Cb setup tips. All help/info welcome

Discussion in 'CB Radio Forum' started by PotholeMcBounce, May 11, 2021.

  1. Lowboy456

    Lowboy456 Light Load Member

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    The SWR meter very closely agrees with what the analyzer says.
    Its just so much easier to see it all right there in front of you live with the analyzer.

    What I've learned with the analyzer would actually make me better on the traditional SWR meters or at least quicker than I was before.
    I had trouble with the affore mentioned antenna Road Pro 54 inch air coil becasue I took a 10 inch extension out of it. It was too tall for my job conditions and probably would have tuned easier with the stock setup.

    To draw a graph like what the Nano VNA H4 (is what I have) puts right in your face you'd about have to check every channel with the traditional SWR meter to find the V and chart it out.
    And then do it again for every antenna adjustment.
    With the nano it happens all live. Its one of those Wow! Moments for real!
    The SWR V is buried in there in every setup somewhere but hard to picture with the old school SWR meters.

    You'd be pretty darn close if you could get 1 and 40 perfectly matched with ch 20 reading low SWR for sure but man the hoops you have to jump through.


    The analyzer is faster! No flipping the switch and calibrating, flipping the switch again, keying the mike, flipping the channels, adjusting the antenna and doing all over and over and over and over again and one more time.... over again. Snip a little more. In my case I marked it and took it to a bench grinder. Stainless Steel doesn't clip to easily.

    You actually don't even have the radio hooked up at all just the analyzer strait to the antenna. The Nano VNA H4 covers all frequencies if memory serves so it has to be programmed for the target band.

    You place a cursor on your desired center of band frequency and adjust the antenna until it comes into the V.
    It does take a bit of study to get the Nano to that point, calibrated and like I have my 11 meter setup in memory so I don't have to set it up every single time.


    On a broad banded antenna like the Sirio gain master 5/8 base, it actually has a very low SWR across 3 bands 10, 11 and 12 meter.
    The Lil Wilson mag antenna that I use on my portable system it is so narrow banded that I can just barely get usable SWR on ch 1 and 40 although its low at ch 19 and 20 its closer to 2 to1 at ch1 and 40.
    Here is where I got my Nano VNA H4. They are out of stock now but available in many other places.
    NANOVNA NANOVNAH4
     
    Last edited: Jun 14, 2021
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  3. craig_sez

    craig_sez Road Train Member

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    Lol @ dog squeeze
     
  4. craig_sez

    craig_sez Road Train Member

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    Goin through your pick up roof(puc mount)is about the best deal you can do but tuning at 28000 then shunting down dont make sence to me..
    Whats the purpose of that??
    To get the best out of your ant assumeing all else is perfect or even 95% is to make ant resonant at your freq of choice,not frig all to do with swr..Yes it matters but not THAT much...
    From what i have learned is if your set up has lil to no resistance (45-50 ohms)and your resonance is dang near 0 then your golden..
    Never used or know about shunts but ma gut says its antenna/cb trickery cause your set up is off elsewhere..
     
  5. craig_sez

    craig_sez Road Train Member

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    Usually when loud they dont talk far or clear..Signs of a scatter box..
     
  6. craig_sez

    craig_sez Road Train Member

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    Analyzer is the same idea as a timeing light on the older style ignjtions n such..
    You can twist the dist cap so that car runs(inline swr meter) but if you want it degreed perfectly you need the timeing light(analyzer)....
    Just cause swr is good doesnt mean your ant is even close to a good r/x readings..If its other way around and your r and x #'s are good then its a good bet your swr is gonna be #### near dead on as well..
     
    jdchet Thanks this.
  7. Jimi Page

    Jimi Page Bobtail Member

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    May 18, 2021
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    Run your own separate coax and antenna could solve all the problems.
    Hook it to the mirror or behind the cab.
    Hook onto something grounded, or run a wire to it to ground it out on something else.
    The stock antennas and coax could be bad.
    Other drivers may have hooked up a high powered amplifier that ruined the wiring somewhere in the system or wire harness.
    Or it could just be the trailer you hook to has a short.
    Plug and unplug the light cord to see if their is a difference.
    With a good trailer the problem could disappear.
    All trial and error driver…
     
  8. Meteorgray

    Meteorgray Heavy Load Member

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    It is my impression that when adjusting CB antennas on vehicles, achieving a good SWR value generally also implies that the resonance with that antenna is good as well. IOW, a good SWR reading from a good SWR meter will generally allow for a well-adjusted antenna / coax combo.

    Of course, having an analyzer may be able to get you closer, but it is often overkill when used on vehicles and CB antennas.
     
    Last edited: Jun 15, 2021
  9. craig_sez

    craig_sez Road Train Member

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    Dont go behind the cab especially if you pull a reefer/dry box..Worst place evwr to mount an antenna..

    Define ground,where to and from and with what??
    Doubt the trl will be the issue..
     
  10. craig_sez

    craig_sez Road Train Member

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    Nope swr does nothing but make a radio happy..Swr gets you in the ballpark only..
    Impedences and resonance can be wayyyy off which is an antenna de tune and could make the radio work harder to get less performance..
    Sayin swr is good is like sayin you almost have a full tank of fuel but needle shows 1/4 tank..

     
    Last edited: Jun 15, 2021
  11. Jimi Page

    Jimi Page Bobtail Member

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    It’s easily done.
    I’ve done it on many different trucks I’ve drove over many years.
    (1) Rarely does the stock antennas and coax work well unless you have a newer truck.
    Clamping a single antenna mount to the drivers side metal mirror bracket, that’s attached to the metal door provides a instant grounding to the whole truck.
    If it’s a all plastic mirror setup, with nothing to clamp to…
    Then you’ll have no choice, but to clamp on to the bar or bracket behind the cab.
    Just keep the antenna tip below 13’ 6”.
    (2) Grounding: If the bracket is not mounted to metal, then run some electrical wire to it, stripped back a inch and pinch it into the antenna clamp.
    Run the wire over to a bolt that’s grounded into the frame or catwalk, loosen the bolt, wrap the stripped wire under it and tighten down.
    Or use a clamp, but it won’t ground thru paint, so you might need to scrap a little off.
    Thousands of drivers do it.
    (3) Different trailers can make a big difference in CB performance.
    It might work perfectly till…
    As soon as you hook the light cord to the trailer, you might hear your CB has static.
    Unhook it, it disappears.
    The trailer has a short from a butchered wiring job, for a marker light etc.
    You can try to find and fix it.
    Or just live with it till you drop the trailer.
    It’s as simple as that.
     
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