[bryan1]

OK, I guess I'm just a complete idiot but I just don't understand how to ground my cb antenna.:scratchhe
My antenna only came with coaxial cable. anyone care to share their insight on this. my reception isn't bad. :whiteflag

 

[Ptack1]

i just plugged hte coaxial on there and into the CB and was done. I dont know about other grounding. I have it mounted on a metal bracket on the spare tire carrier.

 

[magnumpi]

It's not an electronic ground - it's a physical ground plane at the base of the antenna that reflects the energy radiating downward off the antenna & sends it up, where it will do you some good. It's not for reception - it's for transmission. You can buy a little thing that looks like an asterisk * that goes under the antenna & sticks out ~4" on each side. It works OK for antennae that can't be mounted on the vehicle so they have a real ground plane.

what he said

 

[El Bicho]

It's not an electronic ground - it's a physical ground plane at the base of the antenna that reflects the energy radiating downward off the antenna & sends it up, where it will do you some good. It's not for reception - it's for transmission. You can buy a little thing that looks like an asterisk * that goes under the antenna & sticks out ~4" on each side. It works OK for antennae that can't be mounted on the vehicle so they have a real ground plane.

Duh, don't they teach you anything in your Basic Radio Theory courses there in Oklahoma?!?!? I'm just messin' with ya, I didn't know either. :thumbup

 

[k1w1t1m]

If you use the standard metal mounting systems onto your truck it will be grounded. I have mine mounted to the tire rack. The coax is also grounded through the CB as well.

Do a search you will see how everybody mounts theirs.

 

[unixdude]

It's not an electronic ground - it's a physical ground plane at the base of the antenna that reflects the energy radiating downward off the antenna & sends it up, where it will do you some good. It's not for reception - it's for transmission. You can buy a little thing that looks like an asterisk * that goes under the antenna & sticks out ~4" on each side. It works OK for antennae that can't be mounted on the vehicle so they have a real ground plane.

Not exactly. Check out the following article: http://www.k2bj.com/Ground.htm. This article was written more for amateur radios, but the principles still apply. Here's another article: http://www.eham.net/articles/12944

 

[andrew351]

Is it a Wilson Antenna? Because if it is it should have that little star thing that Steve talking about already souldered to the coax. If not just follow what everyone else is saying.

 

[smileybry]

where do you have the antenna mounted? i have a fiberglass mounted on my spare tire carrier in the back. because it grounds out through the mount normally, i took a ground wire from the mount to a screw inside the tailgate seam on the quarter panel, since the spare tire carier is powder coated and doesnt provide a good ground. i can go out and get you a pic at lunchtime if you want it.

If you have you're antenna mounted somewhere else on the body (the bumper or the roof) you're good to go. also if its a whip with a magnet mount, you dont have to worry about it.

 

[bryan1]

Thanks for all the input. I have it mounted to my spare tire carrier. It's stands about a foot above the roof so i thought that would be far enough. The only reason I was asking this question was that I got caught up in some cb radio junkies thread somewhere else & felt ridiculously stupid!! From your input, apparently i mounted it properly. Thanks again.:thumbup

 

[andrew351]

Thanks for all the input. I have it mounted to my spare tire carrier. It's stands about a foot above the roof so i thought that would be far enough. The only reason I was asking this question was that I got caught up in some cb radio junkies thread somewhere else & felt ridiculously stupid!! From your input, apparently i mounted it properly. Thanks again.:thumbup

A foot wont get you much in the way of broadcast or transmission unless all you are using it for is chatting with your buddies back and forth on the trail. If you actually want to get some highway output, roof mount is the only way to go, but it is very impractical for most people to do.

 

[bryan1]

You guessed it-I only use it for chatting with my buddies on the trail. I have a scanner on board that i listen to, when i'm bored of course!

 

[andrew351]

Height above the camper shell is meaningless - the fiberglass doesn't affect radio waves, and the steel reinforcement at the back isnt' big enough to matter. The ground plane will be the bed floor, and the cab roof & B-pillars won't block much. So you'll get better transmission to the LF than any other direction.

