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CB Anntenna Question

Discussion in 'Communication (CB | GPS | HAM)' started by Drey, Nov 11, 2006.

  1. Drey

    Drey 3/4 ton status

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    I mounted my antenna to the Plastic ABS or whatever it is roof rack on my 96 Blazer. Do I need to Ground it somehow? If I need to what will I have damaged on my CB? Ive ran it about 6 months now without it grounded and just recently someone told me I needed to have it ground. I dont have my CB on all the time, but I have used it a bit.
     
  2. W7NB

    W7NB 1/2 ton status

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    Proper grounding of you antenna.

    In order for most antennas to operate in their designed manner, they need a "ground" or what we would call a counterpoise to work against. In ultra simple terms, it somewhat like only hooking up the plus side of a jumper cable to the battery. I the case of an antenna though, the rf energy will flow back down to the radio via the outside shield or "ground" side of the antenna wire, possibly causing damage to the radio and certainly not working at it's peak efficincy.

    If you are using a mirror mount to clamp the antenna to your roof rack, take a piece of braded wire and run it from the ground stud on the antenna to a good solid metal ground nearby - the closer the better. Soldier the ends onto the ground wire if you can - RF energy is picky and won't like anthing less then a perfect connection especially if it's been wet and grungy.

    After you get the antenna grounded, make sure to have someone check it with an SWR meter. You will be amazec what a difference properly tuning the antenna makes to the operation of your radio. If yod don't have a meter, find a local ham - almost all of us have testing gear for antennas.

    Hope this helps!:o
     
  3. cbbr

    cbbr 1 ton status GMOTM Winner

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    two quesions - 1) does it work like you have it now and 2) what kind of antenna?
     
  4. Drey

    Drey 3/4 ton status

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    Yes it works the way it is right now. It is a way old Kraco I think. One of the trunk mount styles. I have it mounted to a thin metal plate which I have straped to the roofrack with some metal straps
     
  5. cbbr

    cbbr 1 ton status GMOTM Winner

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    Mine didn't work very well at all until I ran aditional grounding sraps, and mine is mounted through the roof. Normally you need to ground the antenna to reduce the SWR. Was the antenna a mag mount?
     
  6. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    On an antenna thats not on a huge metal panel , yes I would ground it . However most CB antennas are not . I have never seen a magnet mount , gutter mount , bumper mount , mirror mount , or any other CB antenna with a seperate wire to ground .

    My NMO mount for my amatuer antenna is grounded though .
     
  7. W7NB

    W7NB 1/2 ton status

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    Antenna mounting issues.

    For the most part, any resonant antenna "works", it's an issue of effiicency. If only 50% of the transmit power is being radiated from the antenna and the other 50% is going back into the coax you only are getting 2 watts effective radiated power - and of course people don't "hear" you as well. Proper placement of the antenna and grounding will give better performance, allowing the same 5/8 wave antenna to have an ERP of 10 watts, assuming it's a 5 dB gain antenna. Lets see, 2 watts or 10 watts, hmm...

    Magnet mount antennas use induction to provide their counterpoise (or ground if you will). They are not quite as good as the NMO mount in the middle of the roof someone mentioned but are still very usefull with the right placement.

    First generation folks with the fiberglass roof have 2 choices for a truly effective antenna. Either use a fender mount or body mount ala ball mount on the side of the rig, or buy one of the marine "No ground needed" antennas and mount it on the top.

    I know this is kinda long haired stuff, but the antenna is really the most important part of the system. Even the best radio sucks with a poor antenna. Remember, and open differential "works" too, but how much better is a locker?
     

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