The Zepp antenna is essentially a J-Pole antenna. The quarter wave of ladder line transforms the high impedance at the end of the half wave antenna to a lower impedance 1/4 wave along the ladder line. That wire is not a counterpoise. The counterpoise for a half wave antenna has very low current (like at the end of a dipole antenna). In my experience it doesn't need to be any particular length.

The reason for the slightly screwy SWR dips on 20 and 10 is that you would need to add a loading coil about 6 feet or so from the transformer - this helps to bring resonance to the higher bands. This design is used by myantennas and Hyendfed in their efhw antennas designed for 80-10m. 73

One of the best videos you have ever produced, cheers Kevin, 73s AE1TP A92GW

Thanks Kevin, great video on this end-fed zepp type antenna. You experiments help with analysing and problem solving of my antenna builds. :)

That's a great project there, how cool, thanks for sharing! I just constructed a full wave loop and got it operational, it has a lower noise level too.

saw what Callum was doing for you for gas money too cool. Shows that you tubers are a great family and help each other out. Too cool. Glad you will make it across the country and glad you got the help needed. Thank you for your help in all the videos you make to teach others.

For me, the AA5TB article on EFHW antennas is so far most knowledgeable piece if theory proved by his practical experiments. I've tried everything he writes myself and can confirm it works. Especially the part on 0,05 w/l short counterpoise. The part on stray capacitance also works :), just be ready for some funny things going with your radio ir even your car's electronics ( my own experience) after you put 100W into this "stray capacitance" assembly. The best EFHW antenna is monoband fed via the tuned to resonance circuit. The part of the article on tuning with the help of 2,7 k resistor is very educational too. BTW , the German ham company QRPprojects used to have a nice "Fuchs antenna" kit. I have made one myself under their description and it works very nicely. The 49:1 transformers got very popular with the emergence of modern cores and also work very nice. But in no way they deny the aforementionned theory. I have at least 4 EFHW antennas in use of various designs for many years now: one full size 80-10m transformer fed as a very effective fixed station antenna, one full size portable transformer-fed 80-10, one portable 40-10 with the trap for the 30m band and a qrp 40-10 LC-tuned Fuchs type. The latter proved to be extremely effective used with the simple qrp rigs as a Mountain Topper and others since the tuned resonant LC circuit brings more selectivity on RX and filtering on TX. Thanks for a nice video and experimentation! 73! Linas LY2H.

Kevin, another great contribution to the HAM community. Good job as usual on UTOOB, Good idea on using ZEP style counter-poise instead of coax shield. The imagination gets activated about varying the lengths of the aerial's elements using clips/connectors/fold-backs, whatever, for portable/mobile ops on different bands to minimise tuner losses. Every Bittle-Lit counts while QRPing! Been going to assemble a 40Mtr EFHW for my QCX rig for months but have been using Random Lengths instead. You just showed us a good clean way of doing it with EFHFs. Tnx/Regards/73 Russ in NH KA1RUW

Love the EFHW antenna for /portable. Keep up the great videos.

I like the idea Ono the builtin counterpoise! It looks like a nice portable antenna where a dipole would not work. Thank you for this nice video.

Winding toroids. I just finished building a Elecraft K2 with all the add-ones and external 100 watt tuner. In total 45 toroids. You have to learn to love it.

Excellent build will try for sure

Hi their Kevin. The first thing that comes to mind on the subject of the "Zepp" antenna is has mentioned the high voltage at the end of a half wave. In Germany I had a 132ft 80m halfwave wire up from my chimney stack accross to my mates chimney stack. The wire was well insulated at both ends. The feed point termination was a 2mm socket. a fly lead connected this to a ATU. The earth was flatened braid from a long roll of coax that had been discarded and stripped down. I had use of a 600 watt soldering iron that I was able to solder the braid to fairly new garden fence wire that ran under the antenna. This joined up with a bonding to the incomming cold water supply in the cellar. This had to go all the way up to the atick window into my shack. I found that the "Earth" was working by watching a 1" spark from the disconnected antenna to the earth terminal during an incoming storm. I was a bit concerned that my ATU would glow like an elecric fire and what sort of voltage would my valve preamp be getting every time there was a storm in the area. Beside the antenna being great for pulling in VK, Ws and you name it. It was great for pulling in Radio Caroline to witch was wired down into the flat for my XYL to listen to. So Kevin with a 1" spark to ground from a 132ft length of wire at 50ft up. What kind of spark would a "Zepp" antenna give with either a atmospheric charge on it or from a transmitted charge on it when getting landing permission on comming in. With a ferking big bang and a hell of a flash as gas is ignited of a Zeppelin airship coming into land along time ago ?. Sorry for all of the story of the 80m halfwave wire. It just came straight to minde of the discharging spark to ground from that antenna. That was in 1965/6. But you do tend to remmember those sort of things. 73 de John - G0WXU.

