CB Antenna questions and pics.

[evldsl]

I don't believe that's true. A single antenna is omni-directional. Meaning it transmits in all directions equally. If you run one antenna on either side of the truck, the RF waves hit each other, and cause the propagation to change to a fore and aft bias (elliptical). Holding all other factors the same, this setup would give you "further" transmit/receive boundaries for the desired directions while traveling in a vehicle.

The antenna will use the vehicle also, let me explane it to you.

The single antenna is installed on the rear of the vehicle thus the strongest projection is forward due to the mass of the metal in the vehicle. If you were to install the antenna on the front fender you would get a stronger antenna direction to the rear of the vehicle,and with a antenna on both sides of the vehicle it becomes bi directional. The SWR meter ( I own the HP 5000 by Aries meters), is used to tune your c/b and antenna(s). There are laws that need to be met when installing a antenna. The most important is antenna cable length it has to be of a correct length between the antenna and the c/b and never under 3 feet and always measure your cable in 3 foot length's. If your c/b is 10 feet away from your antenna install 12 feet of cable this is the surest way to get a correct or close to SWR.

During the last 2 days I have been installing a Gallexy DX 979 C/B and a Magnaforce 350 amp in my 2001 TJ, along with a 5' firestick 2 this combo will let me get yelled at by every park ranger in California about turning down the power. I know that the amp only put's out 150w RMS but thats 400w PEP.

 

[BKunic]

Bellyscraper,



If I'm reading you right here, you're saying to have the antenna cable length atleast three feet in length AND in multiples of three, right? If you have an excess of cable, I've heard that you should NOT coil it, is that correct?



Bryan

 

[SCClockDr]

To bundle excess coax lay/fold the cable in alternating directions and tie wrap. Coiling alters the resonance and affects SWR and feedline Q.

 

[Udaloy]

The antenna will use the vehicle also, let me explane it to you. The single antenna is installed on the rear of the vehicle thus the strongest projection is forward due to the mass of the metal in the vehicle. If you were to install the antenna on the front fender you would get a stronger antenna direction to the rear of the vehicle,and with a antenna on both sides of the vehicle it becomes directional.

So do you think, considering a CB, not a HAM radio, that one antenna will transmit and receive further than a dual setup?

 

[ECappleman]

One more quick question guys.



Those of you mounting your antenna somewhere on the bed, are you still going thru the firewall to connect?

Also how are you routing the cable?



Thanks

 

[Spooled-up]

If you get up under the truck, you can see there is a "plug" under the floor of the storage area under the rear seats. You can pull one of those, drill it, install a rubber grommet, and route your cable into the cab that way, then under the carpet to the CB. I was able to use less cable this way.

 

[Crunch]

Those of you mounting your antenna somewhere on the bed, are you still going thru the firewall to connect?

Also how are you routing the cable?

I specifically didn't want to come through the floor plugs. I looked at them and figured that was asking for moisture to enter the truck. No seal lasts forever. I used a stakehole mount in the first stakehole behind the driver side. They routed it down the sidewall of the bed and strapped it to the frame, then came straight up the firewall and through a hole I had drilled in the clutch master cylinder plate. They attached the connector after it was through. I used a rubber grommet to line the hole and sealed it with silicon. I figured that a pass-through in the firewall would shed water instead of letting it pool. The standard 18' of cord was enough to get it to the center console.

 

[Rlamb]

In order to get the fore-and-aft directional effect, the dual antennas need to be one quarter wavelength apart, about nine feet at CB frequencies. That works on a big rig, but not our trucks. A single antenna is a better choice. If your antenna is well matched, the length of coax doesn't matter. Coiling it doesn't hurt anything.

 

[evldsl]

Bellyscraper,



If I'm reading you right here, you're saying to have the antenna cable length atleast three feet in length AND in multiples of three, right? If you have an excess of cable, I've heard that you should NOT coil it, is that correct?



