Look ma, no counterpoise! An evaluation of a EFHW-8010

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by WA7ARK, Apr 24, 2019.

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  1. WA7ARK

    WA7ARK Ham Member QRZ Page

    No, but I will help anybody I can...
    AutoEz makes an analysis like I just posted really easy. I have amassed a huge library of different parametric antenna models. It was almost trivial to convert the Zepp antenna model I created a couple of weeks ago to DL2KQ's configuration.
     
  2. 2E0VSS

    2E0VSS Ham Member QRZ Page

    Mike,
    The Station here is exactly 7.5 metres from the feedpoint.

    Brian,
    Yes i do sir, sadly from a third floor balcony apartment....In central London too....

    Challenging to say the least but one has to do what one can.


    M
     
    Last edited: Jan 17, 2020
  3. WA7ARK

    WA7ARK Ham Member QRZ Page

    Thanks for the link to the DL2KQ design. I had never seen it before you posted the link.

    It should be of interest to those folks that have to do what you are doing, namely end-feeding a wire from one end without requiring a ground wire, ground rod, or an "artificial ground", while minimizing RF in the shack... This design (as did the original Zepp antenna) cleverly uses the "unconnected" wire in the twin-lead as the "counterpoise", so is "ground independent", like a transformer-fed EFHW uses the first few feet of coax as its "other part".
     
    Last edited: Jan 17, 2020
  4. 2E0VSS

    2E0VSS Ham Member QRZ Page

    Mike
    Exactly,...And his L values were spot on for 80, and 40Metres as was his C value for the 20 metre band...
    I fabricated it using the choke from the mind of Wolfgang Wippermann DG0SA (SK) and the two seperate 80 and 40 inductors (interchangeable) wound at 32uH and 6uH respectively.
    His C value ended up being 22 pf.

    I can of course feed the base of the 7.5 metre 600 ohm directly from the Link coupled out of my KW107 supermatch which is an option too but i wanted to see how close his calculations were in the real world with a homebrew one capacitor or one inductor tuner.
    All in all it was mightily close to his calculations...

    I urge all hams with an interest in antennas to maybe think outside of the box and Google translate (Igor Goncharenko) DL2KQs site, he is one of the worlds leading antenna elmers and the Forum on there is extremely interesting too.

    Have a nice weekend..

    M
     
    Last edited: Jan 17, 2020
  5. KE4LH

    KE4LH Ham Member QRZ Page

    I would propose that "we" as a collective group keep an open mind. There are today, many different types of antenna designs including those with patents that Do Not Follow conventional thinking. For instance, much of this thread time is spent discussing the counterpoise, delay line, in some cases the ground plane, or simply the return path. Yes, all conventional 'antennas' require a return path, but,.. there are designs that do not. I need only to direct one to the commonly called "magnetic loop" which does not require a ground plane. I would challenge your thinking to take a closer look at it, since in reality it's not a conventional 'antenna' at all. It is a coupler. Many of you who understand electronics know what a rf coupler is. So, I ask you, fellow amateurs and experimenters, try to keep an open mind, and learn, instead of just blindly quoting the books. Books/Rules are always changing, keep that in mind when looking at new or unusual designs. I could tell you of an antenna which, like the magnetic loop, needs no counterpoise, and its size is on par with same, but is the electrical/capacitive version of the loop aforementioned.

    I only mention these facts because it's disappointing to see so much...... discussion about a single subject. When the point of the whole matter is forgotten. Wasn't this supposed to be an article about a easy to put up, multiband antenna made with common parts? And of course it works, any conductor with rf energy will radiate, how well has already been documented, at least when you talk about antennas like this one. These are old school, dipoles are old school, and yes, old school works. But there is so much more out there to learn.! For the same reason we should all be driving cars that don't use gas, the same reason exits about antennas.....

    We should find it refreshing to find someone who has put so much effort into providing us with a multiband design that can be used in so many situations. Solving a problem for many, with no cost to you. Saving hours of your time, and money........ and even if it didn't work well for your installation, you have a good starting point to work from... isn't that worth something?
     
    Last edited: Jul 17, 2020
  6. K6BRN

    K6BRN XML Subscriber QRZ Page

    Thomas (KE4LH):

    This is an OLD thread. Lots of debate on what works and what does not on the forums, and what is "Best". No need to worry - it's the (pretty normal) "Human Condition".

    Mike, WA7ARK (see above posts, including one where I poke a little fun at him) did some great work in modelling EFHW-8010 wire antennas - and then proceeded to correlate his models to actual use and physical/electrical findings. Then published a great chart deck on the topic. Genuinely helpful to the community and I've always applauded his efforts.

    Previously, a bunch of armchair ... ahhh... experts had grandly predicted that the maker of this antenna was lying, "stealing hams precious $$$$", it was impossible, violates the laws of physics, etc. Of course, they are some of the more popular antennas today and work just fine. Any required counterpoise can be provided by the shield in the coax and only a few feet seems adequate for best operatinn. So the user really does not need to worry about this. And even if you place a CMC right at the feedpoint, they still work, but perhaps are not at their absolute best. This is the difference between blind simulation/speculation and cross-checked and validated results.

