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Should I add a grounding strap to the antenna mount.

Discussion in 'CB Antennas' started by CrashRecovery, Jun 30, 2020.

  1. CrashRecovery

    CrashRecovery Member

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    Oh dont worry about me shifting gears. I can clutch less shift anything with a manual transmission.
    If you are meaning I want to stick with what I got..... I never said I was opposed to it. I was trying to make sure what research I had done about antennas wasn't leading me astray. In a way it hadn't, the rest of the information hadn't revealed itself till now.
    The question I have now is this.....
    Inside or outside of the bed?


     
    Slowmover likes this.

  2. Slowmover

    Slowmover Elmer

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    Used as an analogy. You found out (are learning) it ain’t so hard to at least get the right pieces into the right places. I figured I owe it to myself to do this much, even if I bomb on the next parts. However hard that may be, I have a starting point.

    What money I spend is an investment in me (vehicles owned). Makes them and me “better”.

    My “better” radio rig years back captured a guy stranded on an oilfield road a ways off of the only highway.. Been there all night. Couldn’t walk out. I made the telephone calls he wanted (his had died) , and all was good.

    How you do it (how I do it or anyone else) starts to differ once the install begins.

    Motivation, comes into focus. If my experience is a guide, I’m glad some of the frustration you felt earlier has abated. There are threads here that died very quickly that had had similar starts.

    .
     
    #47 Slowmover, Jul 9, 2020
    Last edited: Jul 9, 2020
  3. CrashRecovery

    CrashRecovery Member

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    The reason I ask inside or outside is because of diagrams I've seen on how the signal radiates depending on where its mounted. Putting it on the passenger side rear, according to the pictures, basically forms a backwards D around my truck. If I was to mount it hanging off the bed towards edge of the road, how does that change the signal radiation and how the antenna sees the ground plane?
     
    Slowmover likes this.
  4. CrashRecovery

    CrashRecovery Member

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  5. Slowmover

    Slowmover Elmer

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  6. Slowmover

    Slowmover Elmer

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    Go back to the comments by M0GVZ. That’s VERY well-said.

    (It’s also why I recommended the example of a 49” NMO Larsen at roof center: performance and convenience. Convenience of constant use. Practical, in the best sense. Other options exist to meet those).

    Why not try both? First one direction and then the other?

    The blue koolaid guys are always telling me their pickups are special. (Until it’s time to work. Then have to slide a Dodge underneath to git ‘er dun). Maybe Ferds are CB special, too?

    The location drives the mount choices.

    .
     
    binrat likes this.
  7. CrashRecovery

    CrashRecovery Member

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    Slowmover, I'm really starting to hate you, in a good way. I'll send you a message through here to explain.
     
    Slowmover likes this.
  8. SIX-SHOOTER

    SIX-SHOOTER Sr. Member

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    In a Mobile setup you can't have to much ground.It won't hurt if you feel led to add more.
    I have never heard anyone say,I HAVE TO MUCH GROUND ON MY MOBILE ANTENNA. LOL

    SIX-SHOOTER
     
  9. Slowmover

    Slowmover Elmer

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    Really? Must be related to the most popular gravestone carving (I’m told), “This wouldn’t have happened if I’d stayed at the office longer hours”.

    I bought 60’ of 3/4”W woven copper braid and 150/ea of #10 5/8” stainless metal screws plus internal/external lock washers. (150) Selterm 4-AWG tinned copper lugs.

    Figured that (at a max length of 10”) the number of bonds could be up to (75) on just the pickup.

    Have already used some on the Peterbilt. Can see yet more uses. So would have gone ahead and bought 100’ to have gotten supply for (120) bonds as travel trailer and sons SUV yet to go with a little more thought.

    .
     
    SIX-SHOOTER likes this.
  10. Slowmover

    Slowmover Elmer

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    Funny this thread linked from another today.
    Just ran IH81N thru Hagerstown less than an hour ago.

    Now stuck at the manliest T/A Travel center in North America.
    (Address on John Wayne Drive.)

