from my QRP+ power levels)...
I have used this material because I didn't had the 43 material at this time. I hope I will use 43 in my next antenna projects. This is my first experimental EFHW antenna project so I have used parts which I had available ;) 73, Paul.
@@OM0ET I see. That's the problem I'm having too, finding the 'correct' material in 'usable' sizes - for a price that is tolerable to me. I'm also having great difficulty comparing materials between producers since 'all of them' (not really that many around) present their products with emphasis on different properties. For example, Ferroxcube doesn't present permeability while Amidon do, and vice versa. It's really hard to find suitable equivalent ferrites I think - not like finding equivalent transistors...
Have you found a good supplier for ferrite toroids in Europe, selling small quantities for R&D?
I'm usually trusting Elfa Distrelec as my component supplier. This is an old company, in existence since at least the early 1960's, HQ in Sweden and used to have the slogan "Everything between antenna and ground". They became my toy supplier very early! I remember browsing their FAT, bible-like catalog as a kid in the late 1970's, dreaming about NAGRA real-to-real tape recorders and insanely expensive computers. ELFA used to have EVERYTHING and was later the main supplier to the universities and R&D labs I've been working with, like ERICSSON, SAAB Missiles and Bofors in Sweden, but I'm feeling seriously let down by them lately when they're not stocking the toroids that I'm expecting to use. 😁 Ordering from the US is pretty much out of the question due to the insane shipping and handling fees, at least with suppliers that I've come across. Sometimes a seller on Amazon is offering shipping to Norway but that's very seldom. 73! 🇳🇴
@@michaelfuchs1467 FT-240-31 is far supirior to the FT-240-43 in Wideband transformer applications, FT-240-31 covers a greater bandwidth at lower frequencies from 1mhz to 300mhz the FT-240-43 only covers 5mhz to 400mhz.
The FT-240-31 is also a lot better for RFI suppression applications such as in 1:1 Common Mod Chokes compared to a FT-240-43
More info Here
FT-240-31 toroids.info/FT240-31.php
FT-240-43 toroids.info/FT240-43.php
@@Nathan1975Liggy Thank you for the input Nathan. Much appreciated!
I want my impedance transformers to perform well between 1.8 - 30 MHz with the main focus in the NVIS region so if 43-material isn't cooperative below 5 MHz this of course changes my priorities a great deal.
I'm primarily looking for small (50-size / ~13 mm dia) toroids now for an attempt on an 'ultra-slimline' transformer 'fused' with the antenna connector - to get rid of the traditional boxes on the antenna for a true 'bug-out' EMCOMM aerial as a gift for a very good friend's G1M. Therefore I'm thinking two 50-size toroids stacked and wound with perhaps 0.75 mm dia magnet wire, hopefully making it stand up to 20W 100% duty cycle transmission for up to 30 minutes at a time, so that I can use one with my G90 on full tilt too.☺️
I haven't done any fancy math on this, I'm just guesstimating. To be honest; the math and physics of toroids is far above my level anyway...
I'm not even convinced that we actually need toroids for our contraptions (but I have no reason to doubt it either). Why isn't a ferrite rod or 'binocular ferrite' for example, usable for an 'un-un' - or is it?? Any special physics going on in the donut shape? Maybe our sought after 43 and 31 materials aren't very common in other shapes? 🤔 Just curious here, not argumentative! 🤓
Also thank you for your input on CM chokes! I was just in the process of wasting some much needed food money to get myself a beefy 43-material toroid for a coax choke for my 'bug out' radio gear. Now I'm trying to locate 31-material instead that won't starve me to death! 😕☠️
EDIT: Addendum: How about the 'J' and 75-materials? At least it looks promising just by comparison with a transformer noobs eyes.
Finally: is there, to your knowledge, any 'online calculators' for impedance transformer construction that takes the core (toroid) geometry into consideration? (I'm going to check your links as soon as I'm finished writing this...) I would guess that we're changing the transformer characteristics if stacking, say three toroids, compared to using one single - since not only the wire length will increase significantly per winding, but the loops will be elongated..? We can't just be upping the power tolerance I guess, but must be altering other aspects as well.? 🤔 As you probably realize; toroid winding is still a great deal of witchcraft to me.
73 from Arctic Norway 🇳🇴!
@@michaelfuchs1467 Thanks for the reply. The links I sent you have a calculator on the page just input the lowest frequency of choice and the ohms 50 and it calculates the turns but I am not sure how accurate it is as I only noticed it yesterday. I think by adding cores you just UP the power level the toroid can handle. I am no expert by a long shot and only mention the 31 as I have researched and done my homework online for both cores and use the 31 myself. good luck with the project 73 de 2E0LIG
Paul, you so fitness man! You runner? )
I watch your videos fondly. I would like you to add Turkish subtitles to your videos.
