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Thread: SWR is extreamly high....please help

  1. #1
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    SWR is extreamly high....please help

    Been is CB radios for 45 years now. Never had a problem like this one.
    New President BILL CB radio
    NEW Wilson Flex tunable 4' antenna
    New Rear body antenna mount for Jeep.
    My SWR is so high it pegs the needle. I have tried several ways to mount the antenna with and without the Wilson impedance matching wire added/removed. No change in SWR readings.
    The mount has been ohmed out for resistance back to the Jeep battery and after going through about 35 feet of wiring reads 6 ohms for ground.
    The SWR meter is clearly marked ANT and TRANS and is hooked up properly.( I have not tried to swap the two coax cables)
    The antenna reads .001 ohms through itself
    My coax to the antenna reads .001 ohms through 18' of coax.
    Ground to the radio or the coax shield reads .001 ohm to ground.
    "tuning" the tip does not help.
    Grounding the secondary Wilson wire does not help.
    Moving the Jeep to the middle of nowhere does not help.
    I'm at a complete loss as to how to drop my SWR down to safe operating levels.
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    The mount as it was to be used. All of the paint where ground is needed has been removed.

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    The antenna has the same very high SWR reading no matter if the secondary antenna wire is used or not.
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    Reading through antenna signal to ground. The antenna is not shorted out.
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    Reading from antenna ground all the way to the battery and back through the wiring of the trailer hitch power. A distance of more than 35 feet.
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    Zero SWR meter ( tried other SWR meters get same results from all meters) Camera is slightly off set but needle is sitting on CAL.
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    SWR is so high I'm afraid I will damage the finals.
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    Reading through the antenna base, 18' of coax and the SWR meter ( secondary wire disconnected)
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    Reading through the whole antenna, 18' of coax and the SWR meter.
    Last edited by Rapidrob; 12-20-2020 at 01:29 PM.

  2. #2
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    I see a wound boil on the antenna, near the base. That can cause the high SWR. Swap for one with the load coil closer to the top of the antenna. That, or move the mount higher on the body of the vehicle.

  3. #3
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    So you think the antenna is the problem?

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    Honestly the first thing I would do would be to try a different brand of antenna. Specifically, look for one that is branded as a top loaded antenna and try that.

    How high is the tip of this antenna compared to the height of the roof of the vehicle? It should clear the vehicle by at least 2 feet or you will have problems. Antennas don't like being close to metal, such as the body of a vehicle, but certain parts of the antenna are more sensitive to this than others. This is the reason, as was stated above, that a coil should be higher than the roof of the vehicle.

    Quote Originally Posted by mjd420nova View Post
    I see a wound boil on the antenna, near the base. That can cause the high SWR. Swap for one with the load coil closer to the top of the antenna. That, or move the mount higher on the body of the vehicle.
    I haven't opened one of these antensas up, however, that small coil at the antenna's base? I don't think that is a base load. It appears to me to be more of a shunt coil, and is likely paired with that ground wire as an impedance matching circuit. There would be no other reason I can think of to have a wire go from an antenna like this and attach to ground.


    The DB

  5. #5
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    The antenna is 2 1/2 feet above the roof line of the Jeep.
    I was able to get the SWR down to 1:5 which is very poor and may damage the transmitter. I will not use the radio until I can get it down to 1:1.2 or 1.3

  6. #6
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    I'm wondering if I should go to a roof magnetic mount using the same antenna? It will give me a much larger ground plane.

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    While there may be better I have always used mag. mount antennas in the center of the roof with success.Lot of it depends on your demands from your mobile system.

  8. The Following User Says Thank You to whiteastro For This Useful Post:

    BOOTY MONSTER (12-27-2020)

  9. #8
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    I ordered a heavy duty Mag Mount for the Jeep. I'll use the same antenna which has good reviews.
    Thanks for the replies guys.

  10. #9
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    What is that antenna? Not sure why it has that wire running out the bottom like that, unless maybe it's some kind of no-ground antenna...

    If it were me, I would get a different antenna, and since your thinking of a roof mounted magnet mount, check out the Sirio Performer 5000 with a magnet mount...


  11. #10
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    It is a Wilson 4' FLEX 5/8 wave. It has good reviews and can be bent 180 degrees without braking.
    I wanted it for off-road riding and prevent damage to the antenna without having to use a "spring".
    The wire is for tuning but in my case does not work well due to where the antenna is mounted now.
    Most folks cut it off as it is not needed in most installations.

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