New truck cb/antenna issues,why?

Discussion in 'CB Radio Forum' started by craig_sez, Jul 15, 2021.

  1. Night Stalker10

    Night Stalker10 Road Train Member

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    How long is the riser?
     
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  3. Meteorgray

    Meteorgray Heavy Load Member

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    Ridgeline, I see where you got some of the info about the question of what a vehicle represents: a ground plane, a counterpoise, etc. The info came from the famous kObg site that Craig-sez cited in Post #1.

    Here are a couple of quotes from that site:

    ..."A vehicle is not a ground plane, but rather acts like a capacitor between the antenna and the surface under the vehicle which acts as the ground plane...

    "...There are a few pundits who are under the misguided belief, that running a braided bonding strap along the frame of a body-on-frame vehicle, bonded every few inches, will drastically improve the less than perfect ground plane a vehicle represents. It won't!...."

    The two pertinent and inconsistent phrases from the quotes:

    "A vehicle is not a ground plane"

    "ground plane a vehicle represents"

    No wonder the nomenclature confusion. Even the experts struggle with it. Now I don't feel so bad. :)
     
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  5. Ridgeline

    Ridgeline Road Train Member

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    I use alan’s site as a central reference source so you guys can read details.
     
    jdchet Thanks this.
  6. craig_sez

    craig_sez Road Train Member

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    10" alumium..I took it off tried 3 new 7ft skip shooters and my 10k....The 102" on the riser im fully extended and analyzer says i need to go longer...My skip shooters its the opposite..
    I even tried my old ss and cut off about an inch or two of the coiled wire reattached the tip of wire to tip of ant and used nail in the ant head to tune a lil better..
    I remember before adding about 6" of a whip to make same ant work on previous truck..
    Im missing something that i just dont understand/know about..
     
  7. jdchet

    jdchet Light Load Member

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    Maybe ditch the riser and start over?
    I think you might be chasing rabbits trying to improve your antenna system. My philosophy, as far as this, if it's decent to good leave it alone. Your never going to get it perfect due to the known issues regarding mobile installations. It's your time to spend regarding your quest, but much like trying to make a co-phase system work, is the "juice worth the squeeze"?
    Carry on Craig and I hope you get where you want to be!

    JD
     
  8. craig_sez

    craig_sez Road Train Member

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    Well if i had never gotten further with same basic set up i would agree..
    Cant ditch the riser cause i cjt the threaded end off the 102"...
    What weird is that i was able to almost match my 102 with my skip shooter ut now,noticeable diff..
     
  9. Meteorgray

    Meteorgray Heavy Load Member

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    Is the 10" riser a functional part of its RF electrical length? If not, perhaps the 102" stinger is a bit short for a true quarter-wave? The antenna analyzer should indicate the situation.
     
  10. jdchet

    jdchet Light Load Member

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    @craig_sez just a random thought...........Maybe you have TOO Many ground straps?
    I watched a couple of your Youtube vids and it looked like your antenna was in pretty good shape.
    When I was running a mail inserting machine years ago, a Pitney Bowes mechanic always stressed, when someone would look to adjust something to make it run better.......If it ain't broke, don't fix it!

    JD
     
  11. craig_sez

    craig_sez Road Train Member

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    Never have to many...
     
  12. craig_sez

    craig_sez Road Train Member

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    Yeap..Acts basicially like the mast of a coiled ant..I clipped it at the very end where threaded piece is attached to the whip..Whip is at full extention and its better on 40 than 1 by a good bit....Doesnt explain why my 10k has opposite issue and my 7ft skip shooters need to be trimmed(the coiled wire inside the ant)with nail down to min setting..
    Funny to now that i calibrated my analyzer with a open,short,load that my analyzer shows a low swr and meter on radio shows a higher swr..I suspect i may have a coax issue and or radio meter is off..
    Not been feelin so great this week(took vaca)and wanted to give truck a good ole bath n polish and do some bonding n such but no such luck....Also got family commin and had to tidy up so no desire with humidity to go ojtside in the sun..
     
    Meteorgray Thanks this.
  13. Meteorgray

    Meteorgray Heavy Load Member

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    Quote: "...I clipped it at the very end where threaded piece is attached to the whip..Whip is at full extention and its better on 40 than 1 by a good bit...."


    It's my understanding that the RF electrical effect starts at where the antenna's conductive wire is connected to the stinger, and the electrical effect extends to the tip of the antenna, all of which determines its electrical length in regards to resonance and, less precisely, its SWR.

    The reason I asked the questions is that any object serving as the point that the antenna stinger is screwed onto and isolated from, which could be a riser pipe, is not included in this electrical length.

    One way to interpret your quote above is that the 102" stinger is screwed onto an insulated 10" riser pipe, and that the wire begins at that threaded junction point. If this is the case, then the antenna is electrically at 102", which is shy of a quarter-wave and thus would be better suited for channel 40 than channel 1 because it's too short and should be lengthened by about six inches or so.

    But, I probably have misinterpreted the situation and, if so, apologies in advance :)
     
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