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Old 09-28-2012, 02:37 PM   #1
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Cant get an SWR reading below 3

Hi
I just installed a 3' firestik firefly on a 2012 JK, and I'm not able to get the SWR below 3. Here is what I have done.

I used a Terraflex tailgate bracket. My ground wasn't all that great since it was on a tailgate.
So, I took a 12 ga wire and found a great ground by using the the tie down bracket in the back of the jeep, and also tapping into the sheet metal inside the back door near the wheel well. I ran the wire to my Terraflex bracket. I still had some less than perfect readings so I disassembled, sanded-ground etc, and put it all back together. Things seemed perfect.
I even did a voltage drop test where I got .001

I took the jeep to a field and tried again. I am able to get 1 & 40 almost dead on, but the problem is that the reading is at 3 on the SWR. I was able to get ch. 40 to 2.5 ish but ch 1 was climbing above 3.

What am I missing? It can't be a ground issue. OH,,, when I tested my coax with my multimeter for resistance, I was getting .5 Is that enough to destroy my SWR reading? With all of my other ground test I'm getting close to .1

Needless to say ---->

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Old 09-29-2012, 03:13 PM   #2
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Here is a bit of information that may help me with my tuning.

On the firestik, with the adjustment screw low, I am getting 1.2 on ch. 40 and
well over 3 on ch. 1
So I raise the screw and the numbers slowly come together. This morning I tried to tune it again and was able to get the numbers to match at 2.75.

Am I doing something wrong? 1.2 is sweet,,, why is ch 1 way off from ch 40?

Not sure if this info helps but I thought I'd toss it out there.

Dave

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Old 09-29-2012, 03:29 PM   #3
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Your antenna is too long.
Is there anything in the instructions about shortening the antenna? You'll want the screw all the way in. Are there any extra washers under the antenna that are adding to the length?
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Old 09-29-2012, 10:04 PM   #4
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Hi Sparky

No instructions on lowering the antenna, and no washers to remove.
Only the adjusting screw at the top.

What now? I'm stumped.
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Old 09-30-2012, 09:29 AM   #5
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Quote:
Originally Posted by sparky View Post
Your antenna is too long.
Is there anything in the instructions about shortening the antenna? You'll want the screw all the way in. Are there any extra washers under the antenna that are adding to the length?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This came from the sticky on how to use an swr. According to this, my antenna is too short.
I got 1.2 on ch40 and 3+ on ch1.

If the SWR is lower on channel 1 than channel 40, your antenna/whip is too long. If the SWR is higher on channel 1 than channel 40, your antenna/whip is too short.
Adjust your antenna in ¼ inch increments. Some antennas have a set screw that allows you to adjust the height of the whip and others must have some of the whip cut or ground off to adjust the SWR. Many of the whips are stainless steel and very hard to cut. A hacksaw, cutoff wheel, or bolt cutters will be necessary to cut these antennas.
After you make an adjustment, repeat steps 5 through 8 until your SWR is the same at both channel 1 and channel 40.
The goal is to get the lowest SWR possible. If your SWR is below 2.1:1 you are ok, 1.5:1 or less is what I would recommend . If you have or plan on getting an amp, you need an SWR of 1.3:1 or less. If you have tuned the antenna but still have a high SWR reading, you may try moving the antenna to another location on the vehicle or you may need to add ground straps to the vehicle for better bonding. Grounding & bonding is dicussed in another thread.
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Old 09-30-2012, 03:35 PM   #6
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OK, I had someting turned around.
In that case can you add any washers to the bottom of the antenna to make it longer. Plus get the screw all the way out.
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Old 09-30-2012, 09:05 PM   #7
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Quote:
Originally Posted by sparky
OK, I had someting turned around.
In that case can you add any washers to the bottom of the antenna to make it longer. Plus get the screw all the way out.
I'm thinking that I would be wise to get a spring.
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Old 09-30-2012, 09:09 PM   #8
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That is a crap mount. Check out ArizonaRockyRoad.com for a real mount. Up high, no need to run a ground wire.
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Old 09-30-2012, 10:37 PM   #9
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Ok. I'll bite.

