Hey all,


I am trying to get my Cobra 75WX ST CB radio installed with a Firestik NGP antenna mounted to a teraflex mount on the spare tire carrier. On one of Firestik's tutorials they mentioned that if mounting on the tailgate, the bushings of the swing arms make it tough to ground. I read around the forums and know it's possible, but I didn't want to bother so I went with the NGP.


But, after getting the Teraflex mount on the rear tire carrier and running the NGP coax cable through the back tailgate, up the right side roll cage bar, and connecting to the radio behind the glove box, I cannot get the SWR tuned. The antenna is as short as it can be, and channel 1 = 2.4, 19 = 1.6, and 40 = 3.0. I have the insulated shoulder washers on top and bottom of the mount between the antenna and the coax ring terminal.


I attached pictures of the antenna side of the install. If anybody has any pointers I'd really appreciate it!

 

There's a few threads in regards to tailgate bonding. I don't think anyone on here has got an 11 meter antenna without doing it.

 

From looking at the pics you have only connected your center conductor of the coax. You did that correctly but you also need to connect the coax shield to one of the bolts of the mounting bracket on the tailgate and also bond the tailgate to the frame with a braided ground strap to complete the Installation. Then tune it up with a good SWR meter.

 

I see two possible problems. First is the spring has added length to your antenna. So before you had to cut it, it was the proper length for frequencies numerically higher than the CB band. If you ditched the spring, you would now be too short. Second problem is the coax shield needs to be bonded to the ground at the antenna end. Believe it or not, that little center conductor and the crimp connection are radiating signal. You want to keep the radiation in the antenna. You should buy a proper cable with the correct ends for the application.

 

Personally I would ditch the NGP and use a standard mount and antenna. Fire stick is great by the way. You can bond the tailgate to the tub via a ground wire attached to the tailgate where the cable passes through and run it along the tailgate wiring. Ground to any convenient spot on the tub. I chose passenger side under the rear cover. If there is still an issue then bond the tub to the frame. Are you going to run with the spare tire in place? If so be aware of detuning of your antenna. The tire will block the radiated signal and create a SWR issue. It will really mess you up if you add an aftermarket bumper with tire carrier. All the metal will screw it up royal. Personal knowledge there.

 

The coax is installed correctly for a NO GROUND PLANE antenna. It only uses the center conductor!

Firestik offers this as a kit...is that how you purchased?

 

I recently had problems with my NGP firestik. I had high swr readings as well. After talking with Firestik and running through a bunch of troubleshooting. He asked me to test continuity between the base of the antenna (just below the shrink wrap and the tip of the antenna (the screw adjustment). He said it is rare but we had checked everything else. I had zero continuity! He said the wire must have got separated from the base or is broke somewhere under the shrink wrap. Sure enough I cut the shrink wrap near the base and the wire was not soldered to the base. I did try to re-solder it but it didn't hold.

I ended up buying a regular ground plane antenna and just ran a ground wire to the tub of jeep.