1989toy4wd

Okay, does anyone have thier cb antennas mounted on thier bumpers? I am thinking about getting a 3 or 4ft firestick to replace my 8.5ft whip (hits too much stuff!) But I dont want to mount it in the bed like I have now, It looks weird! I am also going to get the small cobra cb to mount in the old ashtray spot (I fried my expensive cb not grounding the antenna!).

What would be the best way to do it? I have marlin front and rear tube bumpers, I was going to see if the antenna has enough threads showing to just drill though the bumper and mount it on a spring.

Also I am going to get a cheap temporary aux fuse box (i am going to order a blue sea one) , do some wiring, wire up some relays/switchs, for lights cb, etc(have everything wired up so when I get ready to do lights I dont have to run wire again)!

Actually would anyone be interested in a wiring build up thread??

scuba

You need to have a nylon washer "isolating" the antennae from the bumper..Or else your whole truck is an antennae, like before..

BigBluePile

iTrader: (3)

Yup, like these:

swapped89

so your not supposed to have the metal part of the antenna touching the metal on the truck?

scuba

Nope.

The antennae needs to be grounded though...

mr toytech

being that my hole family is truck drivers ive always been told that cb antennas should be mounted as close to the center of the vehicle as possible. that is why all the big trucks have them on the door mirrors. because no matter what, the antennas reception is effected by the vehicle. mine is mounted to the front of the bed on the drivers side. and you should have it tuned after it is mounted.

96redtoy

well here is mine not a fire stick

not the greatest pic also but you can see it---

abecedarian

Think about it for a moment- every circuit has a separate supply and ground.
Having the 'supply', in your case the signal from the CB, connected to the 'ground', again in your case the bed of the truck, results in a short in the circuit.
In short (pun intended), you are cutting the signal off before it gets to the antenna.

So if you look at the cable from the CB (RG-58 for most, RG-8 if you're hardcore running linear amps and such) you'll notice that the cable has a center conductor (or possibly multiple 'twisted' conductors) surrounded by an insulator (hmm what's an insulator for?) and a braided shield / ground (and maybe even a foil wrap around the central insulator and possibly around the braid), then the exterior insulation.
The center conductor of the coax connects to the antenna and must be insulated from all surrounding metal, hence why Scuba said you need nylon washers, etc., and the 'shield' or braided wire needs connected to the metal surrounding the antenna.

One thing to consider is what's known as the 'ground plane' effect. In essence it means that the signal to or from the radio will be stronger in the direction of where the ground is. Bear with me a moment here... an antenna mounted in the middle of the roof of the cab will emit stronger signals towards, and be more receptive to signals coming from, the sides of the cab since the roof of the cab is a short but wide rectangle. Get what I mean? It's because the 'ground plane' extends left and right more than it does front to back.

Okay... now ... here's the basic way to think about the antenna: it is a light bulb and you want to be seen from, and be able to see, as far away as possible. Anything that interferes with the light coming from the bulb is a bad thing. Metal is a reflector, so anything in front of the signal reflects the signal the other way.

1989toy4wd

Wow abe, you are a smart man!! You too scuba!

I have a spring on the whip, and there is a nylon washer on the bottom of it. But the antenna wasnt grounded on to anything, so I think thats why it burned up my cb!

I am actually just thinking about a magnetic mount now...I mean I am not going to really use the cb to talk to truckers, just on the trail! But I think it would look better to have one mounted somewhere!

Oh and I ordered a blue sea fuse box...anyone want to see a writeup on cleaning up wiring, wiring relays, etc??

abecedarian

A nylon washer insulating the spring from the metal you have it mounted to? What about a washer insulating the bolt on the other side of the metal? The bolt should be connected to the center conductor of the coax, and the coax 'shield' should be connected to ground.

As for magnetic mounts... they're okay for temporary use but I wouldn't use one in a situation where I may be alone and need to talk over a "distance". Think about it, in the context of what I said above about the ground plane.... A magnetic mount doesn't guarantee that the antenna mounting point is grounded properly and consequently affects the 'ground plane'.
It's hard to describe but if you can imagine "waves", you want the positive side of the wave leaving at the same point the negative side of the wave is. After all, RF signals are comparable to AC voltage, travelling in a wave, and if there's a delay in one side of the wave, it affects the voltage.
Having the ground X feet away from the CB when the signal source is Y feet away is not a good thing since they will be out of phase at the antenna (unless you're really good at installing your coax).

turborich

The folks in your family are 100% correct! The best place for a CB antenna is dead center on your roof. 96redtoy's antenna is a base loaded antenna & that is the worse place to mount an antenna like that. If you are going to mount an antenna on your bumper like that then you need a top loaded antenna otherwise your SWR's will be way out of whack & you will be lucky if you can transmit or receive more than a 1/4 of a mile. Don't get me wrong, I like where the antenna is mounted & li looks cool there but it just won't work like it should, Maybe 25% at best. When you mount your antenna you want to make sure that there is no metal near the sides of it such as the bed, tailgate, fender, cab, etc. Unless you don't care about talking very far, then you can put it where ever you want. The best place to mount an antenna on our trucks would be the roof, then the next choice would be to have an (L) type of a bracket sticking through the hood/fender crack & attatching the antenna there, after that I would say centered behind the cab or twin sticks on both sides of the cab (they need to be top loaded & at least 2 or 3 feet higher than the roof itself though & you still may only get about 75% out of a set up like this. You will also need an SWR meter to set you standing wave ratio. If it's not correct then you will be losing a lot of the power through the coax, & in other places. You could even end up burning the finals out the the CB.

The best antenna is the 108" stainless whip but let's face it, they are just too big & hit everything. Next would be the Wilson base loaded antennas such as the Wilson 1000 (goes on the roof) None of the other fire sticks or similar can compare but than again you can't always use a Wilson base loaded antenna such as on big rigs where you would use a stick antenna.

I was really BIG into CB's years back & had my moblie radio talking loud & was running a lot of power (Linear amp) My base was loud as well so I know what's up with Cb's. Just some info incase anyone wanted to know how to run an antenna correctly for the best performance.

abecedarian

Most truck drivers mount the antenna off the mirrors for clearance.
I'd hate to have to replace an antenna after every bridge I pass under...
Oh and let's not forget that most truck drivers utilize 1/4 wave antennas and a co-phased configuration with one antenna on the left, and one on the right, and tune the system to radiate properly without negatively affecting the impedence.

algranger

YEah the trucks cant have their antenna's taller than the trailer.

Dual antennas do wonders i would rig duals up on the hood. Ideally you would have at least 1/2 of the antenna above the highest point on the truck i stuck duals on my rear bumper on my camping/daily rig and my trail rig has a single (soon to be duals after seeing the results) on the front quarter panel.

You want to ground your antenna straight to the battery to avoid the noisy circuit. I think you can get an inline filter as well.

And i would recommend using springs mounts with the Firestick antenna's they will crack instead of whip around if they are on a stud mount.

abecedarian

ground the coax (from the CB) at the same point (but insulated from) the antenna mount.

Ron Helmuth

yes I would love to see that kind of writeup on the blue sea product -even though I am in a 3rd gen. I like to see real user info.

I wonder what you all think of Firestick mounting in the ARB bumpers? I am leaning towards dead center ....? Based on your distance comments...

Or is a corner location fine if I want to listen from long distances but don't necessarily care about talking back that far?

There are a lot of considerations in putting together a good setup... I got my antenna and am about to get my spring, now I need to get a nylon washer it sounds like, whew is there a newbie guide to this type of thing?

I would ground to the frame -would that not be just like to the bumper itself?

abecedarian

Listening (receive / Rx) isn't as sensitive to antenna mounting as talking (transmit / Tx) is, but still exhibits a tendency to be sensitive to the antenna mount location.
Overall, high and centered is the best location.
Low mounts put the body of the vehicle into the interference area and limit transmit and receive sensitivity in those directions.

Going back to my lightbulb analogy, if you can see it, you can talk to it.

Philurfriend

Although it's not always practical, you will always get better antenna performance when mounted top and center of your vehicle...
however, a different effect will be achieved when 2 antennas are used instead of one; there is a specific reason that truck drivers use opposing antennas...not always what everyone wants.
-Phil-

olharleyman

If I was you I would mount it center of the bed and behind the cab then as for the height and hitting you can get a hook set up for the tailgate and hook it when you are drive around like the ARMY do with theres.

when out on the trail release it so you get the height needed to to receive and transmit you can also get a tennis ball and cut a small hole in on opposite ends and slide the ball down to the area where it looks like it may hit the back of your cab to keep it from hurting the paint and also remember to set your SWR and use 18 ft. of coaxial 50-75 omh with a pl 259's on both ends.

Also Remember uneven 3 ft. lengths is what is going to get you the closest 1 to 1 match between the radio antenna i.e. 18, 21ft. and with the extra cable loop it side to side for best possible SWR match.

Ron Helmuth

thanks for the input. It's not practical for me to go center roof permanent mount.

thanks abecedarian for that light bulb analogy that is helpful

olharleyman

No man I think your missing the point

You mount it on the bed rail behind the cab in the middle not on the roof and you will get the same effect as mounting on the roof if your antenna is above the roof of the truck.