Ground plane vs no ground plane antennas for Jeep Wranglers.

[Charlie W2YBX]

Hello!

I'm looking to outfit my Wrangler JK with the following transceivers:

Ham: Icom DI-5100a Dual band DSTAR
CB: Uniden Pro520 XL

I've read a bunch of articles and forum threads regarding where and where not to mount antennas on a Wrangler, none that I've come across talk about using ground plane vs no ground plane antennas.

The best place for an antenna is the top center of a vehicles metal roof (which I don't have). I can use a ground plane antenna and it will under perform (at different levels) regardless of where I mount it, or I can use a no ground plane antenna and from what I have read, expect a 15% loss in performance (or more) from a properly performing gp antenna, again regardless of where I mount it. I'm not sure which way to go.

Thanks for any help!

 

[Prerunner1982]

For the ID-5100a you can run a 1/2 wave 2m antenna as it is not ground dependent and still get good performance. 70cm requires such little ground plane you can mount the antenna to anything metal and likely be sufficient.

For the CB antenna I typically recommend the front fender or a taillight mount which is not available for the JK but you could put a ball mount or half of a mirror mount directly to the body (if you are willing) or there is a mount that connects to the body inside of the license plate holder. I generally try to steer people away from the tailgate/sparetire mounting location though it is the most popular. Sure you could run a braided ground strap from the mount to the body and get a decent SWR but it's really not the most efficient setup for a CB antenna. I have seen VHF/UHF antennas work ok on the back with an elevated Arizona Rocky Road mount.

RF bonding can also help. Run braided ground straps from the hood to the body, body to frame (more than one), exhaust to frame (more than one), etc.

www.K0BG.com is a good website for mobile radio operation.

 

[Charlie W2YBX]

For the ID-5100a you can run a 1/2 wave 2m antenna as it is not ground dependent and still get good performance. 70cm requires such little ground plane you can mount the antenna to anything metal and likely be sufficient.

For the CB antenna I typically recommend the front fender or a taillight mount which is not available for the JK but you could put a ball mount or half of a mirror mount directly to the body (if you are willing) or there is a mount that connects to the body inside of the license plate holder. I generally try to steer people away from the tailgate/sparetire mounting location though it is the most popular. Sure you could run a braided ground strap from the mount to the body and get a decent SWR but it's really not the most efficient setup for a CB antenna. I have seen VHF/UHF antennas work ok on the back with an elevated Arizona Rocky Road mount.

RF bonding can also help. Run braided ground straps from the hood to the body, body to frame (more than one), exhaust to frame (more than one), etc.

www.K0BG.com is a good website for mobile radio operation.

Thanks for the response, that's great info!

Forgive me for asking , I'm relatively new to ham, I was going to use one antenna for both 2m and 70cm. Do you recommend using 2 seperate antennas and switching between them?

 

[Prerunner1982]

Thanks for the response, that's great info!
Forgive me for asking , I'm relatively new to ham, I was going to use one antenna for both 2m and 70cm. Do you recommend using 2 seperate antennas and switching between them?

No, a dual band antenna will be fine and easier.
The Larsen 2/70 is typically regarded as being the best antenna for offroad however I have run the Browning BR-180-b antenna for years, they get smacked against trees daily and have held up great.

 

[Charlie W2YBX]

No, a dual band antenna will be fine and easier.
The Larsen 2/70 is typically regarded as being the best antenna for offroad however I have run the Browning BR-180-b antenna for years, they get smacked against trees daily and have held up great.

I’ll check out the browning antenna! Also I think I’m going to mount everything on springs to lessen the chances of breakage. I was also looking into antennas that fold so I can lower them when I have to.


Sent from my iPhone using OB Talk

 

[Captain Chaos]

I run a Larsen 2/70 on my trail rack with a firestick cb antenna on the other side. The antennas are over 3’ apart, so they do not interfere with each other, and my SWR readings are below 2.
I also have a icom 5100, it’s an awesome radio!

 

[firelight]

I used a Cooltech Ultramount antenna mount on my JKU for CB, and had great results with it, using a 4' firestick or a removable mount. This is what I believe Prerunner1982 was referring to when mentioning the license plate mount. I'll try to post a link for it below. I had very good SWR reading using it. As a matter of fact, before I got my own SWR meter, I stopped by a CB shop at a truck stop to have the antenna tested before installing my CB. It was amusing having the guy bad mouth online bought CB gear as he walked with me to my Jeep (not very professional) only to have it test perfectly. He didn't say anything as he walked away; didn't even charge me for it.

http://www.cooltechllc.com/wrangler-parts-accessories/47-ultramount-cb-antenna-system.html

 

[Charlie W2YBX]

I used a Cooltech Ultramount antenna mount on my JKU for CB, and had great results with it, using a 4' firestick or a removable mount. This is what I believe Prerunner1982 was referring to when mentioning the license plate mount. I'll try to post a link for it below. I had very good SWR reading using it. As a matter of fact, before I got my own SWR meter, I stopped by a CB shop at a truck stop to have the antenna tested before installing my CB. It was amusing having the guy bad mouth online bought CB gear as he walked with me to my Jeep (not very professional) only to have it test perfectly. He didn't say anything as he walked away; didn't even charge me for it.

http://www.cooltechllc.com/wrangler-parts-accessories/47-ultramount-cb-antenna-system.html

Is there a huge difference regarding performance between mounting the antenna on the license plate vs the rear tire carrier?

 

[firelight]

Is there a huge difference regarding performance between mounting the antenna on the license plate vs the rear tire carrier?

First off, I'm no expert. I wanted a 4' (adjustable, Firefly) antenna, so I was concerned about mounting it on the spare tire carrier strictly due to its vulnerability up there. I also liked the idea that the wiring would be stationary and not be moving every time I opened the back of the Jeep. That may be a moot point, but I decided that was another reason to locate it on the license plate frame. Ultimately, I got a rear tire carrier bumper (from Shrockworks) and had them drill a hole on the left side for me to mount the antenna there as I lost my stock license plate mounting location when I installed the bumper.

After I installed the Cooltech mount and installed the cb, I went for a ride on the interstate listening to truckers talk to see how far away I could hear and talk clearly. I waited until I hear a trucker mention his location to see how far away he was and then spoke to him. He never knew I was testing my radio for distance, only to make sure he could hear me. He could, and he was almost 6 miles away. the terrain here isn't flat, but not mountainous either.

 

[Anak]

I can't offer any help on the CB front, but for the ham bands you might also consider a Diamond NR770hb (or other variant of the NR770--it can be had in different finishes and different mounts). It offers 3.0 dBi of gain on 2M and 5.5 dBi of gain on 70cm. It is a radialless design (no ground plane needed) and has the ability to be folded over for clearance. At about $55 it is a good value in my book.

HRO link: https://www.hamradio.com/detail.cfm?pid=H0-000063

DX Engineering link: https://www.dxengineering.com/parts/dmn-nr770hb