    Regarding a current return from the antenna - in the end, changing current flow through the antenna is what creates the electric and magntic fields that merge to form the EM field that radiates from the antenna. Any current moving into a device has to return to the source (be "referenced to the source") by some path and mechanism. The problem is - there are a LOT of mechanisms for this current return to happen in high frequency AC systems - straight DC analysis is not adequate and those trying to apply Kirchoff's current law as if this is a DC system and not taking other paths and effects into account - have issues.

    This is another forum "hot topic", BTW. Hopefully I'm not starting another "Forest Fire" here. "NO! IT CAN'T BE: KIRCHOFF SAYS .... !!!!!!!!" (Sorry folks - Kirchoff said his current law works only if you actually understand the current paths)

    So... you like alternate antennas including magnetic loops? GREAT! Carry on Thomas! The ONLY rule is that you should be having fun - this is a hobby, after all - that's the whole point. And if you build and demonstrate an antenna that seems to work well and is "Impossible", excellent! Haul that puppy out so the community can look at it and maybe (just maybe - we're an amateur community, after all) figure out HOW it's working. Because it's really, really hard to argue that a device violates the laws of physics if it actually ... works. And experimentation is part of the fun.

    Brian - K6BRN
     
  7. K1LKP

    K1LKP Platinum Subscriber Platinum Subscriber QRZ Page

    HI MARK,

    GREETINGS FROM SALEM, NH.

    THANK YOU FOR THE HEADS UP ON IGOR'S SUPER ANTENNA SITE......BRAVO

    WHEN I SAW THE PIX ON YOUR QRZ SITE.
    OPEN WIRE FEEDERS LOGRITHMIC SPACING.jpg

    I RECALL YEARS AGO WHEN THE OLE TIMERS WOULD
    BUILD THEIR OWN HOMEBREW FEEDERS THEY
    USED A SCHEME THAT WAS REFERRED TO AS
    LOGARITHMIC SPACING.

    AGAIN, THANK YOU

    AND

    Hats_off[1].gif

    73 - K1LKP
     
  8. KE4LH

    KE4LH Ham Member QRZ Page

    Putting an antenna discussion on a public forum is like setting your foot on fire with gasoline and trying to put it out with alcohol. It may work, .... if you're lucky.

    Hi Brian, good to here a response. :)
    It it so very sad that today's "Antenna theory" is actually 100 years old. And when someone introduces a new design, it is typically ridiculed without ever having even been tested. Terms like snake oil and fake, and "it can't work" are the norm. It takes a certain amount of bravery to introduce a new design because of these very facts. (And yes there are certainly false claims out there, particularly regarding CB antennas) But as I asked above, "Why can't we be civilized about this and at least test it before making statements "....

    I have been working with rf for decades. Probably like a great many of the readers here. But I have seen designs that are NOT in any Antenna book, and work far beyond what the "book" says. And BTW, what is the book? There is no such thing as physics when it comes to antennas. I hear that all the time, "that can't work, it defies physics". There is no such thing, or book. There are good working theories, and a ton of gathered data. But what does all that data add up to? Most discussions point to "antenna current" or "antenna voltage at this point or that"... See what I mean? Voltage, current....., add up to impedance,.. those are simply things you can measure with somewhat primitive equipment, no matter how accurate it is. Why? Because no one can answer this one simple question: "How does a rf signal travel from one place to another?" No engineer can tell you because they don't know!! Just like you can't see light, only what it reflects off of. So before I am going to open my mouth about a design, I will study it and study it some more, and limit my comments to facts, if I have any... Because unless you actually do build or acquire, and test, then you have no facts except for experience perhaps from having done it already.

    So I hesitate to mention anything new on a public forum,.... but I do enjoy the hobby and the experimentation, and the study of others work, it can save hours of precious time. And I also seek a like mind for experimentation.....
    Tom - Ke4LH
    Have you ever seen an electron, do you know where they go at night?
     
  9. K6BRN

    K6BRN XML Subscriber QRZ Page

    Hi Tom (KE4LH):

    No need to be too shy. You have nothing to prove. The forums hav zero affect on your real life, unless you let them.

    Our understanding of the universe is based on our observations and models we construct, consciously or not, to predict cause, effect and likely events. They are good enough to get by and are often superceeded by better ones. That is science. Application of those models to build tools, hopefully to make our lives better, is engineering. Complete and total understanding of the universe is not in the cards at the present time. So why worry about it?

    But there are very, very good engineers and scientists that understand our observations, models and the driving thoughts behind them incredibly well. The very best rarely say "That's Impossible!" Instead, they have the ability to "Ask the right questions", more often than not. Very often those questions include "What ARE your observations" and "What COULD explain those observations". Almost all new critical technology has been developed by breaking preconceptions.

    Thomas Edison is often cited as a genius. But his real accomplishment was putting invention on an industrial, assembly-line basis - then trying almost everything and anything to make an idea work, including making a lamp filament out of Tungsten metal ("Impossible" at the time). The ideas were often were not his, even though he "owned" them because of his labor contracts. Tesla worked for Edison and proposed the idea of researching a polyphase AC system of electrical distribution and motors. Edison turned him down and believed the idea too far-fetched to be practical. "Impossible". One really big mistake among many, many successes. So don't be TOO hard on the forum. As I said, its part of the human condition.

    Best Regards,

    Brian - K6BRN
     
    AK5B likes this.
  10. W9XMT

    W9XMT Ham Member QRZ Page

    Regardless of that concept though, probably one is better off not looking directly at the Sun.
     

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