Why does everything need a ground except this?
I'm definitely interested.
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Old 10-01-2012, 08:56 AM   #10
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Good question! I am no expert by any means, but the stud grounds to the large steel mast, and that seems to be enough. You just need to grind paint off from the underside of the top part. I have a 1.2.1 SWR even with a spring (must have) and quick disconnect. Plus it gets the base of the antenna above the rim of the spare. Order one, made in USA by a dude in AZ.



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Old 10-01-2012, 09:24 AM   #11
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What bothers me is that I can take my multimeter and check the ground at the end of the coax and get .1 That is almost a perfect reading. I can't see that will change by going to the Rocky mount. There is something else going wrong.
I agree that getting the base of the antenna above the tire is a really good thing.

Someone suggested soldering a jumper from the ground wire that I ran to my mount, straight to the threaded collar on the end of the coax just to insure the ground is good.
It can't hurt, and will only take a few minutes while I keep trying to get this mess fixed.
I will add a spring today too. If I can find one. Even Radio Shack got rid of their CB stuff.

I will be adding a ground strap to the tail gate as soon as I can find one.
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Old 10-01-2012, 12:59 PM   #12
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The spring will get you the extra length. Also consider a quick disconnect which will let you remove the antenna if you want to.
It's another option that will add to length.
Don't do both, you will end up too long. Decide if you want flex or quick removal.
Radio Shack is useless anymore for any communication gear (except cellphones), you need a CB shop, truck stop, or go online.
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Old 10-01-2012, 05:11 PM   #13
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Quote:
Originally Posted by sparky View Post
The spring will get you the extra length. Also consider a quick disconnect which will let you remove the antenna if you want to.
It's another option that will add to length.
Don't do both, you will end up too long. Decide if you want flex or quick removal.
Radio Shack is useless anymore for any communication gear (except cellphones), you need a CB shop, truck stop, or go online.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I just spoke to a tech at Firestik. He had me try a couple of things that I haven't done yet, including hooking up a set of jumper cables from my frame to the collar of my coax. No change what so ever.
He told me that the 3 footer won't work on my jeep, that I need a 4 footer.

WTF, it seems to work just fine on other jeeps.
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Old 10-01-2012, 07:37 PM   #14
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Quote:
Originally Posted by sparky
The spring will get you the extra length. Also consider a quick disconnect which will let you remove the antenna if you want to.
It's another option that will add to length.
Don't do both, you will end up too long. Decide if you want flex or quick removal.
Radio Shack is useless anymore for any communication gear (except cellphones), you need a CB shop, truck stop, or go online.
^^^^^^

Side note, after the attitude I got from the high school kid working at radio shack a few months ago, I gave him a little history note about how folks in the 30s had a really cool habit, building radios. In their shacks. From parts they bought. Then I asked him where radio shack came from, he said he didnt know. HA!
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Old 10-01-2012, 08:11 PM   #15
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Fireslayer where are you located? I'd be happy help you work it out i lf you were anywhere reasonably close.
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Old 10-01-2012, 08:58 PM   #16
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Originally Posted by Iceman
Fireslayer where are you located? I'd be happy help you work it out i lf you were anywhere reasonably close.
Southern California. Thanks for your offer, but we are more than a few miles apart.

I'll grab a spring and see if that helps
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Old 10-02-2012, 05:45 AM   #17
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Quote:
Originally Posted by Fireslayer

Southern California. Thanks for your offer, but we are more than a few miles apart.

I'll grab a spring and see if that helps
Yeah dont think I can swing airfare right now lol. I'll do what I can over the forum and pm. Keep me posted ok n whats going on.
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Old 10-02-2012, 07:31 AM   #18
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Yeah dont think I can swing airfare right now lol. I'll do what I can over the forum and pm. Keep me posted ok n whats going on.
I have been under the impression that it was a ground issue, so I was planning on adding a ground strap to the tailgate.
I spoke to the tech at Firestik and he had me hook my jumper cables to the collar at the antenna "stud" (bottom part). I did and there was no change. The numbers came together about 2.75
He said that the ground isn't the issue.

Looks like I will add a spring and if that doesn't work I'll do what he said to do. Get a longer antenna. He also made the comment that the newer jeeps are a pain when it comes to grounding.

dave
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Old 10-02-2012, 06:23 PM   #19
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Seems to be a groundplane issue, not electrical ground. Adding length should compensate for the difference.