Hi Kevin, Appears to work well. Nice build portion on the transformer. Looking forward the the interview with Cal. Made a contact with them a few weeks ago as M0XXT/P 73 WB3BJU

Great experiment I am waiting on caps to come then will be constructing similar. As always great video Kevin, 73 ZL1MY

Steve Ellington did not design it but he certainly perfected it to the point of mastery.

Should be a dead-easy antenna build. Your videos are well designed and easy to follow. Your hit into Europe may be thanks to your location on the coast. Hope all is well and enjoy the Texas hospitality. 73 W0YVY

Great vid Kevin. I also use a ~130' wire with an unun, but with multiple taps. On 80 I can cover the whole band with an SWR of < 3:1 with 300 KHz of it < 2:1 by using two different taps. I have no ground attached to the unun. I see absolutely no change in SWR when I attach an extensive ground radial system to the unun. The rig is grounded via a simple ground rod outside the window. I can cover all bands up to 12m and generally cover the whole bands with an SWR much less than 1.5:1 by using two taps. This assumes that the wire has been trimmed to resonate on 3.600. 10m is more problematic for me. The thing works excellent on 80.. but on 20, when compared to my vertical, often times a signal cant even be heard on the wire yet be pounding in at S9+ on the vertical. I also use the wire on 160 and have worked almost a dozen states.. but using 100w. It resonates at 1.820 there. I have no counterpoise at all. My 'feedline' is 1.5' of coax running from the unun (on my wall) to the rig. I have almost no feedline loss.. so I generally don't use the auto tuner.. not wanting to add loss needlessly. Thank you for the fun videos! 73 OM

Thank you for sharing your experiments. I always learn something and that's what makes this fun. I'm about to put a solar powered HF radio on the air and I was going to use a random length end fed wire bur now I'm reconsidering. I don't think I have space for 127 feet of wire, but I'll measure to see.

Kevin, completely understand SWR, but can you do a video and talk about different ways (theoretical and experimental) to evaluate radiating efficiency? Awesome videos by the way, love ‘em!!

If you're curious why the resonant point sneaks upwards as you move through the bands, I did a short discussion on the topic: kzfaq.info/get/bejne/orZjbLmrrt6pZKc.html

I have studied this and have found variations adjusting the capacitor in relation to the skew deg and the hedge of the antenna

i know the video is older but I found a number of good resources that explains you don't need a counterpoise for resonant half wave antennas. If wire is too short for the band, you would than need a counterpoise. Check out Hyendfed antennas as a commercial reference to what I am saying. Also the qrp transformer in upur video is 64:1 with turns adjusted for the size of the toroid and other factors. The Radio Prepper guy in Europe did a really good analysis of this theory.

Interesting Antenna! :D

Great build brother. Might try to build one for 40, 20 and 10. My main problem at the moment is the fact that I am getting an insane amount of RFI because I live in NYC :(

Great video!!! Have a look at an azimuth directivity plot for an EFHW.... my modeling (at 2nd and 3rd harmonics) shows gain off the ends of the wire, unlike the gain mostly in the broadside direction for a dipole. This should be part of anyone's planning for how/where to erect this antenna.

I’m gonna try to make one of these Thanks ! Take care! 73 de ve3hip in welland Ontario Canada 🇨🇦

Hi Kevin. Nice video with some good info. As others have pointed out, that isn't an "auto-transformer". It's a bifiler wound transformer with both conductors joined on one end of the transformer. An auto-transformer is essentially a coil with a tap part way along the coil. One side of the transformer uses the two ends of the coil, and the other side of the transformer uses one end and the tap. Both sides of the transformer share the part of the coil between the shared end and the tap. The drawing of the end-fed antenna with the parallel counterpoise appears to be just a "zepp", or "j-pole" antenna. The patent drawing includes what appears to be a balun or unun. Could be for impedance matching I suppose. May also be for feedline isolation; to prevent RF on the feedline or to prevent static/lightening from coming up to the radio. I've used 1/2" copper tubing j-poles on 2 meters for years and they do work great! Cheers, Alan

