SWR issue - Page 2 - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > General Technical Discussions > Electrical, Audio, GPS, & 2-Way Radio > SWR issue

ZONE 4.25" combo lift for TJ available at Rockridge4wJeep Wrangler Bushwacker Flat Fender Flare Sale at BaselinRIGID LED Light Blowout Sale - All Sizes, All Series, all

Reply
Unread 10-08-2013, 09:56 PM   #16
Agent620
Registered User
1999 TJ Wrangler 
 
Join Date: Aug 2010
Location: Classified, California
Posts: 1,055
Quote:
Originally Posted by JPNinPA View Post
I'd start over with basics.
Verify continuity of the center conductor from the back of the radio to the tip if the antenna.
Then continuity and resistance od the outer shield at the back of the radio to a good ground point on the body of the vehicle.
Verify there is no continuity between the center conductor to the outer shield at the radio. Do all without disassembling the antenna just remove the cable from the back of the radio.
Resistance in the ground should be under 5 ohms. The lower the better.
If you do not have these continuities where you should there is something broken, damaged or installed improperly.


You mention your antenna is on the rear tailgate? The hinges make poor ground conductors and cause many SWR issues.
Help me understand what any of that has to do with my issue when my 4ft antenna gets perfect SWR with making no changes to the radio or cable, just swapping antennas. The resistance would be the same as the ground is not changed. Plenty of people use the tailgate as an antenna mount and have no issue, even stu-offroad did it.

I am going to change the mounting bracket this weekend to raise up the antenna above the soft top to see if that helps at all. Until then I am assuming the antenna needs to be taller and that is my issue.

__________________
[B][COLOR="Blue"]Thanks to Anticanman who gave me a membership![/COLOR][/B]
[QUOTE=Anticanman;15443763]Chris Hansen is reading this thread.

If you've ever been in that traffic, you would have ground down the steering wheel with a death grip too. "Just ****ing GOOOOOO!!!!"[/QUOTE]
[QUOTE=Luuca;15713642]I pitty anyone who tries to reach into that netting unaware.[/QUOTE]
'99 TJ (DD)
'89 XJ (WIP)
Agent620 is offline   Reply With Quote Quick reply to this message
Unread 10-09-2013, 11:25 AM   #17
JPNinPA
Registered User
2005 LJ Wrangler 
 
Join Date: Feb 2011
Location: Dayton, Ohio
Posts: 2,258
If you tested the 4ft antenna inside the garage like you did with the 3ft then those SWR readings aren't trustworthy. Disassembling and reassembling could uncover issues like a internal broken stud isolation, Isolation washer. Sometimes weak cables only need some movement to uncover issues with broken center conductors or insulation. This will also test the antenna in the event you have a broken antenna. BTW what brand model antenna are you using?

You are correct. Many do run antenna off the tailgate and many of them add additional ground wires, due to the need of a good RF ground plane.

If you think it's too much trouble, don't do it. At a min check continuity of the shorter antenna.

PS besides the soft top frame is there any other large metal object within 3-4 inches of the load section of the antenna?
__________________
"Never look down on anyone unless your helping them up"- Jesse Jackson
JPNinPA is offline   Reply With Quote Quick reply to this message
Unread 10-09-2013, 10:33 PM   #18
Agent620
Registered User
1999 TJ Wrangler 
 
Join Date: Aug 2010
Location: Classified, California
Posts: 1,055
Quote:
Originally Posted by JPNinPA View Post
If you tested the 4ft antenna inside the garage like you did with the 3ft then those SWR readings aren't trustworthy. Disassembling and reassembling could uncover issues like a internal broken stud isolation, Isolation washer. Sometimes weak cables only need some movement to uncover issues with broken center conductors or insulation. This will also test the antenna in the event you have a broken antenna. BTW what brand model antenna are you using?

You are correct. Many do run antenna off the tailgate and many of them add additional ground wires, due to the need of a good RF ground plane.

If you think it's too much trouble, don't do it. At a min check continuity of the shorter antenna.

PS besides the sod top frame is there any other large metal object within 3-4 inches of the load section of the antenna?
The swr didnt change outside the garage when testing the 3ft. The 4ft was tested in the driveway the day before.

Cable is brand new, only a few months old. Brands are firefly and firestik.

Nothing near the antenna besides the soft top frame, tailgate, and mount. I will try to test eh OHM's this weekend but until then I have no free time to get the meter out and play with it. The antenna is literally brand new, right out of the package last week.
__________________
[B][COLOR="Blue"]Thanks to Anticanman who gave me a membership![/COLOR][/B]
[QUOTE=Anticanman;15443763]Chris Hansen is reading this thread.

