Any knowledgeable hams? - Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > General Jeep Discussions > 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 03-28-2013, 01:52 PM   #1
Jeeper
 
OhSixTJ's Avatar
 
Join Date: Mar 2013
Posts: 1,110
OhSixTJ is on a distinguished road
Any knowledgeable hams?

Better antenna for an Arizona spare tire mounted 2m antenna: 5/8 or 1/2 no ground plane?

My jeep is a soft top, btw.
OhSixTJ is offline   Quote
Old 03-28-2013, 03:01 PM   #2
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 41,855
Jerry Bransford is on a distinguished road
Never use a NGP antenna when the vehicle has a steel tub & frame like the Wrangler does which serves as superb ground plane. NGP antennas are poor performers at best and are only meant for use in installations where no suitable ground plane is available, like on a fiberglass boat.

Just make sure your antenna's mount has a good bare-metal connection to the Jeep so it gets a good RF ground connection so it can turn the Jeep into a good ground plane.

N6TAY

__________________
When you have a choice, buy American.
Jerry Bransford is online now   Quote
Old 03-28-2013, 03:27 PM   #3
Jeeper
 
OhSixTJ's Avatar
 
Join Date: Mar 2013
Posts: 1,110
OhSixTJ is on a distinguished road
Quote:
Originally Posted by Jerry Bransford View Post
Never use a NGP antenna when the vehicle has a steel tub & frame like the Wrangler does which serves as superb ground plane. NGP antennas are poor performers at best and are only meant for use in installations where no suitable ground plane is available, like on a fiberglass boat.

Just make sure your antenna's mount has a good bare-metal connection to the Jeep so it gets a good RF ground connection so it can turn the Jeep into a good ground plane.

N6TAY
Got it. I did get a signal report that I was full-quieting into the repeater but it was only 10 miles away and I was pushing 65 watts haha I'll stick with the 5/8.
OhSixTJ is offline   Quote
Old 03-28-2013, 08:48 PM   #4
Desert Dweller

5-Year WF Supporting Member
 
Wrong Way Hal's Avatar
 
Join Date: Jan 2012
Location: Ridgecrest, CA
Posts: 632
Wrong Way Hal is on a distinguished road
There is NOTHING wrong with 1/2 wave antennas. Thousands of owners of dipoles (1/4 wave each side = 1/2 wave), thousands of owners of 1/2 wave mobile antennas will all tell you they WORK !!!!!! There is NOTHING wrong with 1/2 wave antennas. In fact, they work BETTER than 1/4 wave and 5/8 wave antennas when no ground plane is available.

In the case of an installation where the antenna is at the rear or front or anywhere except center of the vehicle, a 1/2 wave antenna will provide BETTER performance in a 360 degree circle. When you mount a 1/4 wave or 5/8 wave antenna on the corner or spare tire mount, the only ground plane that the antenna is going to see, and use, is in the direction of the front of the vehicle. These types of antennas NEED a ground plane in all directions. In the direction where there is no ground plane, your signal is going up, down, and every direction EQUALLY. This might be fine if you want to talk to people 5 miles below you, or an airplane overhead. When the antenna has a ground plane under it in the direction you want your signal to go, almost ALL of your signal is going towards the horizon.

If all of your communications is going to be with stations in front of you (with spare tire mount) or in the direction of left rear to right front or right rear to left front, then by all means, mount a 1/4 wave or 5/8 wave on one of the rear corners. Or, you can mount your antenna as just mentioned and use 65 watts and jam a lot of other users. If you use a 1/2 wave antenna, mounted anywhere on your vehicle, you should have equal radiation and reception in all directions.

In theory, there should only be a maximum of 2dB difference between a 1/2 wave and 5/8 wave mobile antenna. A properly calibrated S meter requires a difference of 6 dB for every 1 S unit. In theory, you will not be able to hear or see the difference.

Speaking of 65 watts, I'm sure you remember some of the material you studied for your test. FCC Part 97.313 Transmitter power standards:

(a) An amateur station must use the minimum transmitter power necessary to carry out the desired communications.

Regards,
__________________
Wrong Way Hal
1972 C-101 / 1984 CJ-7 / 2012 JKR
Wrong Way Hal is offline   Quote
Old 03-28-2013, 09:38 PM   #5
Jeeper
 
OhSixTJ's Avatar
 
Join Date: Mar 2013
Posts: 1,110
OhSixTJ is on a distinguished road
Quote:
Originally Posted by n6hal View Post
There is NOTHING wrong with 1/2 wave antennas. Thousands of owners of dipoles (1/4 wave each side = 1/2 wave), thousands of owners of 1/2 wave mobile antennas will all tell you they WORK !!!!!! There is NOTHING wrong with 1/2 wave antennas. In fact, they work BETTER than 1/4 wave and 5/8 wave antennas when no ground plane is available.

In the case of an installation where the antenna is at the rear or front or anywhere except center of the vehicle, a 1/2 wave antenna will provide BETTER performance in a 360 degree circle. When you mount a 1/4 wave or 5/8 wave antenna on the corner or spare tire mount, the only ground plane that the antenna is going to see, and use, is in the direction of the front of the vehicle. These types of antennas NEED a ground plane in all directions. In the direction where there is no ground plane, your signal is going up, down, and every direction EQUALLY. This might be fine if you want to talk to people 5 miles below you, or an airplane overhead. When the antenna has a ground plane under it in the direction you want your signal to go, almost ALL of your signal is going towards the horizon.