Bryan

The best way is to at least ( minimum) have 18 feet between your antenna and the amp or c/b. If your installing a amp then a minimum and no less then 3 foot length's between the amp and c/b. you can coil the 3 foot length's but loosely. What most do is wind the cable out not roll it up.

 

[evldsl]

If useing a duel set up it's the best for 360 degree even send and recive and will radiate further, the single type is more directional depending where it's located on your vehicle. If the(1) antenna is it the center of the vehicle (mass) it will radiate evenly in a 360 degree range. Where if the single antenna is at the rear of the vehicle it will radiate more forward due to the vehicle body mass, remember this is magnatisim off a coil thus it will follow the most mass.

 

[ECappleman]

I've seen "non-grounding" antennas, are these any good?

Firestik makes one of them.

 

[Spooled-up]

GoCarGo,



Do you have any pics of your setup? I'd like to take a look at it as it's one I never considered. The antenna mounting is what's keeping me from having my CB in the truck right now. Seems like the whip wouldn't interfere with the cab of the truck when backing into a garage, it would bend out of the way when going through a bank overhang, and it would get good reception too.

 

[ECappleman]

I just talked to a buddy of mine and he has an adjustable 85 watt linear amp he will give me.



If I use this, I need at least 3ft of coax between it and the CB, correct? Can you buy it that short, or do you have to make one?



When I bought this CB, I didn't know there were so many variables. Makes me re-think my decision, but the sales was final.

I'll get it set up though.

 

[Spooled-up]

Here's my plan. What do you think?

I'm going to mount a 102" whip antenna on my rear bumper. I will mount it on the drivers side of the bumper so the tailgate doesn't interfere with it. I'll have to drill the plastic cover with a small hole saw to make room for the antenna mounted directly to the metal of the bumper. To keep it from damaging the fender, I'm going to make a metal support that will be mounted in the rearmost stake hole pocket. I'll use stainless flat stock and extend it out to where the antenna comes up. The antenna will go through a hole with a rubber grommet in this flat piece and extend upward.



This will be a sturdy mount, it won't break when going through drive-throughs, and from what I've been reading on 102" whip antennas, they perform very well compared to most shorter antennas.



What do you guys think? Will the support mount that the antenna passes through cause any problems with reception or transmission? It will be about 1. 5 - 2 feet from the base of the antenna.

 

[bmoeller]

I A single antenna is a better choice.

It also depends on any trailer that you pull, if any. I pull a 50' bullrack (aluminum), and a single antenna is a joke to try and talk to someone very far behind you. I pulled it and ran a pair of fiberglass whips. Can get out now, and better reception.



On the Ram, I ran dual K40 whips on the mirrors. Got out pretty good. Have just one of the same antennas in the middle of my headache rack now. Works even better.

 

[BKunic]

ECappleman,



What don't you like about that Cobra you got? If you were doing it over, what would you get? Just trying to avoid any future regrets as I'm also getting ready to install a CB.



Bryan

 

[ECappleman]

I got the model I wanted. It has all the features I want, plus a cool back light for the whole face plate, with a dimmer switch.



I was just letting out some frustration. I bought it before I did any type of installation research. I thought it would be just "plug and play".



I have a large black tool box in the back, that stops about 3" from the side of the truck, and think I will use a side mount on it. Then I'll run an extra grounding wire to the frame. It already has large drain holes on the bottom and I could run a cable up thru that.



Maybe like this one with a 3 or 4ft black fiberglass rod.

antenna mount

 

[BKunic]

Yeah I know what you mean, it isn't exactly "plug and play. " I've learned alot from this thread. I'm thinking of putting the antenna in the left front stake pocket, running the coax in through the firewall and then wiring everything up. But something tells me that it'll take a while. Or I might just get lazy and have a CB shop do it. The whole thing would get done in 2-3 hours that way.



Where are you going to mount the CB itself, under the dash or ?

 

[ECappleman]

"Big Bob" on here sells mounts. I'll probably buy one of his.

There pretty cool, check them out.....



Mounts

 

[DDevine]

I have one of Bob's mounts coming in the mail Looks like it should work out fine.