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Magnetic Antenna Question

TomGallopavo

TomGallopavo

New Member
Oct 21, 2024
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I'm new to CB so please forgive me. I am currently restoring my 1998 Dodge ram 2500 regular cab. I have turned my attention to the interior. The headliner needs to be recovered. The cb is mounted on the interior cab roof. The antenna is on the cab (center) and the cable runs straight back, then to the driver door, then along the top to the front center where the extra is wrapped in a figure 8. With the headliner removed I get less than 1.5 on the radio swr. If I put the headliner on it jumped up over 2. So I put a piece of foam underneath the figure 8 and that brought it down to 2ish with the headliner. I also have a 4 foot firestick I could moount on the headache rack. Should I splice the wire to make it shorter to remove the figure 8? Or is there something else I should try. Radio id a Galaxy 959 and the antenna is a Wilson little wil. Thank You!!!!
 

I am also using a mag mount and I bonded the coaxial ground to the car body for the ground plane. The RF ground is a must. Then I put a common mode choke about a 8 inches from my antenna. My coaxial is a lmr 240. The quality of antenna and coaxial has a lot of to do with your performance and the swrs as well. There's nothing wrong with wrapping your excess coax in a figure 8. CB radios are like ham radios only difference is the licensing requirement and the frequency. The frequencies of the CB and 10m ham are both considered high frequencies. When installing a CB just think like a licensed amateur radio operator.
 
IMG_20241021_120352019_HDR.jpgI wrapped tinned copper braid around the the ground of the coax and bolted to the lift bolt on my tailgate. Top picture is my SWR reading .There are no holes put into my roof and there are also no paint scratched off on my roof for ground.IMG_20241021_120329789.jpgIMG_20241021_120304284_HDR.jpg
 
Last edited:
9C1Driver said:
If it is a mag mount antenna there is no need to add a ground to the antenna. A mag-mount antenna is grounded through capacitive coupling between that magnet and the metal it's stuck to.
Click to expand...
The RF ground is established passively through magnetic coupling rather than an electrical connection. Electrically grounding an antenna provides a solid, low-resistance connection to the earth, which can help reduce noise, improve signal reception, and enhance the antenna's efficiency for both transmitting and receiving. However, if the ground plane is smaller than 5.5 inches in diameter, it will be ineffective in achieving the desired result. The purpose of the RF ground is to provide a reference plane for the antenna, effectively creating a mirror image of the radiated RF signal. This mirror helps the antenna optimize its transmission efficiency by providing a surface from which the RF energy can reflect and propagate, improving the radiation pattern and the overall effectiveness of the signal.
 

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