Another tuning question

Do NOT cut anything yet. If you are at 1.5 and 1.6 you are close. IF it truly is 5 and 6 you have some big time grounding issues and no amount of cutting will help

 

Yup, I don't know much but ya need to get it way down, probably closer to 2 before cutting. Hopefully someone with more knowledge will chime in. Just tryin to keep ya from ruining a whip right away.

 

Still a grounding problem. And it is probably rf ground and not electrical ground. You may have to do some bonding to get it where it needs to be. Braided bonding straps are best. You can use coax (has a braid in it.) Run short runs instead of one long wire. i.e. antenna mount to door, door to body, body to frame. Sometimes it can be a real challenge and same model trucks can be totally different.

 

My guess is that the problem is your antenna cable, maybe shorted or open. Use a ohm meter and check your end to end making sure that the enter conductor and the shield are continuous, but not shorting to each other, if that's good check the pl259 to make sure it is soldered properly.

This needs to be confirmed before your needing to get into adding grounds. ground loops cause a whole new set of problems.

 

Listen to Mike5511 because he nailed it. Anytime your SWR reading on an external meter is 3 or higher, you should be thinking bad antenna ground plane.
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.What you need to do is interconnect the large metal components of the truck for RF [radio frequency] purposes into one large antenna ground plane. Run short lengths of braided ground straps. First, from the antenna mount to the door. Next, A separate strap from a bolt that mounts the door to the hinge. The other end of the ground strap goes to the bolt that mounts the door hinge to the cab frame. Finally, from the cab frame to the chassis frame.
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.As Mike correctly stated, keep all straps short in length. Otherwise, a long strap could act as another antenna. Which is exactly why running a strap from the antenna mount directly to the battery is a bad idea.

 

Mike has a good teacher..................