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what is your vswr at the antenna?

Discussion in 'CB Antennas' started by bob85, Jul 10, 2013.

  1. Marconi

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

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    Sorry guys, when I posted these comments to DB I must have opened a link to this old thread Bob made a while back.


     

  2. Chicago Savage

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    Hey, I've been wanting to do the double-male pl259 thing at the feed point of my mobile antenna, which has a through-the-roof mount. I went into a trusted CB shop, and he said to never do that, that I should have at least a foot of coax between the meter and the antenna. He wouldn't elaborate. What's the deal?
     
  3. Marconi

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

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    Typical response from a guy that should know, right?
     
    Chicago Savage likes this.
  4. Chicago Savage

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    I suppose. I tell you what, I'm very close to taking the Ronco approach to radio. Set it and forget it, although I've never been that type of person. Lol
     
  5. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    Only thing I can think of is the strain you would apply to the meter jack if you bumped it at all. No other reason I can possibly think of.
     
  6. Flatop

    Flatop New Member

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    I don't think road squarker fixed anything. I think the lesson in this is to not pay too close attention to your SWR because in most cases, it does not translate to much.
     
    Woody-202, Tallman and undertaker like this.
  7. Flatop

    Flatop New Member

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    I reckon Bob85 is full of shit. There are not enough parameters to calculate anything. This could be a low and insulting blow against CBers. I could be wrong about this, he may very well believe in his own bullshit. Be aware of people spreading crap, and don't fold to people just because they claim to know more than yourself.
     
  8. Flatop

    Flatop New Member

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    Road Squawker, what I said is correct. Why do you pretend to be some kind of aficionado, the feed line impedance has nothing to do with the fundamentals of standing wave ratio that I was pointing out. Please refrain from crossing out my posts in the future.
     
  9. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    I'm going to go out on a limb here, The VSWR at the antenna is irrelevant.
    The VSWR at the back of the transmitter is the only thing that counts.
    Low VSWR does not mean the antenna is resonant. The VSWR is only important for the protection of the transmitter finals.
    If you want to test for resonance use a field strength meter at 100', Make an adjustment and check to see if the RF level has increased or decreased.(Poor method)
    If you have an antenna analyzer you can better tell what is going on.(Best method)
     
    Slowmover and Shadetree Mechanic like this.
  10. The DB

    The DB Sr. Member

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    So you reckon Bob85 is "full of shit"? Why, because he gave a scenario and asked a question about it? Where is the crap in asking a question? Or were you referring to another post that you didn't quote?

    A word of advice, Bob85 is one of the most knowledgeable people on this forum. He doesn't post often, and typically when he does it is in response to the higher level tech conversations. If you are going to claim what he is saying is BS, you need more than just words.

    If you truly believe he is wrong about something demonstrate it. Explain why he is wrong, otherwise you have nothing but claims with no backing.


    The DB
     
  11. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    Like a blind dog barking in a closet.
     
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  12. The DB

    The DB Sr. Member

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    A lot of people just assume resonance means the best performance, and I see where it appears to make sense (at first glance). I have seen with my own eyes, using a remote spectrum analyzer receiver (so I am not close enough to change the reading) and comparing that to VNA measurements taken at the antenna's feed point, that it is just not the case.


    The DB
     
    Tallman likes this.
  13. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    Resonance used to mean a 50 ohm impedance, in 99 % of the cases it is not. The 1/4 wave CB antenna is between 25 to 35 ohms and is still reactive. Could be capacitive or inductive depending on the surrounding ground plane.
     
    Chicago Savage likes this.
  14. Flatop

    Flatop New Member

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    Antennas can perform better by being non resonant.
     
  15. Flatop

    Flatop New Member

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    You solve it, either yourself or Bob. Give the answer with the method and calculations.
     

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