However, the Idea with Zeppelin Antenna was _not_ a Counterpoise, but Impedance Matching.. :D The Twin-Lead Part with Ladder-Line or Window-Line or something like that, of the Zeppelin Antenna is 1/4 Lambda long. But that works in a Way, that at the End of an _open_ Feed-Line that is 1/4 Lambda long, the Impedance is changed into the Opposite.. So since the Feed Line is open, it means, the Impedance at the End of it is high, but at the Transmitter / Receiver it is low. Means, the high Impedance of a connected 1/2 Lambda Wire will be low Impedance at the Transmitter / Receiver.. :D The Zeppelin Antenna is in total 3/4 Lambda (for the lowest Band) long. The 1/4 Lambda long Twin-Lead Part _is open at the Transmitter / Receiver and at the Antenna_ ... The J-Pole Antenna is different in a Way, because the Impedance Matching Part, is done with a at one Side shorted 1/4 Lambda "Feed Line" Part and a "Tap" for 50 Ohm. But both Antennas have in common that they are about 3/4 Lambda long and that they do the Impedance Matching with a 1/4 Lambda Part, that basically is _in a Way_ "Feed Line".

Parts used with part numbers & cost for parts and build would Be a nice touch for your videos. Thank you

Interesting idea. I wonder how it compares to the standard counterpoise configuration. I just let my counterpoise drop from the feed point and lay the remainder of the wire on the ground in the opposite direction to the hot side. With the original Zepp design I was under the impression that the ladder line was the transformer taking advantage of the fact that a quarter wave transmission line converts high impedance to low impedance. Still an interesting experiment. It might be interesting to make some rf current measurements.

Nice video. It might be interesting to compare performance on receive to an equal length of wire.

I suppose Steve E. and EFHW group on FB could explain more on this design.

Great video Kevin. I bought one from Alpha antenna but the transformer was a 4:1 Un-Un. The feed point had to be up very high for it to get out.. hot side was 75 feet long and the shorter leg was 25 inch. They worked well from the blimps because of the elevation. I’m curious to see the performance on yours with the 49:1. Also the alpha version didn’t use window line. It was two wires with the jackets fused together like lamp cord. Great stuff I enjoy your channel. Art. K2ADC

Thinking further, I'm really not sure what the point of the parallel 'counterpoise' is. The coupling will introduce some capacitance, so in theory that will bring the resonance down in frequency. But with wires that size and at that distance, the C will just be a few pF, so will effectively do nothing.

Good information and welcome to Texas!! Looking for something like that for my 5th wheel, and really, for home as well since I have limited space. Thanks!! 73 de KI5DLS

Very interesting👍

That QRP guys transformer is 24/3 so 64:1 on the transformation ratio.

0:46 4:14 This is not an autotransformer. 3:17 An EFHW does not explicitly "need" a counterpoise as experiments confirm. Interesting project nonetheless.

Thank you for the informative video sir! 73 de AC6GM!

I take it you didn't ground the transformer like you normally would on an efhw. Interesting design. I might just give that thing a try. Great video as always.

Interesting stuff and very useful thank-you. At 2'56" I guess you worked out that the QRP Guys are not actually using a 49:1 ratio but the other common ratio of 64:1. This is made up of 3 primary turns to 24 secondary. A moot point I know but wonder if this ratio would move the SWR dips to another part of the bands?

Thanks for the video Kevin. I liked the idea of having just one "lump" of wire to string up. This got me thinking: I wondered if you could try extending the half-wave section by 0.05 lambda (i.e. same length as the window line)? This would perhaps mean that the the antenna becomes a modified j-pole where the window line is acting as a 0.05 lambda matching section. Unlike the j-pole which needs 0.25 lamda length of matching line, the 1:49 transformer means you can feed it at the much higher feed point at the start of 0.05 lamda length of line? Perhaps your antenna is actually working in this mode?? One problem is this the antenna would be balanced. So, might need to use separate primary/secondary windings on the transformer or perhaps put a current choke on the co-ax. I think I might have a go at making one like this to see how it works? Thanks for the inspiration.

Interesing. I have plans to build an End Fed Soon.

I've build a similar antenna using FT240-31 core not a long time ago. Interestingly it works a little bit differently than those antennas using mix 43. The antenna works OK on 20, 30 and 40 meters, and also on 15 and 17 if you don't mind SWR 2.5. I didn't manage to make the antenna work on 10 meters no metter how I tried. One drawback I noticed is that when you operate FT8 for a long time (e.g. 30 minutes using 30W calling CQ), the core gets quite warm. This is not a problem per se, but it affects the capacitor which is not an NP0 one, thus the SWR rises quite noticeably. Did you notice a similar behaviour of your antenna? Sadly most people who make end fed antennas prefer not to test them under the load, thus I can't tell wheter it's a common problem or only the problem of my item. 73 de R2AUK

The section of the antenna that contains the radiator and counterpoise looks to be a section of transmission line (fairly high impedance). If it's a quarter-wave in length, then it could be viewed as a quarter-wave transformer. Such transformers will flip the impedance from one side of their own characteristic impedance to the other. The analysis I've described here should also be true.

