CB Antenna ?

[hattrik21]

OK I mounted my cb to my factory rook rack which is aluminum. Now do I need to run a ground wire from the antenna mount to the body or is this optional?

[pskhaat]

Get yourself an SWR meter, they run pretty reasonably priced, and measure the value both at the antenna and at the radio. If you're under about 1.5 or so, you may be okay and have decent performance, but it's no guarantee. If you're way above ~1.5 at either end, it may eventually damage your radio.

I might leave the `ground' strap as a last resort and possibly do a hood- or roof-mount if possible?

[DaveInDenver]

The mount would need to be grounded if it's not getting it through the roof rack. Doesn't matter if the rack is steel or aluminum as long as the rack itself is not isolated from the body of the truck. Is this what you mean? I have an antenna on my ARB bumper and the powdercoat effectively isolated the mount electrically, so I ran a ground strap for that and if your rack is painted or clear coated, that might be the case for you as well.

[gary in ohio]

For a CB, the rack is find to mount to. Check the SWR but you shouldnt have an issue.

[adventureduo]

I have my CB antenna up on my rack and it had really bad SWR. But still worked fine for trail to trail talk. I could get out a few miles in the city. I felt that was good enough for a CB. I ended up grounding the entire rack. This helped when i went to install lights on it also. I didn't have to run additional ground cable up.

[hattrik21]

Thanks everyone. I'll get it tuned and go from there.

[tdesanto]

Thanks everyone. I'll get it tuned and go from there.

Daniel,

I have a meter. You probably need to ground the antenna. Aluminum is not the best electrical conductor. Great for heat, bad for electricity.

[frgtwn]

Aluminum is an excellent conductor. Better than copper. Most high voltage is aluminum. There are a lot of aluminum antennas. Don't stand under an aluminum street light in a thunderstorm.

For fun: http://www.answerbag.com/q_view/18570


Dale

[hattrik21]

Daniel,

I have a meter. You probably need to ground the antenna. Aluminum is not the best electrical conductor. Great for heat, bad for electricity.

Yes I will need tune my antenna so maybe we can do lunch next weekend or something? This weekend I'm changing out my diff fluids and resealing the rear cover so I won't be able to drive it for 24 hrs so if next weekend works, let me know and we can figure out a time/place.

[tdesanto]

Yes I will need tune my antenna so maybe we can do lunch next weekend or something? This weekend I'm changing out my diff fluids and resealing the rear cover so I won't be able to drive it for 24 hrs so if next weekend works, let me know and we can figure out a time/place.

Next weekend's out. I leave town next Thursday afternoon 8/10 for the whole weekend. Maybe we could meet after work one night next week? With two people, it's pretty quick to tune; however, tuning is only going to correct for minor SWR issues. If it turns out you have a ground issue, that's going to take some time.

If you suspect a grounding issue and have a DVM, check the continuity from the antenna mount to somewhere on the body/chasis (be sure to disconnect the antenna from the radio; otherwise, this test won't work). Also, make sure that your radio is grounded too.

Let me know what evening would work best for you. Or call me on my cell or email me tomorrow, I might be able to meet you this Sunday.

[gary in ohio]

The mount not only physically hold the antenna on the vehicle but also acts as part of the antenna, the counterpoise, the second side of the antenna, the groundplane. IF the rack is large enough it will work regardless if its grounded or not. Grounding just increases the size of the counterpoise. Also depending on the antenna you get, some dont require a counterpoise/groundplane. SO give ita try, if the SWR and signals are good then your done.

[hattrik21]

Here is a pic of the mount, just for reference for those that have been helping so far.

http://img406.imageshack.us/img406/6161/dscn4337nz4.jpg

[BogusBlake]

You probably ought to ground that.

[gary in ohio]

Three suggestions. Flip the mount over. Most of your stress will be down from a bending antenna. Second is usera right angle cable or adapter to get that sharp coax bend out of the picture. finally put some water proofing on the connector. coax seal is your best option. Otherwise nice little mount.