There is very little groundplane when mounting an antenna on the back of a Jeep. Thats what makes em so hard, and why height is so crucial.
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Old 10-04-2012, 06:22 PM   #20
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Having same issue.

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That is my back mount. SWR is off the charts
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Old 10-04-2012, 07:02 PM   #21
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Originally Posted by AU95
Having same issue.

That is my back mount. SWR is off the charts
Is that stud insulated from contact on top of the mount by a nonconductive washer?

Doesnt look like it, which is a dead short, and will give you damaging swr. The bottom part that the cable screws on should be grounded, everything above the mount should NOT be grounded.

If it were a lug style stud, neither side would ground.
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Old 10-04-2012, 09:00 PM   #22
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Quote:
Originally Posted by BlueRidgeYJ

Is that stud insulated from contact on top of the mount by a nonconductive washer?

Doesnt look like it, which is a dead short, and will give you damaging swr. The bottom part that the cable screws on should be grounded, everything above the mount should NOT be grounded.

If it were a lug style stud, neither side would ground.
Hey BlueRidge - so where should I add a washer? And what do you mean by nonconductive? It's a stock K4A mount. Should I ground it on the stud instead of grounding the mount?
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Old 10-04-2012, 09:09 PM   #23
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With a k4a, the mount should be grounded by cable (or the tailgate its attached to IF it is conducting well), and by contact with the mount the bottom (beneath the mount portion) of the stud and the coax collar (sheilding) will be grounded.

Directly on top of the mount, where the stud attaches to it, there needs to be a nylon or other not-letting-electricity-through-it washer. You can make it out of wood if ya really wanted, but nylon is easiest. Shouldve come with the mount? Little white washer, feels like plastic. This insulates the antenna mast and threads from grounding at the mount connection.

If you dont have one, any hardware store will for less than 1$.

Other than that your grounding/connections appear OK, from what I can see. Over 3 swr is usually a short in something.
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Old 10-04-2012, 09:24 PM   #24
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Quote:
Originally Posted by BlueRidgeYJ
With a k4a, the mount should be grounded by cable (or the tailgate its attached to IF it is conducting well), and by contact with the mount the bottom (beneath the mount portion) of the stud and the coax collar (sheilding) will be grounded.

Directly on top of the mount, where the stud attaches to it, there needs to be a nylon or other not-letting-electricity-through-it washer. You can make it out of wood if ya really wanted, but nylon is easiest. Shouldve come with the mount? Little white washer, feels like plastic. This insulates the antenna mast and threads from grounding at the mount connection.

If you dont have one, any hardware store will for less than 1$.

Other than that your grounding/connections appear OK, from what I can see. Over 3 swr is usually a short in something.
Maybe it fell off. I accidentally ordered a k4 mount so I'll see if I can get a plastic washer.
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Old 10-04-2012, 09:45 PM   #25
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Quote:
Originally Posted by AU95

Maybe it fell off. I accidentally ordered a k4 mount so I'll see if I can get a plastic washer.
Meant to say I originally ordered a K4 so I still have that one and could use the washer from the K4 on the K4A?
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Old 10-06-2012, 08:44 PM   #26
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Yea any washer will work that is the right size and not metal. The k4 and k4a should be identical above the mount, so it should work fine. The k4 should have come with 2, but you only want one and it has to be above the mount with the k4a.
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Old 11-11-2012, 02:15 PM   #27
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I finally got it to work!

I have had so many little issues, and everything finally came together.
My ground was a bit of an issue, but even after cleaning everything up, I was still above 3 on the swr.
I have new coax, a 4' antenna (the three footer just wasn't cutting it) and I stopped trying to tune my antenna in the drivway. OH,,, and I removed the spring.
I figured that I was 20 feet from my house, but it was still a big deal.

I took my jeep to a field and I was able to get 1.5 on the swr. Both 1 and 40.
I'm pretty pleased with the results, but I still hate the 4 foot antenna. Oh well, I did what needed to be done.

I tried to get someone on I-5 to give me a radio check, but no one would give me the time of day. I'm probably only a half mile away so I know that I could reach the freeway. I'll get a buddy to give me a hand with that in the next few days.

Yeaaaay!

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