Hi Kevin, love all your vids. great source of information. just wanted to confirm something... You said that the 0.5 Lambda counterpoise for 80m band is 2m long, whereas on my calculator is is 4m. Am I missing something here? Just want to have clarity, as I tend to use 4m, although recently not with low SWR, but it's rather the parts around the toroid or so. thanks for your reply. This version with the ladder line looks great if we want to use it on 10m long fishing rod or so for 20m band or for 80, 40 bands as inverted L. take care

If the counterpoise is 1/4 wave does that not make it a Zeppelin ant and does it still need matching to 50ohms?

Did you try it on 160m Kevin? I know its designed for 80m. But I would like a 160m antenna ( up to 40m) but don’t have 264’ of garden space 😂 i wondered if this would be an improvement on the ‘long wire’ I currently use🤔

Interesting. It looks like an OCF Dipole.

Thanks Kevin. This is very similar to my EFHW that I've been using for a year or so. I have the same transformer built from a 240-43 and I use it at 100W for SSB most of the time. The length is cut for 40m and I have a loading coil in place to make it work on 80m and it does really well. It's quite low at only about 5m off the ground. My question is about the alignment of this type of antenna? Is it strongest side to side of the wire or along the length of it?

Thanks for the vid. I’ve been pulling my hair trying to figure out what antenna to use for my living arrangements. I live on a second floor with a few trees in front of my balcony. It’s perfect for hangin just one dipole. So whichever I pick I’m just restricted to one band. This antenna gives me the chance to make it for 40m and also use it in 20 too. So just to make sure, this antenna doesn’t need a ground connection? Since I live in the second floor I can’t have a ground rod to attach the ground like in the case of a regular end fed. 73, KY4DA

I was of the understanding that the counterpoise should run perpendicular to the radiator? Thank you for the video, subscribed... 73 M7LTR Edit I see from the comments and your following video of your findings... good work and very helpful

What's the point of having the 2 turns of the primary twisted together?

Did you notice much directivity with it? I would imagine strung horizontal it would have a null off of the ends. I've noted those nulls aren't as deep when the antenna is closer to the ground, just curious if you noted anything like that.

Yo Kevin!: GREAT video! Enjoyed your new video. I'm going to put in another request for my audio transformer idea antenna, you've done wacky ideas in the past, don't see why this wouldn't be a worthy project! VY 73's (See you're heading east again? Destination? : ) de seeker/Jeff WA7LFP

Looks very much like a zepp antenna or J pole (another version of a zepp). I like it better then putting a ugly balun in line.'

What transformer would/could you use. Learning this stuff now so any 'basic' tips on that ?

Same circuit but try a 240-52 torriod. More efficient.

Thanks Kevin...73

Afternoon Kevin, Great video. Have you thought of selling these on Ebay? Take care. JJK

Stay away from 27mhz as that insulation will melt because of the resonant frequency of Chlorine that will be used to make the insulation on that bell wire.

Are you in Corpus? I just moved from there. I was watching your video's and just realized you were in my hometown. Did you ever meet with the club at the Lexington? I worked on some equipment there one day, but it was just as the last hurricane hit and everything went south quick.

Do you have lots of noise due to the tendency of efh or have you found a way to mitigate that? I love my antenna, but don't love the noise. Also, my antenna was supposed to be made for 80 m however I can't pull in 80 m, I can get 40 but no 80 frustrating sometimes

I don't understand why a a halfwave dipole fed at the end (endfed halfwave antenna) needs a counterpoise of some kind. If the dipole were fed in the middle, no counterpoise would be necessary. Why is this not the case with an endfed halfwave antenna?

The “zep” a.k.a. the “J-Pole” .. if you directly connect, and find experimentally the dip point, you don’t need the balun …

Adding a counterpoise to an EFHW doesn't that make it an OCF dipole?