    A bunch of us having fun comparing that universal truck-driver irritation AKAthe Roger Beep” as we crossed the state line. Many types & tones. (No need to key down: just crank the amp and BIP him to perdition).

    Also known colloquially as the AFL Switch.
    (“Automated F______ Locator”)


    The vehicle-subject of this thread: got’er loud & proud as they say in CB-land?

    .
     
    #55 Slowmover, Sep 29, 2020
    Last edited: Sep 29, 2020
  11. CrashRecovery

    CrashRecovery Member

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    Funny as it is, I took a step back now that the light bar is mounted to the top of the rack. I temporally mounted the antenna off to the side on one of the bed rails and my swr went from 1.2 to 2.0 or 2.2 depending on how the whip was moving. I tried to adjust the length of the whip but i just made it worse. This weekend I'm thinking about finally biting the proverbial bullet and get the breadlove puck and everything mounted.
     
    Slowmover likes this.
  12. Slowmover

    Slowmover Elmer

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    Hell, I’m no farther along on mine.
    But, then, I only see it once a month for a few days.

    Now, screwing around with the one in the Peterbilt is a weekly thing.
    Whether it needs it or not.
     
    CrashRecovery likes this.
  13. Slowmover

    Slowmover Elmer

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    Received my Breedlove boat anchor awhile back. I take it out of the box every so often when home. Wondering, is today that day?
     
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  14. CrashRecovery

    CrashRecovery Member

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    Nope.... weather has been to shitty to spend time tearing the truck apart. However just for shits and grins, im trying a third brake light mount my buddy took off his truck before he sold it. I'm waiting on a new whip for a Wilson 1000 to see how that works. If that fixes my issue I'll run that till spring time when I can work outside with out loosing fingers to frostbite.
     
    Slowmover likes this.
  15. M0GVZ

    M0GVZ Sr. Member

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    Have you figured it out yet?

    Easiest way to work it out is like this.

    First of all remember we're dealing with electrical fields, electrons and the like. Remember that electricity and electrons and everything to do with electricity like to take the path of least resistance.

    Now imagine a flat circle on the ground, your antenna sticking up vertically out of the middle of it. Any part of that circle which is metal is going to have electrickeries flowing in it much better than any part of it that isn't. And any direction those electrickeries are flowing well is going to have a stronger signal than one that isn't.

    So if you have half of that circle in metal and half of it as bare ground those electrickeries are going to flow much better in the metal half than the ground because the bare ground is more lossy. So in this case you will transmit and receive signals stronger in the 180 degrees where there is metal under the antenna.

    So lets cut that half circle of metal to a quarter circle. Again still the electrickeries want to flow more in the direction of the bit that's metal so you end up with much stronger signals in the direction of the quarter of the circle covered by metal than the 3/4 covered by earth.

    And so it is with your vehicle. The disc still effectively exists even though there's nothing physically in one direction or the other if you mount the antenna on a side or in a corner. So in the case of sticking it in one corner of the vehicle as far as the antenna fields are concerned you've got that disc that only has 1/4 of it metal and 3/4 of it bare lossy ground, even though that ground is a few feet below it. And as we said the electrickeries prefer to flow in the direction there's metal. So if you've put it in the rear left corner you will transmit and receive signals much stronger towards the front right of the vehicle.

    And thanks to studies done on RF grounding we know the difference in signal strengths between the direction where there's ground wires at least a 1/4 wavelength long of this disc and just the lossy earth. That difference is 6dB or 2 S points on a CB S-meter.

    So now you know how to figure out which direction your antenna is going to favour depending on where you place it on the vehicle, it's going to be in the direction there's more vehicle.

    So how does this work putting it in the middle of the roof I hear you cry because obviously the vehicle is narrower than its length so the "groundplane disc" isn't round. And you'd be right that signals towards the back and front will be stronger than to the side but the signals towards the sides are still going to be stronger than if there was no metal under the antenna at all in those directions so it's more omnidirectional than any other option.
     
    ForestRunner98 and Slowmover like this.

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