I think that the fiberglass does affect it. Say that you have a roof rack and have it not loaded. Then you load up a bunch of non-metallic luggage, your SWR is going to change. And even having the door open or somebody standing nearby will affect the SWR as well. So with these points in mind, why would the top not affect it?

 

[andrew351]

Well, you're wrong. Take a few physics courses.

Well my area of study is Accounting and Finance, so I'll have to trust you with the physics. Though I am still a little skepticle. What about the people standing nearby affecting the SWR?

 

[smileybry]

Well my area of study is Accounting and Finance, so I'll have to trust you with the physics. Though I am still a little skepticle. What about the people standing nearby affecting the SWR?

people are conductors......

 

[andrew351]

Okay well I guess that I was saying SWR and I just assumed you guys would know what I mean by that. My bad, because you are right, they are not the same thing. I really meant signal strength then. So if somebody standing nearby affects signal strength, why would a fiberglass top not?

 

[smileybry]

Okay well I guess that I was saying SWR and I just assumed you guys would know what I mean by that. My bad, because you are right, they are not the same thing. I really meant signal strength then. So if somebody standing nearby affects signal strength, why would a fiberglass top not?

The top is relativly thin and doesnt conduct. Its like when you're in a building with your cell phone. You go to the window and you get better reception than when you're by a metal framed wall (most office buildings ahve metal studs)

different materials affect attenuation differently. fiberglass is a dielectric (non conductive) and they can either absorb or pass the signals through. the attenuation coefficient of fiberglass is fairly low (as is glass, paper, wood and drywall) allowing radio waves to pass through without being absorbed or reflected. Radio waves are not like light waves, and can go through what you cannot see.

People on the other hand have a high attenuation coefficient, are thick, and blood etc contain minerals which are conductive so they will absorb more signals.

If you want a demo of this "in action" go to your microwave. put in a paper plate and a chunk of meat both for 5 minutes. The plate will allow almost all the waves to pass through it, and absorb almost none. The meat will absorb almost any waves comming at it, and will turn that energy into heat (and become cooked).


Sorry for the long post. I'm a techie so i deal with this stuff all the time (and users who go "how come my wireless connection works at home but wont work here in the office...").

One more thing to consider is tint on the windows. BMW's etc have ceramic based tint to allow radio waves to pass through more effectively (for the navigation systems). Regular metalic based tints will reflect or conduct away most of the signal.

 

[andrew351]

Thanks guys, that stuff makes perfect sense. So you guys or both saying that the top does affect it, but the difference is negligible. That makes perfect sense. It's just that before you guys were making it sound like it didn't matter whether or not the top was there or not, it would be exactly the same. I'm sure you guys can see how this would not make sense to me. That attenuation coefficient makes perfect sense also. I guess that it is kind of like a coefficient of friction for radio waves. I suppose along those same principles would be that wood does not conduct heat, but metal does. Well I am glad I got this issue cleared up for my own piece of mind. This makes perfect sense now. Though I still think that the best way to mount an antenna is on the roof like I have it.

Andrew

 

[jam0o0]

i didn't know that about window tint thanks. i had my dual antenas on my rear bumper but the pasenger side one always rubbed on the spare tire carrier and now that i'm building a new bumper out of round tube i'm thinking that making a mount to bolt between my top and the bed rail in the back might get me better performance. any thoughts?

 

[smileybry]

yeah to simplify it..coeffecient of friction for radio waves...i'll take that... Now putting it on the roof gets you way better reception/transmission range because you're higher up. I have mine mounted on the tire carrier, good for a few miles highway, and chatting it up on the trail...

 

[smileybry]

i didn't know that about window tint thanks. i had my dual antenas on my rear bumper but the pasenger side one always rubbed on the spare tire carrier and now that i'm building a new bumper out of round tube i'm thinking that making a mount to bolt between my top and the bed rail in the back might get me better performance. any thoughts?

the one on my friends blazer is there. You can get one that is made for a stake hole or a flat one should work ok if you want to do that.

I used the one for International trucks on my tire holder. internationals have REALLY big tubing for their mirrors, so it fit perfectly on my spare tire mount..
http://www.cbshop.webtrix.net/scripts/prodList.asp?idCategory=126

http://www.cbshop.webtrix.net/scripts/prodView.asp?idproduct=917