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Yagi better than ground plane??

Discussion in 'CB Antennas' started by Andy, Feb 16, 2007.

  1. Andy

    Andy Member

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    I have access to a 3 element yagi (I'm not sure the brand) that I could put up. My question is, would a horizontal 3 element yagi at 30 feet out perform a good ground plane which would be at 40 feet when talking DX.



    Also, my yagi and ground plane would share the same mast pipe. How much separation do I need to keep between them? Because I could move the yagi higher up on the mast pipe.

    Thanks,
    Andy
     
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  2. distortion

    distortion Active Member

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    On the flatside, the beam will walk all over the groundplane to a majority of stations in DX.

    Good Luck,
    Josh
     
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  3. C2

    C2 Well-Known Member

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    The main advantage of the beam is due to its directional characteristics, especially on receive. The added gain helps too.

    However, there is the exception when the verticle's lower take-off angle will get you someplace that the beam just cannot reach. That's why it's always nice to have them both.
     
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  4. DXman

    DXman Well-Known Member

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    Yap...at least it should.

    I would think 6' min.
     
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  5. Master Chief

    Master Chief Guest

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    The answer to the first question is YES......and NO.

    A yagi and an omni are two different antennas designed to do two different jobs.

    A yagi concentrates the energy in a single direction. At 30' the take-off angle of the signal will be constant and only the changing height of the ionosphere will change where your signal will land. Its like changing the angle of the pool stick when you hit a ball off of a bumper. I'll explain it more if you want.

    Also, when a signal skips, it tumbles. Sometimes the receiving station hears you better with a vertical antenna, with you transmitting with a horizontal. And vice-versa.

    Today the vertical may work better than the horizontal. The advantage of a beam is that it directs your energy where you want it. The disadvantage is that it has to be rotated.

    If you are interested in DX, get a beam. If you want to talk to locals and the occasional DX, get a vertical.

    As far as separation goes, my number is 14.5' It is a non-resonant distance of a 1/4 wave while still being shorter than a 1/2 wave. This is theory and has worked for me. Half this distance would be 7'-3" and should work also.
     
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  6. Andy

    Andy Member

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    Thanks for your help and info.

    I don't know if this makes a difference but... I just found out that the yagi is a 4 element not a 3 element.

    I do plan on keeping my omni up. I was just wondering if it would be worth my time putting a 4 element (horizontal) yagi up. I am mostly interested in talking DX, for everything else I would use my ground plan. What's your opinion (is it worth my time)? I have the antenna and the rotor, I just didn't want to put something on the tower that really isn't going to be that much help.



    Thanks for your time and patience.

    Andy
     
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  7. Highlander_821

    Highlander_821 Amour d'Ecosse

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    Definitely worth it. A 4 element Yagi is a DX machine, for sure.
     
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  8. Master Chief

    Master Chief Guest

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  9. PA629

    PA629 Active Member

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    Personally, I think the simple fact of the yagi being directional with nulls off the sides and back is enough reason to make it a worthwhile addition, especially in crowded areas. The added gain, to me anyway, is icing on the cake.
     
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  10. Andy

    Andy Member

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    Thanks,

    I'm going to mod. my yagi according to the above website. Unless I hear differently from you guys. But I think it sounds like a good idea!

    Andy
     
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  11. KingCobra_CDX882

    KingCobra_CDX882 W9WDX Amateur Radio Club Member

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    Master Chief said all that need be said
     
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  12. Henry HPSD

    Henry HPSD Well-Known Member

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    Hello Andy,

    Im sure when u make the beam accoording the site from signalengineering you will have great results.

    When your beam has different element thickness (other then the described 5/8,1/2) you should have different element lenghts to get max out of the antenna. Though it is only marginal. (but we all want the best, isnt it?)

    73s Henry.
     
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  13. W5LZ

    W5LZ Crotchety Old Bastard

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    I'm sure that by now you've figured out that there is a benifit to having both antennas. And there's certainly nothing wrong with wanting to improve them. I would suggest that you try out the beam as 'stock' before modifying it, it'll give you a base line to see how much 'improvement' you've made. (Then of course, telling us about the differences!)
    Have fun.
    - 'Doc
     
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  14. Andy

    Andy Member

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    The more I think about it the more I'm torn on what to do. I usually work 27.385 the most but also the higher freqs a little. If I mod the antenna according to the website I will have good front to back ratio but I will lose approx 1 db which I know is not a big deal, but... If I leave it at the stock settings I will keep that db but my F/B ratio won't be as good. In my case where I live, I really don't have anyone I need to "knock out" so I'm not sure if I need a really good F/B ratio. I'm new to this so if it sounds like I don't know what I'm talking about it is because I don't :? . What are some opinions on what I should do? Should I keep the stock settings or modifiy?

    Thanks,
    Andy
     
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  15. Highlander_821

    Highlander_821 Amour d'Ecosse

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    Leave it stock.
     
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