That would be great and very helpful 😉👍 Thank you very much! 🙂
I have a question Paul... why do you need a great big high voltage capacitor when connected to the 50 ohm antenna port. By it's very nature 50 ohms is not a high voltage point... Just about any 110 pf decent quality ceramic cap should work... a pair of common 220 pf ceramic caps in series would be perfect. I notice guys ordering 3kv and 5kv caps.. that's not necessary for a 50 ohm point
Hi Richard. An explanation of this cap is in one of the links added in the video description 😉👍
I think is not necessary cut and insert crocodiles for multi band end fed antenna necessary. A 80m medium wave long wire (39mts aprox) it's a 1 wave long on 40, 2 waves of 20m, 4 on 10m (armonics bands) ... This mean that you have more gain by this way in the armonic bands and easy swr too. 73s EA4IS
Like your detail, However I have to ask why.
Other than to shorten the antenna if you’re not going to use the longer bands again my question is why. Because that antenna is multi band as you use the harmonic so if you cut it for 40 you should get 20 15 and 10.
Thanks! No, no, I want to work also on 80 and 40m as you can see it is prepared also for those bands. You can never get precise resonant points on all those bands from 80 to 10 with use of harmonics and traps. Also trapped antennas are much more narrowband than classic precisely cutted fullsized dipoles. 😉👍
Always trim cable ties flush to the buckle, not at an angle - this leaves a pointed end which can cut your hand open.
Klein Tools - these cutting pliers cut ties smooth! they’re about $10 at home dopie - in the electrical aisle.
Diagonal Cutting Pliers, Flush Cutter, Lightweight, 5-Inch
D275-5
Místo feritového prstence je ve všech SWR 1.0 lepší použít kondenzátor a obvod cívky
btw there is also 80-10m design with coil
Yes I know. But the main purpose of my experimental EFHW was the multiband construction without the coil. Also which will not use harmonics for other bands ;) 73, Paul.
@@OM0ET oh right , thanks 73
I have efhw antenna
👍
By the way, wire... I've used 1,2mm enameled wire, just I had that thickness of wire, haha. 0,7 or 0,8mm would perfectly work under 100W, but thicker is better. Ring in my case is 240-43 but I think there is not much a difference between 41 and 43 mixes. Under 1kW maybe maybe one ring could work, but might be too "hot", because anyway any trans generates heat, if someone wants to works with 1 or more kW, then wire at least 2-2,5mm thick, then at least 2 rings, also antenna wire at least 1,5mm2
Some links in your caption are dead
Ah thank you for info! I will repair the links ASAP 👍
OK, it should be good now ;)
I heard you calling CQ today on 20m, but you couldn't hear my reply.
Oh really??? That's pitty! 😔 What was your pwr and antenna?
Check out the packtenna stuff, they sell things like that
I am sorry, but I don't want buy this. I like build things 😉👍
@@OM0ET You got me wrong: i meant check em out in terms of "inspiration" for building :).
@@pulponair Thanks, yes I've seen that product. I think it was on the QRZNOW.COM website ;) 73, Paul.
Great video...please keep up the good work. But, you do realize that an EFHW antenna is inherently a multi-band antenna without all of the links because of the resonant harmonics, right?
Thanks David! :) Partially is multiband without of the links, but on most upper bands is resonance out of the band and aditional tuner is required... And the reason why I made this antenna was completely avoid tuners and additional coils, especially also on WARC bands.
Thank you, Paul! Again, thank you for the great videos!! I also use an EFHW antenna.
Well presented. Interesting lengths though... 39.73m is not 126.49 feet as you indicated it is 130.35 feet. And most indicate the length for an 80m antenna as 133-134 feet. Don't cut us short. 😁
I still think traps are a better solution, especially if the antenna is hoisted up a tree.
Aren't they will be a problem when I throw anteną on tree? Won't them catch of every brenches?
You ***don't*** have to cut the wire as it will resonant on multiple bands!
If you want to make it shorter, you can make it for 40m and add a 80 trap / resonator.
Also adding a ground connection will help, especially if the transformer is near the ground.
Sure I know it my friend 😊 but the purpose of this video was to made antenna without traps, or don't use its harmonics. Therefore I decided to made full halfwave lenghts and for WARC bands too 👍
@@OM0ET An end fed half for 80m is resonant on many bands, EVEN WITHOUT TRAPS!