At 2:00 a 9:1 is removed. Is that an 81:1 in comparison with the 7winding 49:1? Thanks

I use the W3EDP end-fed instead of a Zepp. I put a 4:1 balun on the window line, which is 17 feet long, then 66 feet alone on the radiator side of the window line. That's a full-size W3EDP. A half-size works fine as well, you just bring it up a band. My full-size works fine on 160-6, and the half-size I used last winter worked fine from 80-6. For a balun, I just use an LDG 4:1, sealed for weather. My full-size is arranged in inverted-L form, the 17 feet of window line going up the side of my house to the suspension point at the top of mast over a disused chimney. Then the radiator goes off sloping down into the backyard, tying off on a disused clothesline pole. I can tune it up great with the tuner in my KX3 or KXPA100. It's NOT a resonant antenna and requires a tuner. This site was the inspiration. I use regular window line instead of TV twinlead. thewakesileave.wordpress.com/2016/05/22/a-flimsy-w3edp-portable-antenna-la-manquita/

AaaI found ur half wave ant very interesting as I reside in a retirement village 73 Mike VK3AUR

Have you ever considered modeling your experiments with EZNEC or other modeling software prior to building then comparing the results?

I'm not disputing the HV. 100 pF cap. but I'm a bit baffled by it. The self-capacity of coax hovers around 30pf / foot depending upon type so 20' of coax will already present 600pf across the low Z winding. Anybody got ant thoughts on this? 73 G3NBY

I think 123 feet would be the ideal length to avoid harmonics on multiple bands. Which means 10 thru 40..

Greetings Kevin , could you tell me what gain have the EFHW antenna. Excellent your video W4EDY

Do you have any info on those capacitors?

Wow....the TX/RX relay on that IC-7300 is noisy!!

This is not far from a W3EDP antenna. Have you analyzed one? Could you analyze one?

You mention the twisted wire being harder to wind. Is there a reason that you're twisting it? I would have thought that simple bi-filer winding would work. Or even a true auto-transformer (single winding with a tap). Do you have a pointer to documentation as to why the twisting is preferred? Thanks. (de KE1G)

In what way(s) is the southern coast of Texas different than the rest of the USA?

It's a big J-Pole.

👍

Hi ! Kevin !

A 3turn to 30turn xmfr=10:1 turns ratio; which yields a 10^2 (100) Z ratio. Why are you incorrectly calling it a 49:1?

Why not just feed the half-wave wire with a quarter-wave length of ladder, short the ends together creating a stub, then feeding the coax in at the 50R point, which will be not far from the shorted end? No counterpoise required, no cores to get warm, much less hassle. And if you have enough real estate, add another half-wave wire to the other wire at the top of the stub, to get around 3dB gain?

Kevin......Some hams prefer using a 9:1 balun. What's the advantage/disadvantage of a 49:1 configuration as opposed to a 9:1?

Could you make a 1/4 wave version

I have some news for you, that transformer is 64:1 and it is NOT a UNUN.

Really interesting project Kevin and I will be trying this on my EFHW which has same response on 20m as yours. Also Steve E. Antenna Utube article with a 5 turn coil on 1 inch former : refer to kzfaq.info/get/bejne/kJ1debyem9iZmpc.html about 7feet from transformer, this lowers resonants of various bands especially useful for CW areas of the bands.

If your balun is wound 24:3 turns (diagram) how is that 49:1? My math says it is 8:1, similar to the usual 9:1balun. Your 14:2 is just 7:1, no 49 there either. What's your math? Where is 49 coming from?

Looks like a J-pole to me?

Here's a challenge - I need an indoor 40 meter antenna that's still efficient. ;)

can 300 ohms tv line used?

There is no need for a counter poise on an EFHW.

It helps to operate from the equivalent of ham radio heaven. From the FCC ground conductivity map it appears you are in a sweet spot. My QTH is one of the worst areas. radio-timetraveller.blogspot.com/2011/06/field-strength-calculations-ground.html Big signals can be heard from the Texas gulf coast, with QRP power.

QRPguys are 64:1.

Counter poise 1/4 wave added to a half wave dipole is what? So much wrong here man. Cut the cp off and build a correct 49:1 transformer. Ground the coax and try again

The so called "counterpoise" won't radiate or help with decoupling...All it's doing is removing 6 or 7 feet from the total antenna length...Two wire line is self shielding...No signal egress on HF with spacing that close...Need at least two feet.

I am confused why the 49 to 1 transformer wound in this configuration even works?? the first 7 turns are wound CW right hand rule and the second set of 7 turns are CCW right hand rule the voltage produced should cancel. like two wingdings coil dot opposite. is it, that each coil is presenting an impedance in parallel. that matches to the 50 ohms. the attached google link picture explains. The reason the primary is wound tight on secondary is that at high frequencies the core is mostly transparent no coupling through the core only through capacitance of close winding to secondary. What are your thoughts? thanks N7RBC .drive.google.com/file/d/1Ei2uZxOjWDzubLDgEIrn4f-x51WOp0CW/view?usp=sharing

No

Stick two wires into a potato .. you get a capacitater …