If you've ever been in that traffic, you would have ground down the steering wheel with a death grip too. "Just ****ing GOOOOOO!!!!"[/QUOTE]
[QUOTE=Luuca;15713642]I pitty anyone who tries to reach into that netting unaware.[/QUOTE]
'99 TJ (DD)
'89 XJ (WIP)
Agent620 is offline   Reply With Quote Quick reply to this message
Unread 10-10-2013, 06:47 AM   #19
Leeworthy
Registered User
 
Join Date: Jun 2007
Location: Ontario
Posts: 67
Check swr on 3 channels. 1,19,40
Leeworthy is offline   Reply With Quote Quick reply to this message
Unread 10-10-2013, 07:46 PM   #20
Agent620
Registered User
1999 TJ Wrangler 
 
Join Date: Aug 2010
Location: Classified, California
Posts: 1,055
See above for those SWR readings.
__________________
[B][COLOR="Blue"]Thanks to Anticanman who gave me a membership![/COLOR][/B]
[QUOTE=Anticanman;15443763]Chris Hansen is reading this thread.

If you've ever been in that traffic, you would have ground down the steering wheel with a death grip too. "Just ****ing GOOOOOO!!!!"[/QUOTE]
[QUOTE=Luuca;15713642]I pitty anyone who tries to reach into that netting unaware.[/QUOTE]
'99 TJ (DD)
'89 XJ (WIP)
Agent620 is offline   Reply With Quote Quick reply to this message
Unread 10-11-2013, 05:05 AM   #21
Leeworthy
Registered User
 
Join Date: Jun 2007
Location: Ontario
Posts: 67
Any reason you want the 3ft instead of 4? The higher the antenna the easier to tune and the better signal you will send and receive. The best antenna is technically a 108" whip. That gives you the best of both.
Leeworthy is offline   Reply With Quote Quick reply to this message
Unread 10-11-2013, 08:39 AM   #22
Agent620
Registered User
1999 TJ Wrangler 
 
Join Date: Aug 2010
Location: Classified, California
Posts: 1,055
Quote:
Originally Posted by Leeworthy View Post
Any reason you want the 3ft instead of 4? The higher the antenna the easier to tune and the better signal you will send and receive. The best antenna is technically a 108" whip. That gives you the best of both.
Reason is in my first post. I cannot fit in my parking spot.
__________________
[B][COLOR="Blue"]Thanks to Anticanman who gave me a membership![/COLOR][/B]
[QUOTE=Anticanman;15443763]Chris Hansen is reading this thread.

If you've ever been in that traffic, you would have ground down the steering wheel with a death grip too. "Just ****ing GOOOOOO!!!!"[/QUOTE]
[QUOTE=Luuca;15713642]I pitty anyone who tries to reach into that netting unaware.[/QUOTE]
'99 TJ (DD)
'89 XJ (WIP)
Agent620 is offline   Reply With Quote Quick reply to this message
Unread 10-13-2013, 08:24 PM   #23
CJ7-Tim
Real Jeeps have dents.
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis, Minnesota
Posts: 21,716
Quote:
Originally Posted by Agent620 View Post
....my 4ft antenna gets perfect SWR with making no changes to the radio or cable, just swapping antennas.
Although very rare, I might suspect a faulty 3 foot antenna.

What brand/model of antenna ?
__________________
.

Between 2009 when Obama took office, and 2013, median annual household incomes have fallen by more than $2,100.

Progressive Liberalism: Bringing you new Healthcare ideas so wonderful, they have to include mandatory participation ......

Originally Posted by Ronald W. Reagan: Government is not the solution to our problems; Government is the problem.
CJ7-Tim is offline   Reply With Quote Quick reply to this message
Unread 10-14-2013, 05:04 AM   #24
Leeworthy
Registered User
 
Join Date: Jun 2007
Location: Ontario
Posts: 67
I think it's a fire stick. It could be a broken coil
Leeworthy is offline   Reply With Quote Quick reply to this message
Unread 10-14-2013, 09:00 PM   #25
TheHeretic
Kool Kat 4x4
 
TheHeretic's Avatar
2005 TJ Wrangler 
 
Join Date: Sep 2009
Location: Innisfil, Ontario
Posts: 677
The problem with an SWR of 2, is you're only effectively radiating 2 watts of power. First, as others have suggested: Make sure you have continuity between the coax shield (outer barrel of a PL-259, or similar), and a part of the jeep that is connected to the frame. For clarity, cable length is not a myth, HOWEVER, when we get concerned with cable lengths is when you get to the 50 foot mark, or thereabouts. You're dealing with a cable that's about 18' which is what a standard pre-fab cable tends to be for CB. Not enough to be concerned with. One thing you can do, is create an RF choke. Basically you make 5 to 6 loops about 5" in diameter. Make the choke where the antenna attaches to the coax. A choke is important, and many fail to do this. Another thing is check your coax. How old is it? has water made its way into connector? This can cause an issue as well. If you're going to replace the coax, I would recommend RG-8X, as it's easy to work with, has low loss for the length you're using, and is not overtly expensive. Get good quality cable though, order it from an Amateur Radio store. If you are having a cable custom made, ask for silver plated connectors, as silver is the best conductor. As previously stated, a 1/4 wave whip will be much easier to tune, ceteris paribus. I remove my antenna before I put my jeep in the garage.
__________________
VA3IPB

The only True Professional Mechanic in the Greater Toronto Area for Modified Jeeps, and trucks. If Rock Spyder hasn't seen it before, or done it before, you don't need it.

http://rockspyder4x4.com

http://koolkat4x4.org
TheHeretic is offline   Reply With Quote Quick reply to this message
Unread 10-14-2013, 09:14 PM   #26
TheHeretic
Kool Kat 4x4
 
TheHeretic's Avatar
2005 TJ Wrangler 
 
Join Date: Sep 2009
Location: Innisfil, Ontario
Posts: 677
Quote:
Originally Posted by JPNinPA View Post
This ^^ Be sure your cable is not looped into a RF choke.