@@stephenwalters9891 nice! But all bands like 80/60/40/30/20/17/15/12 and 10 without an external tuner?
@@OM0ET the multiple wave lengths will resonate. Come, this is basic stuff! You should know this!
@@stephenwalters9891 do you have any source please?
Ahoj Palo, už je dvojka?
Respektive kdy bude? Pavel OK6RP ex OK1PRI
Ahoj, pracujem na tom ;)
@@OM0ET ďakujem
Using 49:1 unun and 39,6m, Ther's no need to make the cuts. Just hang it up and it will be under 2:1 un SWR on all bands from 80 to 10m, exept 160m and 60m. You can snake it in between the trees, but try to make a part of it as an inverted "L".
Treating each wire section as it is added to make a half wave, allows him to lower the SWR even more, and then add another section with out changing what he's already set. In this, each section is actually a half wave length long and tuned to which area of the band he chooses to use the most. Plus he adds other bands, like 11 meters as well. I enjoy his videos just for those details that make it so well planned out.
@@Possumn1138 I haven't thought of it that way. Good idea! It's not that important with a good SWR match, as long as the radio gets it, but lass is more, also here:-)
And WARC??
@@OM0ET Mine has 1:1 on 12m and 1,6:1 on 17m. Works pretty good and the SWR is "workable" on all bands (No tuner needed), except on 60m and 160m. Remember to put it up as a "L" laying down. It needs a vertical component and will radiate the way the L points.
Hi Paul. Just now started to watch your video, and I have one hitch on this. "Originally it is a one band antenna", by the name theoretically it could be just one band, but in reality... this antenna could resonate more or less on all HF bands, and sometimes even 50MHz +/- with swr under 2,5-3. In my case it's test routing. Feed point about 3-4 mtrs height, second point about 2,5mtrs height, (about 20mtrs long), then bend and again about 3mtrs in height. Total lenght about 37-39mtrs. If I could tie a rope more far, then I could reach about 41-42mtrs, but hadn't a tree or some vertical bar, or somefhing else. Works on all bands, not perfectly at low bands, but works. In my case on 160m resonance is about 2MHz, on 80m it's around 3,9-4MHz. 40 under 1,5swr, 20 under 1,5swr, 17 too, 15 too, 12 near 2swr, 10 about 2,5swr (but no caps, maybe there is a case of 10mtrs). And also, no counterpoise, no ground. Might be theres is the case, but I don't think so, if there was a counterpoise, just all bands were somewhere in the moon hi 🙃 soo, I guess it's low height, some metal nearby, and lenght too small, because almost all resonances are little higher then it need to be.
1ft=0.3048m (Wikipedia)
Yes, You are correct. Problem is that both lenghts (m and ft) were calculated with different formulas. Therefore is slightly different lenght. It's still my experimental project and with real testing I will find which formula is closer to reality ;)
проводок тонковат, для такого колечка )))
На 10 ватт хватит ))
Efhw is a multi band by definition. I'm very confused by this approach and all the extra work being put in unnecessarily to cover bands that are a harmonic of the full length.
You will never get perfect SWR on all bands WARC included by using harmonics only.
@@OM0ET 1:1 might be, but under 2:1 or 1,5:1 you could get on most common harmonic bands. Why Im getting under 1,5:1 from 40 to 15-12 meters bands? And without caps. Don't need blah blah....
harmonics ????
Please read also video description
Do you have an analyzer? Why don't you use it?
Do you have a 2.4k ohm resistor? FT240-31 is not suitable. Doesn't work at all!
Tested by many people and repeatedly!
FT240-43 is OK.
How so FT-240-31 is more wide band than the FT-240-43 and covers down to 1mhz
@@Nathan1975Liggy SWR is bad. >4.
@@Arkadiy-UN8FR not in my testing
@@Nathan1975Liggy -31 material band width you speak of is only for common mode suppression. The use case here is a impedance transformer. Amidon says in the technical data of -31 material: For impedance transformers please use the 43 material
@@zuwe6622 from the amidon website
Here www.amidoncorp.com/ft-240-31/ 31 Material is used for EMI/RFI suppression in the 1 MHz to 250 MHz range.
Here www.amidoncorp.com/ft-240-43/ 43 Material is used for EMI/RFI suppression in the 20 MHz to 250 MHz range.
i propose to name it the "multi banana antenna" but is not using banana plugs after all
It’s a transformer not an un-un. Those connectors are prone to rust and could have been avoided
This is portable antenna not for permanent installation
why does this video take an hour?
OMG there is a part 2??
@@K6TJO Don't watch it if you don't like :) its on your decision