I'm looking at mounting my CB antenna on the tire carrier. Any comments or opinions on whether to route it through the interior or along the frame?
C B Question
- Thread starter jaysdead40
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
flintknapper
I agree....also, unless it is a "no ground plane" antenna you might consider running a ground wire to the frame. Often times a tire carrier does not always provide a reliable ground for the antenna. Try to keep at least 2/3 rd's of the antenna above the roof line so that it can act as the ground plane.
MoJ said:
I agree....also, unless it is a "no ground plane" antenna you might consider running a ground wire to the frame. Often times a tire carrier does not always provide a reliable ground for the antenna. Try to keep at least 2/3 rd's of the antenna above the roof line so that it can act as the ground plane.
Flint is on to something here. Most folks think that if you have a good SWR, that you're golden. Truth is, there are other, measureable factors that effect the radiation pattern, and overall efficiency of any transmitting antenna.
One of the easiest inhancements is to make sure you have a good RF ground. RF ground is not DC ground, because RF voltage has considerably different characteristics than DC voltage. Simply because there is continuity (as measured by a meter) between the mount and ground, doesn't mean you have a good RF ground.
The further away from the body your mount is (as in on the bumper), the poorer an RF ground you will have. The solution is to run a wide (1/2" is usually ok) ground strap between the base of the antenna and the mount it is attached to. Then (if you are mounted to the bumper), run another ground strap between the bumper to the frame, and yet another from the frame to the body of the truck. This way you have a high current path to the body, even if you are not actually mounting your antenna to it.
In the image, you can see the strap between the base of the antenna and the hatch. There is another (hidden) strap between the hatch and the body itself.
You might be surprised how much more efficient an antenna can be when grounded this way.
BTW, properly soldered terminals are essential here; crimping alone is insufficient.
Cheers, R -
One of the easiest inhancements is to make sure you have a good RF ground. RF ground is not DC ground, because RF voltage has considerably different characteristics than DC voltage. Simply because there is continuity (as measured by a meter) between the mount and ground, doesn't mean you have a good RF ground.
The further away from the body your mount is (as in on the bumper), the poorer an RF ground you will have. The solution is to run a wide (1/2" is usually ok) ground strap between the base of the antenna and the mount it is attached to. Then (if you are mounted to the bumper), run another ground strap between the bumper to the frame, and yet another from the frame to the body of the truck. This way you have a high current path to the body, even if you are not actually mounting your antenna to it.
In the image, you can see the strap between the base of the antenna and the hatch. There is another (hidden) strap between the hatch and the body itself.
You might be surprised how much more efficient an antenna can be when grounded this way.
BTW, properly soldered terminals are essential here; crimping alone is insufficient.
Cheers, R -
Ron - please do tell about your antenna mount.
So did you have to drill any holes for that rear door mount?
Where does the braided ground strap tie to?
With the coax running past the weather stripping (if that's whats happening), does it close ok? Or is there a hole there?
Is this is permenant mount? or does it come off easy?
It does look good and well grounded with a low inductive ground.
Kind of weird talking antennas here as at work our RF team at work has been working hard to develop a tiny 850/900 Mhz & 1800/1900 Mhz banded antenna for the cellular bands. Talk about difficult matching and grounding.... it took them 9 months and it's still not totally done yet.
So did you have to drill any holes for that rear door mount?
Where does the braided ground strap tie to?
With the coax running past the weather stripping (if that's whats happening), does it close ok? Or is there a hole there?
Is this is permenant mount? or does it come off easy?
It does look good and well grounded with a low inductive ground.
Kind of weird talking antennas here as at work our RF team at work has been working hard to develop a tiny 850/900 Mhz & 1800/1900 Mhz banded antenna for the cellular bands. Talk about difficult matching and grounding.... it took them 9 months and it's still not totally done yet.
R -
>> So did you have to drill any holes for that rear door mount?
No holes; Allen head screws on the back to clamp it down.
>> Where does the braided ground strap tie to?
Terminates to a ring lug under the damper mounting plate.
>> With the coax running past the weather stripping (if that's whats happening), does it close ok? Or is there a hole there?
No hole; this piece is roughly equivalent to RG-174, so it's pretty small and flexible (to a degree...). Opens/closes fine, tho it helps to be gentle about it.
>> Is this is permenant mount? or does it come off easy?
Can be removed in 30 secs; no evidence it was even there.
>> It does look good and well grounded with a low inductive ground.
Very low, especially when the hatch is also grounded to the body. The bandwidth is therefore broader with a much better Q factor, and of course a flatter SWR across the band than it might otherwise be.
This particular mount is made by Diamond (they have several different mounts/variations for different mounting situations and anticipated antenna loads).
Cheers, R -
>> So did you have to drill any holes for that rear door mount?
No holes; Allen head screws on the back to clamp it down.
>> Where does the braided ground strap tie to?
Terminates to a ring lug under the damper mounting plate.
>> With the coax running past the weather stripping (if that's whats happening), does it close ok? Or is there a hole there?
No hole; this piece is roughly equivalent to RG-174, so it's pretty small and flexible (to a degree...). Opens/closes fine, tho it helps to be gentle about it.
>> Is this is permenant mount? or does it come off easy?
Can be removed in 30 secs; no evidence it was even there.
>> It does look good and well grounded with a low inductive ground.
Very low, especially when the hatch is also grounded to the body. The bandwidth is therefore broader with a much better Q factor, and of course a flatter SWR across the band than it might otherwise be.
This particular mount is made by Diamond (they have several different mounts/variations for different mounting situations and anticipated antenna loads).
Cheers, R -
- Thread starter
- #7
Thanks for the replies, especially Ron.
I'll have to PM you for some more detailed instruction when I get further into the install.
Also whats a source for the flat grounding strap you referred to.
I'll have to PM you for some more detailed instruction when I get further into the install.
Also whats a source for the flat grounding strap you referred to.
I ran my wire out through the DS rear quarter panel along side th drain hose from the sun roof. Here is a pic of my mount, simple but effective.
Last edited:
