SWR

Discussion in 'CB Radio Forum' started by RetiredVOMA, Jul 13, 2018.

  1. Ridgeline

    Ridgeline Road Train Member

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    Yeah I get what Gadfly is saying and where others are coming from but it comes to taking the least problematic issue and eliminating it. The grounding may be one solution for the issue but shouldn't we have to assume that the antenna isn't tuned to begin with so that would be the first step, right?
     
    rabbiporkchop Thanks this.
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  3. RetiredVOMA

    RetiredVOMA Bobtail Member

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    I’ve tried 2 different Firestik’s so I would guess the antenna is not the issue. Would 12’ versus 18’ of coax create that much of an issue.
     
  4. skellr

    skellr Road Train Member

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    In therory it could. Thats how NGP antennas get a "ground" is by using a boat-load of coax.
    I don't think it's going to help enough to be worth the time. That's how NGP antennas work, they use a boat-load of coax (20'+ or so) as a "ground", NGP antennas have a notoriously short range.

    Think of it as standing next to a lake. You can skip a rock further across the water than you could throw the rock. You need a ground plane to skip the signal. You are looking for any horizontal metal you can find like the frame or even exhaust pipe.
     
  5. rabbiporkchop

    rabbiporkchop Road Train Member

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    It's not so much an issue as an illusion.
    Using a device as crude as an SWR meter to determine your problem when you're not even in the ballpark makes things very difficult.
    An swr meter is completely useless when you're not even in the ballpark.
    An antenna analyzer would be the best tool for troubleshooting this scenario.
     
  6. Ridgeline

    Ridgeline Road Train Member

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    Boy ... wow ... it has to be a radio dysfunction day.
     
  7. Night Stalker10

    Night Stalker10 Road Train Member

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    As far as the side mounts go, I wouldn't think it matters what brand it is. I don't think there's any difference in them as far as functionality goes, at least none that I know of. Tensleep is right, you need a NGP (no ground plane antenna system. With a NGP antenna system it's very important to have the correct antenna and length of coax. What I mean is the NGP antennas usually have a yellow band on the bottom of the antenna (firestik brand anyway). The coax has to be a certain length since it's part of the antenna system. I noticed on Amazon the coax length for the Workman psm-2 mount is only 12 foot long. That probably won't work with a NGP antenna, unless you just bought the mount only. Usually the coax length is 17 or 18 feet depending on manufacture. Here's a link that I came across explaining the NGP system. you don't hook up the ground side of the coax since it's part of the antenna system.

    Template - Tech Doc

    I assume you have been trying to adjust your antenna length to bring the SWR down? If so, has the SWR reading on your meter changed any? Like Ridgeline said, if you know anyone with an antenna analyzer, it sure makes it easier to tune your antenna system.
     
  8. Night Stalker10

    Night Stalker10 Road Train Member

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    Guess I probably just added to the radio dysfunction day.:rolleyes:
     
  9. wolverine11

    wolverine11 Road Train Member

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    September 1st,2018, Michigan vs Notre ####, Southbend In, cant wait Im counting it down. Sorry guys off topic just wanted to get Ridgeline thinking about something else.
     
  10. Night Stalker10

    Night Stalker10 Road Train Member

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    Hee Hee, good one.
     
  11. Gadfly

    Gadfly Medium Load Member

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    Tnx! People don't realize there is a difference in RF ground and electrical ground. Remember: this is the reason why base antennas have radials. They are the "other" part of the antenna itself. Depending on the length of any bonding straps, you could also unwittingly create another problem: resonant grounds. These can cause RF to travel along these paths with all sorts of unwanted consequences. They can cause mysterious squeals, grunts, groans, and "ghostly" happenings such as windshield wipers coming on when you transmit. Or getting "bit" when you touch the mike with your lip (OUCH!), and things getting warm to the touch.

    This isn't common, but could happen depending on how long the path from the mount to the chassis is. And it wouldn't hurt to bond the frame AND extend a wire over the cab/body of the truck. Ya never know!
     
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