do you have a soft top? i installed my cb stuff with my top off just to make life easier and took a reading and got swr of around 1.1. then i put my hard top back on and spare tire and now get a reading between 1.4 and 1.5. just wondering if a hard top makes that big of a difference
Adding a hard top that is right next to the antenna (especially with a defroster in the rear window) will absolutely change what you get for SWR - but I wouldn't worry about 1.4. That's still better than a LOT of people ever get to.
As far as the tailgate being a good ground....when you get right down to it, there is very little on a Wrangler that is a truly good ground from an RF point of view. If you want good antenna performance, you can either mount it right in the middle of your hood, or line the inside of your hard top with a copper sheet, and always have your hard top on. Since both of those options are pretty ridiculous, most of us have decided that either a tailgate mount or a rear quarter panel mount will work fine. If you do go with a rear quarter panel mount, I'd suggest a big 'ol brass ball mount and a long, flexible antenna on a spring.