I am looking to mount a cb antenna on each mirror like the big trucks do. I have the trailer tow mirrors and was curious if anyone knew of a good way to this without messing up the mirrors.

 

i just saw a SD yesterday that had them. i tried to get a good at them (driving down the highway) and it looked like he just used a pair of those mounts that are used to mount to a tube.

 

Problem with mounting to the tow mirrors is they are plastic and provide no ground for the antenna. Yeah they do sell antennas that require no ground..but they do not work nearly as good as a good grounded one. Yeah you can run a seperate ground to the nut on each mount but that doesn't work well either. The main thing is getting that SWR down LOW. HIGH SWR and POOF there goes your radio. They look good on the mirrors but do not perform as good as a well properly grounded antenna.
What i did was mount a mirror mount in the corner of the cab and run the coax down behind the bedliner and out the rubber gromet behind the cab and then in thru a rubber groment in the floor of the truck into the cab. I then used a wilson silverload antenna. Hooked everything up and checked SWR's and they were flat..didn't move at all. The radio and antenna work perfect.

 

Mine are on the mirrors and are basically for looks as of now. I used the aluminum mount but had to get longer bolts to fit the width of my tow mirrors on a 2001 SD.

 

Mirror mounts are not the best thing, unless you are using west coast style mirrors. Antenna proxinity to the cab can affect VSWR and screw up your pattern.

The key to getting a good working antenna on your CB is to get the antenna up as high as possible, get the lowest VSWR reading and use the biggest ground plane you have. Ideally the antenna should be in the center of the ground plane for the best pattern. Also, full size antennas work the best. A 108 inch whip is the best antenna to use on a vehicle, but the hardest to mount.

The best solution as far as performance would be a 108 inch whip (or 102 inch with 6 inch spring) mounted dead center on your roof. It's also be the goofiest looking antenna you've ever seen.

Bed corners are OK, but the close proximity of the cab to the antenna can cause eratic VSWR readings as the antenna moves in the wind, plus will alter the transmit pattern.

Dual mirror mounts work well, they tend to shoot the beam patterns in front and behind the vehicle, performance is worse to the sides of the vehicle.

 

So what do you recomend as the best CB antenna to actually mount, seeing as how the 108 inch one isn't really plausible

 

You can mount an Antenna Specialists M125 in the center of your roof...or just to the rear of center for the best omni-directional coverage. You have to poke a 3/8 hole in the roof, but there are rubber grommets available that will seal that hole when you trade/sell the truck. They work really well. I used to sell,install CB's for a living, back in the day.

EDIT: Well, it seems that A/S is no longer in the CB antenna business...ummm, sign of the times, I guess. There are other brands that work as well (or better) I hear, I just haven't used them. I'd try the K40 models. They have roof mount AND magnet mounts.

 

I would probably go with a Firestik antenna or a K-40, mounted just opposite of the radio antenna on the driver's side cowl.

http://www.firestik.com

If you're afraid of drilling a hole, go with a 3/4 inch right angle bracket mounted between the fender and the hood, then use a Wilson antenna with an NMO style mount.

 

Using the idea of centered mount.... I've used a wilson 2000 with a long bottom pc mounted to the bed rail in the middle of the bed. ( Right behind the sliding rear window) to place the bottom of the load as close to the roof of the truck as possible. The wilson come with 3 or 4 diff bottoms I think the 24" worked best.

Just wondering... What kind of radios are you super truckers using?

 

I would strongly suggest that you forget the mirror mounts and buy a Wilson 5000 antenna. Make sure you use an SWR meter to get the SWR's as low as possible. It makes all the difference in the world as to what range you will get out to and recieve. Like another poster said you can also damage your radio if they are too high. The antenna will use your roof top as a plane and you will want to mount it as close to the center/middle as possible.

I drove my own big rigs for a number of years and got about as far into mobile CBin as you can get. If you want some good tech guys to talk to or you need to by a Big radio go here. These guys have great service, product and they know their CBin. http://www.pacetronics.com/

 

FORGET the mirror mount. Unless you want also install some heafty ground strapping. Also the antennas have to be about 1/4 wavelength apart to provide the best efficiency. Also SWR doesn't always tell the whole story. Yes it should be low.

The best place in in the middle of the roof with a NMO mount. I have a VHF/UHF "ham" radio antenna there. It's about 40" tall. I know CB/HF antennas are larger and the roof may not be the best place.

Check out this site. I know he mentions Ham Radio installs but a LOT of it can also apply to CB'ers. www.k0bg.com

Bob

 

This is the bracket I mentioned above. A lot of companies make them. You drill 4 small holes in your fender on the inner lip (between fender and hood, then mount this. The antenna (3/8 inch or 3/4 inch mount) goes in the top hole above the fender.



If you use this type of bracket, use star washers on the body mount screws to lock it in and bite the metal for a good ground.

 

Another alternative is this type of antenna, an AM/FM/CB combination antenna that would replace your AM/FM antenna.

http://www.afcoelectronics.com/afco-...er-antenn.html

They will not be as efficient as a dedicated CB antenna, but are easy to mount and mask the fact that you have a CB in your truck.

 

Also, let's talk about antennas.

You'll see 1/4 wave, 1/2 wave and 5/8 wave mentioned. A 1/4 wave antenna is 108 inches long, either eletrically or physically (108 inch whip). The shorter antennas you see have coils to make them 108 inches long electrically. 1/2 wave antennas are 216 inches, 5/8 wave are 270 inches. A 1/2 wave antenna will show gain over a 1/4 wave antenna. A 5/8 wave will show gain over a 1/2 wave. Coils (also known an cans) used to physically shorten an antenna are detrimental to the pattern. Therefore, a 5/8 wave antenna with a coil will be roughly equivelant to a full size 1/4 wave antenna.

Antennas make gain by squashing the pattern of the antenna. They try to focus the power at the horizon instead of equally in every direction. Additional gain can be found by focusing the power in one direction (beam antenna). Mirror mount trucker antennas tend to focus towards the front and back of the vehicle.

When you examine gain figures, you will see dbi and dbd. Dbi is decibels gain in reference to an isotropic source. (An isotropic source is a theoretical model antenna with a perfect distribution pattern in all directions). Dbd is gain compared to a dipole (or 1/4 wave antenna). 0 dbd is equal to 2.7 dbi. So, if an antenna claims it has 2 dbi gain, it really is worse than a 1/4 wave antenna; it would have -.3 dbd gain. Point is, just be careful when you see gain figures, dbi gain and dbd gain are not equal.

Decibels can be confusing, it isn't like horsepower. It's a unit of gain or loss. Roughly, 3 db gain doubles your power, so if you transmit 2 watts and have a 3 db gain antenna, your effective power is 4 watts. 10 db gain multiplies your power by 10. 2 watts into a 10 db gain antenna equals 20 watts effective power.

Vehicle bodies distort patterns. An antenna mounted on one vehicle will behave different on another. Just because your buddy used a K-40 and it works well doesn't mean it will work well for you.

 

"Just because your buddy used a K-40 and it works well doesn't mean it will work well for you."

...but, if it's the same (type) vehicle, mounted in same location, same transceiver, all mounted CORRECTLY, chances are it will act exactly the same.