Cobra 75 WX + 4' Firestik NGP - Mediocre SWR - Where-to Next?

Hi all,

I installed a Cobra 75 this afternoon to replace a remote face Cobra 29 which was a fun project but didn't really perform as I had hoped. A few weeks ago my NGP coax wire was damaged, so I beefed up my mount and elected to repair the wire. At that point I didn't realize you couldn't cut the NGP coax wire. So to make a long story short, I have a new coax wire and a new radio, along with an existing 4' Firestik NGP antenna.

I purchased a SWR meter and I notice that no matter what I try with my tuning, I ultimately keep ending up with a SWR of approx 2.2-2.3 on Channels 1 and 40, with a reading of approximately 1.5-1.6 on Channel 19. While this isn't an outlandish number, it's not particularly good, either and I'm wondering if there's any areas I can look for improvements. My antenna is the Firestik NGP with a spring and fold down mount.

So far, I've done the following:

- Adjusted the antenna tip, and I need to do this further.
- My mount is in the bed, using the Firestik 3-way mount. It is approximately 1/2 down the rail, behind my light bar foot mount.
- I have continuity between the mounting stud and the spring, but no continuity between the mounting stud and the mount itself. This compares favorably with the Firestik diagram.
- Coax is run loosely through the truck with only a single noticeable bend over the bed rail and down into the rail system.
- Cobra unit is grounded via a ring terminal and seat bolt, no paint is scraped off.
- Cobra unit is not yet secured to the truck. I notice a slight change in SWR when the unit is moved around, so I plan on securing it tomorrow morning.

Future Plans.
- Run a ground wire from the Cobra metal control box to the shifter bolt after scraping the paint away and coating with electrolytic grease.
- Scrape paint away from seat bolt mount and coat with electrolytic grease
- Mount metal Cobra box in front of shifter with 3M double sided tape
- ???

I'm not really sure if I can improve upon what I have, although I am hopeful grounding the Cobra metal brain unit will yield some improvement. From what I've been reading a SWR of 2.2 on a NGP antenna may be as good as it gets. One article from Firestik in particular talks about the dip in SWR at the middle of the range showing that you have hit the limits of the antenna. I do not desire to convert to a non-NGP antenna as for the amount of usage I will actually see, it's not worth the investment. In addition, I like where my mount currently sits so I'd prefer to move that.

Thoughts?