Or pinched by making sharp turns.
Actually, you want an RF choke. You want the antenna to be the radiator, not the feedline.
__________________
VA3IPB

The only True Professional Mechanic in the Greater Toronto Area for Modified Jeeps, and trucks. If Rock Spyder hasn't seen it before, or done it before, you don't need it.

http://rockspyder4x4.com

http://koolkat4x4.org
TheHeretic is offline   Reply With Quote Quick reply to this message
Unread 10-15-2013, 11:18 AM   #27
CJ7-Tim
Real Jeeps have dents.
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis, Minnesota
Posts: 21,716
An SWR of 2.0:1 is an 11% loss of power radiated, not 50%.

http://www.firestik.com/Tech_Docs/SWRLOSS.htm
__________________
.

Between 2009 when Obama took office, and 2013, median annual household incomes have fallen by more than $2,100.

Progressive Liberalism: Bringing you new Healthcare ideas so wonderful, they have to include mandatory participation ......

Originally Posted by Ronald W. Reagan: Government is not the solution to our problems; Government is the problem.
CJ7-Tim is offline   Reply With Quote Quick reply to this message
Unread 10-16-2013, 11:23 AM   #28
TheHeretic
Kool Kat 4x4
 
TheHeretic's Avatar
2005 TJ Wrangler 
 
Join Date: Sep 2009
Location: Innisfil, Ontario
Posts: 677
Quote:
Originally Posted by CJ7-Tim View Post
An SWR of 2.0:1 is an 11% loss of power radiated, not 50%.

http://www.firestik.com/Tech_Docs/SWRLOSS.htm
....And where is the rest of those watts going?? Back into your radio. Sure, it's only a total of 4 watts, but considering the less then steller quality of components used in CB radios, I'd rather not take the chance.
__________________
VA3IPB

The only True Professional Mechanic in the Greater Toronto Area for Modified Jeeps, and trucks. If Rock Spyder hasn't seen it before, or done it before, you don't need it.

http://rockspyder4x4.com

http://koolkat4x4.org
TheHeretic is offline   Reply With Quote Quick reply to this message
Unread 10-16-2013, 05:36 PM   #29
CJ7-Tim
Real Jeeps have dents.
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis, Minnesota
Posts: 21,716
Nearly all modern CB's have protection circuits for the finals. An SWR of 2.0 is not ideal, but there are no worries about damage to the radio at 2.0:1.

1.5:1 or less is the target to shoot for. To me, an SWR of 2.0 indicates one or more of the following: poor quality antenna components, faulty antenna components, incorrect installation, poor choice of antenna mounting location.
__________________
.

Between 2009 when Obama took office, and 2013, median annual household incomes have fallen by more than $2,100.

Progressive Liberalism: Bringing you new Healthcare ideas so wonderful, they have to include mandatory participation ......

Originally Posted by Ronald W. Reagan: Government is not the solution to our problems; Government is the problem.
CJ7-Tim is offline   Reply With Quote Quick reply to this message
Unread 10-16-2013, 07:56 PM   #30
TheHeretic
Kool Kat 4x4
 
TheHeretic's Avatar
2005 TJ Wrangler 
 
Join Date: Sep 2009
Location: Innisfil, Ontario
Posts: 677
Quote:
Originally Posted by CJ7-Tim View Post
Nearly all modern CB's have protection circuits for the finals. An SWR of 2.0 is not ideal, but there are no worries about damage to the radio at 2.0:1.

1.5:1 or less is the target to shoot for. To me, an SWR of 2.0 indicates one or more of the following: poor quality antenna components, faulty antenna components, incorrect installation, poor choice of mounting location.
Both my CB and 2m HAM radio operate between 1.2 ~ 1.3. Good quality radios will have some protection, but few CB manufacturers are doing that. I'd be surprised if any of them, other then the ubber high end stuff. I'm not a CB'r so I don't really know what those manufacturers consider to be okay. I know my Yaesu FTM-350 has protection for up to an SWR of 3, but when I bought that radio new it was also $650. A $60 CB I don't think is going to have that kind of protection. I could be wrong, like I said not a CB'r.
__________________
VA3IPB

The only True Professional Mechanic in the Greater Toronto Area for Modified Jeeps, and trucks. If Rock Spyder hasn't seen it before, or done it before, you don't need it.

http://rockspyder4x4.com

http://koolkat4x4.org
TheHeretic is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
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






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.