[hattrik21]

I'll flip the mount over and test it for a possible ground wire so it looks like I have one more project this weekend. OK everyone, thanks so far for the input.

[gary in ohio]

Run a wire from the antenna mount to a near by bolt then run a wire on the inside of the vehicle near the mount to a ground point. The metal rack is bolted to a metal roof. There is a ground there, you just need to help it along and get around some rust and paint.

[DaveInDenver]

That is the ARB antenna bracket, right? My bumper mounted antenna (I only have one now, used to have two) follow pretty much what Gary says. I ran a ground strap from the frame of my truck to the bumper and then each of the mounts got a short ground strap to the bumper. I would also suggest you knock off some of the powdercoat around the hole for the antenna and the hole the grounded bolt goes through. This helped a lot for me, it seems the powdercoat is a pretty decent insulator and equally tough for the mount to bite in to. It finally took a Dremel and a mini wire wheel to get the powdercoat to come off, sandpaper didn't do it on mine. I put dielectric grease under the mount when I installed it to keep the bare steel from rusting.

[hattrik21]

Yeah Dave it is the ARB mount used in another way :). Gary thanks for the ideas. I'm off to get working on it now.

[Jacket]

I'm in the process of switching from a roof-mounted magnet antenna to a flexible whip antenna that I plan to mount to my front ARB. I plan on drilling a new hole into the bumper for the mount, and my question is whether it will make any noticeable difference in performance if I mount it near the front corner, versus mounting it in a more central location on the bumper.

By the by, it's a 4' whip with a spring and quick disconnect, plus 18' of cable.

[gary in ohio]

I'm in the process of switching from a roof-mounted magnet antenna to a flexible whip antenna that I plan to mount to my front ARB. ..
..
..
whether it will make any noticeable difference in performance if I mount it near the front corner, versus mounting it in a more central location on the bumper.

By the by, it's a 4' whip with a spring and quick disconnect, plus 18' of cable.

If the SWR is good, the antenna is good for CB. Your not going to talk for more than a few miles anyway. Roof is best everything else is a compromise. You will have a better signal forward and off to one side than to the rear but more than likey you will never see the difference.

[mag232]

Thanks for all the info in the thread.

I bought the 8800 and the Diamond 2m/70 cm antenna. I'll mount through the roof, no problem. I'll also want a CB and through the roof antenna. I haven't found a simple answer to the question of how to best install 2 antennas. I can put either mounts close to the center, but how do i optimize placement for both Ham and CB antennas? Thanks for any info....

[DaveInDenver]

Thanks for all the info in the thread.

I bought the 8800 and the Diamond 2m/70 cm antenna. I'll mount through the roof, no problem. I'll also want a CB and through the roof antenna. I haven't found a simple answer to the question of how to best install 2 antennas. I can put either mounts close to the center, but how do i optimize placement for both Ham and CB antennas? Thanks for any info....
There isn't really anything to optimize them so much, it's more a matter of keeping sufficient spacing. The antennas must NEVER touch, that would make for a couple of very unhappy radios. As long as you keep enough space between the two, they'll basically be ignorant of each other. Personally I find HF antennas too tall for the roof and moved my CB antenna back to the bumper. Even a short CB antenna is gonna be about 4 feet tall and I got tired of it smacking everything. For the ham antenna I have a stubby dual band that I use on the trail, it's only 19" tall and has a spring.

[xcmountain80]

For the time being I have eliminated use of my cb, the ham took over the antenna position on the bumper and I have a mag mount coming for the roof (little redundancy never hurt anyone). Keep thinking of where the cb antenna will be relocated. Was thinking of drilling a hole on the opposite side of the bumper and placing it there. Not related my diamond antenna recently folded (in case you go in to a garage of tree branch) going 85mph on the interstate. I wasn't sure if it was gone gone but I stopped and it was still there just folded over.

Aaron