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So, if you remove the antenna from the mount, connect it to the coax cable and hold it by hand, what kind of SWR are you getting? If you're seeing good numbers like down in the 1.5 or less, something somewhere is grounding out.

In case you missed it, here is a diagram of how the stud should look like attached to the mount.

ant-mount.jpg
 
wayoflife said:
So, if you remove the antenna from the mount, connect it to the coax cable and hold it by hand, what kind of SWR are you getting? If you're seeing good numbers like down in the 1.5 or less, something somewhere is grounding out.

In case you missed it, here is a diagram of how the stud should look like attached to the mount.

View attachment 317667
Click to expand...

Will do this tomorrow before getting a new coax haha . Guess this is an easier way than going for the multimeter .

Will also get the tire off and scrape paint off bolts attaching the mount to the tailgate .

I’ve seen the diagram . Where should ground strap go ? I have it below the washer above the nylon right now


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danford.lau said:
Teraflex bracket is painted . I scraped off powder coating on the hose where antenna is mounted but didn’t do this with other bolts to tailgate yet ... figured the grounding strap would solve this ..

Ground is at control box in glovebox . Ground runs to battery


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Click to expand...

wayoflife said:
So, if you remove the antenna from the mount, connect it to the coax cable and hold it by hand, what kind of SWR are you getting? If you're seeing good numbers like down in the 1.5 or less, something somewhere is grounding out.

In case you missed it, here is a diagram of how the stud should look like attached to the mount.
Click to expand...

Eddie, would having the brain grounded to the battery create an issue? Since the antennae is mounted to the body, should the brain be as well?
 
danford.lau said:
I’ve seen the diagram . Where should ground strap go ? I have it below the washer above the nylon right now
Click to expand...

The strap is needed to ground the "tailgate" to the frame. It by itself isn't enough of a ground. You are NOT using it to ground the antenna.
 
TrailHunter said:
Eddie, would having the brain grounded to the battery create an issue? Since the antennae is mounted to the body, should the brain be as well?
Click to expand...

Assuming you're talking about the main unit that you install remotely, I don't think it would make a difference if it got grounded to the battery although, it really isn't needed. The main power lead really should be connected directly to the battery though as using a keyed source would give you noise in the line.
 
Sounds fun. Have a great time. I start a new job so I won't be able to join in. I enjoyed my first New Year's Kick Off in 2015. It was my first time to the Mojave. Maybe next year. Can't wait to see pictures.
 
Here is my current mount . Relocated the ground strap off the antenna . Now runs from a bolt connecting the mount to the tailgate through the hinge into a bolt inside the quartern panel trim inside the trunk . Scraped as much powder coating off both bolt hole and the antenna mounting hole as I could with a knife . With this setup, SWR is just slightly over 3 at both channels 1 and 40 .. ugh

IMG_0944.JPG

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Took antenna off the mount and just propped it up against the rear tire . Tested again and SWR was actually worse .

IMG_0943.JPG

What do y’all think ? Time to try a new coax ? Running out of ideas


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danford.lau said:
Will do this tomorrow before getting a new coax haha . Guess this is an easier way than going for the multimeter .

Will also get the tire off and scrape paint off bolts attaching the mount to the tailgate .

I’ve seen the diagram . Where should ground strap go ? I have it below the washer above the nylon right now


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Click to expand...

Ground the tailgate mounting bracket to a ground stud on the chassis of the jeep. A multimeter can be used to verify 0 ohms from chassis ground point to the outer sleeve of the antenna connector.
It isn't necessary to ground the Cobra 75 box separately - the black wire is connected to it internally.
20181228_103607.jpeg
I've found the Firestick antennas to be touchy to tune even when properly grounded. The plastic tip changes the loading and affects match significantly, so after you adjust the tuning screw out the tip on before checking the match. I used a ruler to keep track of the tuning screw length. Final tuning to the sweet spot was like +/- 1/4 turn.



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danford.lau said:
Here is my current mount . Relocated the ground strap off the antenna . Now runs from a bolt connecting the mount to the tailgate through the hinge into a bolt inside the quartern panel trim inside the trunk . Scraped as much powder coating off both bolt hole and the antenna mounting hole as I could with a knife . With this setup, SWR is just slightly over 3 at both channels 1 and 40 .. ugh


Took antenna off the mount and just propped it up against the rear tire . Tested again and SWR was actually worse .

What do y’all think ? Time to try a new coax ? Running out of ideas
Click to expand...

Your SWR was worse with the antenna propped up against the tire because it has no ground. YOU or someone else needs to be holding it as you would be the ground. If possible, I would try to run the ground strap to the frame - anywhere on it just for testing purposes if nothing else and I would bet that you get a better SWR.
 
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Also your match will be shit if you're touching the antenna or within a foot or so of it while testing.

Verify the mount is 0 ohms to chassis ground point.

Check you match with Jeep parked in a clear area with no one near by the antenna.

Make small adjustments to the tuning screw and replace the plastic tip before rechecking the match.

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wayoflife said:
Your SWR was worse with the antenna propped up against the tire because it has no ground. YOU or someone else needs to be holding it as you would be the ground. If possible, I would try to run the ground strap to the frame - anywhere on it just for testing purposes if nothing else and I would bet that you get a better SWR.
Click to expand...

Will try it again with someone holding .

Will either of these 2 locations work for ground ?

IMG_0949.JPG
IMG_0948.JPG


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