Cant get a low SWR with my CB - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > General Tech Forums > Communications and Electronics

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 04-18-2013, 04:44 PM   #1
Jeeper
 
Giantxtc's Avatar
 
Join Date: Apr 2012
Posts: 40
Cant get a low SWR with my CB

I need some help. I bought a uniden pro 520xl and a lil Wilson 3ft magnet mount for my TJ. I have tried every imaginable place in the back and my swr meter is pegged out. I bought an L bracket and mounted in on tire mount, I tried mounting it behind the rear taillight., and I even tried just slapping it on the back bumper and nothing. I even tried grounding all of those locations. I thought it was a short and so I put out the mag antenna right in middle of hood and got 1.5 on both channels!!! Is my whip not long enough? Am I grounding it wrong. ( since it is a mag base I am attaching a ground wire to the L bracket the mag is on and then attaching it to frame. ) i have used a grounding strap and 10 gauge wire for grounding. do i just need to get a non mag antenna and start over?

Giantxtc is offline   Quote Quick Reply
Old 04-19-2013, 09:59 AM   #2
Jeeper
 
sparky's Avatar
 
Join Date: Oct 2009
Location: Phila
Posts: 1,760
Mag mount antennas get their signal ground through capacitive coupling of the base of the mount and the flat piece of steel they are sitting on. When you used your hood it worked correctly. Mag mounts are always a compromise, they can be an OK temporary antenna, but they don't have the efficiency of an installed system. Trying to use them without that broad flat piece of steel underneath is difficult.

I think it will be easier for you to go with a permanently attached antenna. A 3’ Firestick type with mounting and cable is not that expensive and will perform better.

sparky is offline   Quote Quick Reply
Old 04-19-2013, 10:56 AM   #3
Jeeper
 
Giantxtc's Avatar
 
Join Date: Apr 2012
Posts: 40
Thanks! Would I need a longer wip than 3ft if I attach it to the bumper? Does it matter whether the wip sticks out over the roofline?
Giantxtc is offline   Quote Quick Reply
Old 04-19-2013, 12:12 PM   #4
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 30,905
Images: 2
Probably the best/most popular way to mount an antenna is via a taillight mount like you can get from TeraFlex antenna mounts.

Then mount the antenna using an antenna mount like is shown below, which is a very solid popular way to mount a CB antenna. Just make sure to assemble it properly & place the white nylon insulated shoulder washer properly so it insulates the antenna from the mount.

Mounted via the below antenna mount on a tail light mount, a 2' antenna (like I use) works very well offroad. If you have enough clearance over the top or your Jeep, a 3' would be fine too. But for offroading, even a properly installed & tuned 2' antenna works fine, mine certainly does.

Two good antenna choices would be members of the Firestick FS series family which have a tunable tip for adjusting the SWR. The 2' would be the FS-2, the 3' would be the FS-3.
Attached Images
 
__________________
When you have a choice, buy American.

Jerry Bransford is online now   Quote Quick Reply
Old 04-20-2013, 04:55 PM   #5
Jeeper
 
Giantxtc's Avatar
 
Join Date: Apr 2012
Posts: 40
Thanks guys. One more thing. . As far as the taillight mount, how do you ground it? Where in the mount do you attach the ground and where on the body? Do you have to make a pure metal contact?
Giantxtc is offline   Quote Quick Reply
Old 04-20-2013, 09:38 PM   #6
Jeeper
 
lensam's Avatar
 
Join Date: Dec 2011
Location: Bridgeport CT
Posts: 265
The taillight mount is grounded by a screw that comes with the mount. You drill a small hole through the rear of the body( It killed me to do this but ya gotta do it ). You will need to sand the inside where you drilled through to get the proper ground. I got the stainless one from Quadratec because my whole set-up is SS. Heres the pic

http://www.wranglerforum.com/attachm...9&d=1364186573
__________________
2006 Rubicon Soft Top



It Looks Good From My House !!!
lensam is offline   Quote Quick Reply
Old 04-21-2013, 06:08 PM   #7
Supporting Member

WF Supporting Member
 
the Kolector's Avatar
 
Join Date: Apr 2011
Location: Louisville, Ky
Posts: 2,555
__________________
You Are The Result of 3.8 Billion Years of Evolutionary Success. Act Like It.
the Kolector is offline   Quote Quick Reply
Old 04-30-2013, 09:02 PM   #8
Jeeper
 
Giantxtc's Avatar
 
Join Date: Apr 2012
Posts: 40
Ok guys thanks for the advice. I got the connector and firestik fs 3 tunable tip and the teraflex taillight mount. I have it installed and tested swr. It's a little weird. Channel 1 is like 1.8. Channel 40 is 2.0 and channel 19 is like 1.4. What would cause that? I am perfectly content with anything below 2.0 but was wondering why the unusual swr between channels and if there is some trick to get swr lower. I did drill the bolt threw the body and sand the inside edge. Is that bolt enough to make a proper ground or should I use a grounding strap? If so were on the mount do I attach it?
Giantxtc is offline   Quote Quick Reply
Old 05-01-2013, 10:55 AM   #9
Jeeper
 
sparky's Avatar
 
Join Date: Oct 2009
Location: Phila
Posts: 1,760
That's normal and correct as is. Your antenna setup is really resonant on just one frequency. When you change frequency the SWR will change slightly. Some antennas are narrow banded, and it does not take much of a frequency change to get it out of the sweet spot.

Your setup is tuned for the middle of the band which is a good place to be. Yep, anything below 2 is fine. Leave it as is and enjoy.
sparky is offline   Quote Quick Reply
Old 05-01-2013, 11:12 AM   #10
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 30,905
Images: 2
Quote:
Originally Posted by sparky View Post
That's normal and correct as is. Your antenna setup is really resonant on just one frequency. When you change frequency the SWR will change slightly. Some antennas are narrow banded, and it does not take much of a frequency change to get it out of the sweet spot.

Your setup is tuned for the middle of the band which is a good place to be. Yep, anything below 2 is fine. Leave it as is and enjoy.
X2 on all that.
__________________
When you have a choice, buy American.

Jerry Bransford is online now   Quote Quick Reply
Old 05-01-2013, 11:16 AM   #11
Jeeper
 
Giantxtc's Avatar
 
Join Date: Apr 2012
Posts: 40
Thanks guys for getting me squared away. I've learned a lot.

Giantxtc is offline   Quote Quick Reply
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



logo carid shop wrangler parts carid fender flares custom wheels store avs deflectors at carid
» Rates
Get low rates on auto insurance in Canada!

» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 08:12 PM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC