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New thread to debate V-4000

Discussion in 'CB Antennas' started by nosepc, Nov 12, 2013.

  1. The DB

    The DB Sr. Member

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    I didn't say there wouldn't be more loss in a stub match, I only said you would likely never notice the difference. Look at the length of coax you are using for the stub match, in most cases the stub is less than 1/4 electrical wavelength long. And even if it is a bit longer, there simply isn't enough electrical length, even in worst case conditions, for said losses to add up to a noticeable amount. Also using higher quality coax will reduce them further, not that you would notice even that at CB frequencies.

    When it comes to power handling capability, a said stub will be acting in part as a transformer to change impedance, you will have higher voltages than if the signal was matched. Because of this you do need to use feedline that can handle the increased voltage for whatever power you are planning on running. It is the voltage component of power that causes the feedline to fail after all. That being said, I think that the ability to account for said voltages is within the abilities of most people who can calculate a stub match, and even if someone can't, just get the expensive stuff that is way overkill for your needs, its not like you need a lot of it...


    The DB

     

  2. bob85

    bob85 Supporting Member

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    i know you understand that DB,
    you are not average joe thinking he bought something better than a conventional shunt feed setup;),

    do you have any thoughts on why the coaxial choke was causing vswr issues in the review?
     
    #437 bob85, Sep 15, 2014
    Last edited: Sep 15, 2014
  3. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    Bob, where did you see the review?
     
  4. The DB

    The DB Sr. Member

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    I haven't seen the review, and am not aware of the review you are referring to. Do you have a link? I'm happy to take a look at it.


    The DB
     
  5. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    DB, neither am I.

    I asked Bob where he saw the review that he asked you about in his post to you above.

    I'm going to take a wild guess here that you and Bob were talking about the new Vortex antenna that looks like a Vector.

    Maybe there was a review on their Website that I missed, so I asked Bob. I didn't want to go back and reread this thread trying to figure out what he was wanting you to talk about...when he asked you for your thoughts.
     
    #440 Marconi, Sep 16, 2014
    Last edited: Sep 16, 2014
  6. The DB

    The DB Sr. Member

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    Think I found it, this one?

    If it is it is almost like he mentioned it as an afterthought. He does love to ramble about nothing doesn't he... Anyway...


    Unfortunately I don't know what specific issues it was causing so its hard to say. It could have simply had a bad connector on one side of the choke, or perhaps the coax piece used to make the choke was bad, or any number of other things... As far as I know he may have simply forgotten to set the forward setting on his meter before checking the SWR...

    The fact that he has an antenna that is using a stub match, if the choke was on the feedline after the stub and not in the coaxial stub at the antenna (which is where I would put it if I had enough coax to work with), such common mode currents would potentially have an effect on the stub match. The Vortex site says that it is a DC grounded antenna, assuming the DC grounding is from them using a shorted stub, that would potentially provide a path for the common mode currents to get inside the coax. If said currents could make their way inside the coax before or at some point in a stub match, the stub would have to work with an additional RF source it was never designed to address. Removing the choke, or even moving it, should affect the amount of common mode currents are on the line as a whole, which in his case he may have been lucky enough that said currents were lowered to the point of being a non-issue.

    In his case, assuming he doesn't have enough coax in the stub to make a choke at the antenna, I might recommend some ferrite clip on beads to be attached near the antenna as another means of controlling cmc's.

    Again, this is just a thought. The information given to work with on the subject is limited...


    The DB
     
  7. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    DB, it is strange to me how differently folks consider the nature of others. To the contrary...I often see Bob to be overly brief and focused like an Eagle on the topics on his mind. He is far from rambling.

    He does take us for granted, that we are fully in tune with his thinking sometimes. To me, that may means he has high expectations.

    Dave just said the choke presented a problem and mentioned a connector(s). If that is the case then, I think he added coax to his antenna system using a removable choke, and maybe the antenna was presenting just enough reactance at the feed point...that the resulting setup went south...so-to-speak.
     
  8. bob85

    bob85 Supporting Member

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    DB
    in the first part of his review dave says it is a vortex choke, i was in the mind that providing the connectors are all good there must be common mode on the coax for the choke to mess with vswr,
    im sure its a strong antenna, with a few changes it could be a very good antenna imho,

    eddie,
    me and DB have not been talking other than what you read here on the forum,
    you could be right my wife often says to me "im not a mind reader"
     
  9. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    Bob, I think I'll wait until Nospec gets back off of vacation and tell him what you said...and then I'll ask him to respond, because your remarks went right over my head.:LOL:

    Or, maybe I should go lay down.
     
  10. bob85

    bob85 Supporting Member

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    eddie
    vortex make 4 styles of vertical antenna,
    j-pole
    slim-jim
    quasar Q64 with stub matching
    quasar Q82 based on the sigma4/vector

    i posted a link to the new Q82 as it is a sigma/vector style antenna, rob jeff and myself commented on its construction,
    http://www.vortexantennas.co.uk/shop/q82-vertical-11m/



    henry mentioned stub matching which i know is the Q64 antenna,
    myself and DB were talking about the Q64 which may have confused you,

    a member on here, dave m0ogy has multi-part reviews on youtube of the vortex slim-jim and vortex quasar Q64




    i hope that clears up what's going on in this thread.
     
  11. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    Yes Bob, that helps. I just didn't have the energy to look back over 400 post and try to get up to speed.

    I think that stub business looks like a test I use to do to check a 1/4 wave jumper line I made using a dummy load as the antenna.

    Thanks.
     

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