I installed the JK ultra mount over a month ago and have been really satisfied with how the mount is conceiled and how it retains a factory look to it. Just recently I've been getting some interference when talking on the CB and I recently checked my SWR and I can't get it below a 3 in the red zone on my SWR meter. Previously I could get it down to 2 but now with the top on it's at 3. I did discover that parts of the plastic in the license plate holder were somehow jamming into the coax cable causeing some creases in the cable but no tears or rips in the cable. I have since routed the cable differently in the licesnce plate holder. I also noticed that a significant amount of water and mud had made there way through the hole around the antenna into the license plate holder. I cleaned it out and my reception got a little better but the SWR is still above 3 on all channels. A friend of mine and I were driving down the interstate and I had trouble hearing him at around 2 miles! He could hear me fine for a lot further but I couldn't hear him. I have since put RTV silicone in the hole in order to seal it from getting water and mud.

Any ideas as to why my SWR might be so bad? I must also add that instead of the 4' Fire Fly that came with it I use a 3' Firestik II with the adjustable tip. It stays below the roofline and I like the way it looks. Before I put the top on I was also getting better SWR with the Firestik than I was with the Firefly. Should I replace the Coax cable with the creases in it?

 

Sounds like the antenna is not grounded good, becareful if it's not it could damage your transmitter.

 

The Ultramount kit I purchased included a new ground wire that grounds the antenna mount to the frame behind the rear driverside tire. This wire did get extremely muddy when the reception was getting bad. Don't know if this will affect it at all.

Thanks for the advice with the ohm meter. Where could I find one? What would be a good ground source when checking the cable at the CB end?

 

The antenna mount is not what needs to be grounded. It's the coax shield. No matter what sort of mount you have, you can easily run a ground wire to the portion of the nut under the mount and solder it on the nut. Not to the nut that you screw on, but to the nut portion that runs through the mount on the bottom. This is the absolute best way to assure a ground. Doing it this way assures that no matter what, your coax shield is grounded, and not the mount. Grounding the mount is absolutely useless unless the coax shield is grounded to it. Remember, ground always takes the path of least resistance. If that path is straight off the coax shield to ground, there's NO other way. Over time, dirt, debris and rust can get between the antenna fitting and mount and between the mount and whatever it bolts to. Running the ground wire directly to the coax shield solves all these problems. Don't make the mistake and use an eyelet on the antenna fitting. If the eyelet contacts the portion that goes through the mount, that will be a direct short. It needs to be soldered to the male part of the antenna fitting that comes through the bottom of the mount.