Mounting a CB antenna on the tailgate of a Jeep is not optimal by any means but many want it there for different reasons. Many variables can cause tuning issues. Grounding and antenna choice are the biggest issues. Always use a top loaded antenna such as a Wilson or Firestick that has the coil on the top. Antennas with coils on the bottom are too close to vertical metal that causes RF energy return to the transmitter (standing waves). Grounding the mount to the tailgate and grounding the tailgate to the body tub are key to getting the antenna to tune. It should also cure the intermittent problems for example one day you get an antenna warning light on the radio and on other days you don't. Even with the steps I will describe in this write up expect the SWR to be between 1.2:1 to 1.3:1. With alot of experience and trial and error a 1.1 is possible but I have only done that once. I usually get around 1.2.
Using a truck mirror mount this is how I built a budget mount for the rear of my JK.
The mount will make contact with the glass of a hard top if simply mounted on the brake light riser. I took a small amount of metal off of the curved section of the mount. Next remove the brake light from the riser. Cover the tailgate with towels to protect the paint. I used a 4inch angle grinder to cut a slit in the riser.
The mount will be bolted to the inside of the riser but the curved section will keep the mount from mounting flat.
Use the mount to determine the lower section to cut out.
Cut the relief hole and check for fit.
Make sure that there is enough play that you can level the mount with a small torpedo level with the vehicle on a level surface at least side to side. Front to back will be adjusted later.
Drill ONLY one hole and install the bolt. Only snug it down so you can rotate with a gentle tap.
Before drilling/installing the second bolt make sure the mount is level side to side. Failure to do this will most likely result in a leaning antenna. A small twist at the base will be exagerated by the antenna.
Finish the other two bolts and install the antenna on the base.
The mount should clear the glass. More clearance will be added later.
PROBLEM! Easy to solve.
Install 2-3 washers between the mount and the riser ONLY on the top two bolts.
Using a truck mirror mount this is how I built a budget mount for the rear of my JK.
The mount will make contact with the glass of a hard top if simply mounted on the brake light riser. I took a small amount of metal off of the curved section of the mount. Next remove the brake light from the riser. Cover the tailgate with towels to protect the paint. I used a 4inch angle grinder to cut a slit in the riser.
The mount will be bolted to the inside of the riser but the curved section will keep the mount from mounting flat.
Use the mount to determine the lower section to cut out.
Cut the relief hole and check for fit.
Make sure that there is enough play that you can level the mount with a small torpedo level with the vehicle on a level surface at least side to side. Front to back will be adjusted later.
Drill ONLY one hole and install the bolt. Only snug it down so you can rotate with a gentle tap.
Before drilling/installing the second bolt make sure the mount is level side to side. Failure to do this will most likely result in a leaning antenna. A small twist at the base will be exagerated by the antenna.
Finish the other two bolts and install the antenna on the base.
The mount should clear the glass. More clearance will be added later.
PROBLEM! Easy to solve.
Install 2-3 washers between the mount and the riser ONLY on the top two bolts.