If all of your communications is going to be with stations in front of you (with spare tire mount) or in the direction of left rear to right front or right rear to left front, then by all means, mount a 1/4 wave or 5/8 wave on one of the rear corners. Or, you can mount your antenna as just mentioned and use 65 watts and jam a lot of other users. If you use a 1/2 wave antenna, mounted anywhere on your vehicle, you should have equal radiation and reception in all directions.

In theory, there should only be a maximum of 2dB difference between a 1/2 wave and 5/8 wave mobile antenna. A properly calibrated S meter requires a difference of 6 dB for every 1 S unit. In theory, you will not be able to hear or see the difference.

Speaking of 65 watts, I'm sure you remember some of the material you studied for your test. FCC Part 97.313 Transmitter power standards:

(a) An amateur station must use the minimum transmitter power necessary to carry out the desired communications.

Regards,
The "haha" was meant as a "whoops!" kinda thing, I do remember that part but didn't check what output I was using when I called out. And with my tm-281 it's either 25 or 65, I just so happened to be on 65. But thanks for the reminder.

Back to the topic:
So the jeep won't "pull" the signal to the front if a 1/2 NGP antenna is used? It'll radiate a full 360 degrees? (This part I paid no attention to apparently)
OhSixTJ is offline   Quote
Old 03-28-2013, 09:50 PM   #6
Desert Dweller

5-Year WF Supporting Member
 
Wrong Way Hal's Avatar
 
Join Date: Jan 2012
Location: Ridgecrest, CA
Posts: 632
Wrong Way Hal is on a distinguished road
That is correct. In theory, a 1/2 wave antenna will radiate, and receive, equally in all directions, irregardless of what the antenna is mounted on or whether a ground plane exists. In reality, there might be a tiny bit of increased signal strength in the direction of the ground plane, but should be undetectable without test equipment.

73
__________________
Wrong Way Hal
1972 C-101 / 1984 CJ-7 / 2012 JKR
Wrong Way Hal is offline   Quote
Old 03-28-2013, 09:53 PM   #7
Jeeper
 
OhSixTJ's Avatar
 
Join Date: Mar 2013
Posts: 1,110
OhSixTJ is on a distinguished road
Quote:
Originally Posted by n6hal View Post
That is correct. In theory, a 1/2 wave antenna will radiate, and receive, equally in all directions, irregardless of what the antenna is mounted on or whether a ground plane exists. In reality, there might be a tiny bit of increased signal strength in the direction of the ground plane, but should be undetectable without test equipment.

73
Ok. Thanks for the info. I'll try the 1/2 out. Larsen!
OhSixTJ is offline   Quote
Old 03-29-2013, 11:41 AM   #8
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 41,855
Jerry Bransford is on a distinguished road
Quote:
Originally Posted by n6hal View Post
There is NOTHING wrong with 1/2 wave antennas. Thousands of owners of dipoles (1/4 wave each side = 1/2 wave), thousands of owners of 1/2 wave mobile antennas will all tell you they WORK !!!!!! There is NOTHING wrong with 1/2 wave antennas. In fact, they work BETTER than 1/4 wave and 5/8 wave antennas[b/ when no ground plane is available.[/b]
The OP's question wasn't what wavelength antenna works best, it was whether a conventional 5/8 would work better than a 1/2 wave NGP. This isn't about 5/8 vs. 1/2 wave, it was which would make a better antenna... a NGP 1/2 wave or a 5/8. NGP vs a conventional antenna that makes use of his TJ's available ground plane characteristics.

He didn't request a lesson on what wavelength antennas work best... it was really just a NGP vs. a conventional type of antenna question and there is no doubt a NGP type of antenna is not going to work nearly as well on a TJ as a conventional antenna that takes advantage of a groundplane will.

If you take the NGP part out, then it's time to talk about which wavelength antenna will perform best... but he asked about using a NGP antenna which is little better than nothing at all.
__________________
When you have a choice, buy American.
Jerry Bransford is online now   Quote
Old 03-29-2013, 11:43 AM   #9
Jeeper
 
OhSixTJ's Avatar
 
Join Date: Mar 2013
Posts: 1,110
OhSixTJ is on a distinguished road
Quote:
Originally Posted by Jerry Bransford View Post
The OP's question wasn't what wavelength antenna works best, it was whether his 5/8 would work better than his 1/2 wave NGP. This isn't about 5/8 vs. 1/2 wave, it was which would make a better antenna... a NGP 1/2 wave or a 5/8. NGP vs a conventional antenna that makes use of his TJ's available ground plane characteristics.

He didn't request a lesson on what wavelength antennas work best... it was really just a NGP vs. a conventional type of antenna question and there is no doubt a NGP is not going to work as well on a TJ as a conventional antenna that takes advantage of a groundplane will.
So many confusing replies! Haha I'm just gonna leave the 5/8 on until someone tells me they can't hear me well.
OhSixTJ is offline   Quote
Old 03-29-2013, 11:51 AM   #10
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 41,855
Jerry Bransford is on a distinguished road
There is no confusion on the basic fact I have been trying to get across... that a NGP antenna isn't going to work nearly as well as an antenna that makes use of the Jeep as a ground plane. I didn't need to get into an encyclopedic dissertation on antenna theory for the simple answer you appeared to be seeking so I didn't.

__________________
When you have a choice, buy American.
Jerry Bransford is online now   Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not 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




Download our Mobile App

» Featured Product

All times are GMT -5. The time now is 01:59 AM.


User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.

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