Could of quick questions for the CB experts:
1) Are the triple mode antena or converters worth a shit? Ie "convert your AM/FM radio antenna for use with CB)
2) If as I suspect the above aren't worth a shit(ie the $20 I spend), what is the criteria for mounting a CB antenna? I've got an entire flatbed of area to play with.
3) I keep seeing "use quality cable". What is the definition of quality cable?

Yes, I searched. I found one thread on CB's that covered some of the info I was looking for but didn't have anything to say about the dual mode antenna's, location, or what is quality cable.

Thanks in advance for any useful info,
John

Tri-band antennas suck.

A 9-foot whip would work well mounted to the center of the flatbed. But, this is unrealistic. I would probably go for a mag mount wilson 1000 mounted on the roof of the cab.

Quality cable is at a minimum RG-58. For cable runs of 10 to 20 feet, all you really need to be concerned about is that the cable is at least 95% shielded (the outer braid rating). Spending more $ beyond RG 58 is not really needed for cb frequencies.

Originally posted by J-Bone
A 9-foot whip would work well mounted to the center of the flatbed. But, this is unrealistic.

Unfortunately, a tall whip is out of the question for me. It becomes a weapon during any serious type wheeling.

I had one on my FJ40 for about 5 months and while wheeling, I had a nice clear path around my rig because of the whip.

Originally posted by J-Bone
Quality cable is at a minimum RG-58. For cable runs of 10 to 20 feet, all you really need to be concerned about is that the cable is at least 95% shielded (the outer braid rating). Spending more $ beyond RG 58 is not really needed for cb frequencies.

Does the RG-58 define the quality of the cable? I thought that merely defined the method/style of cable creation(ie type of core, core insulation, type of shielding, etc)

Also, the number I've seen thrown around for cables is 18 feet being "optimal".:confused:

on my jeep i have a 4-5' metal whip antenna connected to a walmart CB via a 18' coaxial cable. i thought the walmart CB would be just a temporary fix until i could afford a nicer Cobra radio. However i have been able to talk about 5 miles on it under good conditions.

in my truck i have 4' fiberglass FireStik II connected to a Cobra 25NWST via a 18' coaxial cable. The radio has been peaked and tuned to put out about 25 watts. i can talk around 10-15 miles out in the country with this radio.

both of my antennas are mounted using 3-way mounts that look like the following...
http://www.firestik.com/images/k-64.jpg
the one on the jeep is mounted through the body and the trucks is on the toolbox.


if this is going on a trial rig i would go with a metal antenna. they are a ton more flexable then any finberglass antenna. also 18' coaxial cable is the best length for tuning purposes. However, you have to be sure that you dont wind the excess up into a tight roll. It must be wound up in a gradual roll(ie 1.5-2' diameter roll). If it is wound tightly then it will interfear with reception.


for more information on firestick and other stuff go to firestik's (http://www.firestik.com/) website


EDIT: this is a list of FAQ's (http://www.firestik.com/FAQ.htm/)....some of your questions are answered

Well, if you must go with a shorty antenna that will hamper performance. The firestiks are relatively stiff, and you may be able to get one of a longer length than 3 feet. A co-phase (dual) set up will help, but to get the benefits of a dual set up, you need at least 60% of the antenna above the vehilce and the antennae space 9 feet apart.

The proper point to measure SWR is at the antenna feed point, which is right at the end of the coax. Because this is an obvious PITA, the way to "cheat" is to make your feed line 1/2 wavelength of the signal--18 feet in the case of the cb, usually for a non-tuneable antenna. The line length for anntenna runs MAKES NO DIFFERENCE for tuning SWR with a *tunable* antenna. The longer line is more lossy than a short line.

-----
Does the RG-58 define the quality of the cable? I thought that merely defined the method/style of cable creation(ie type of core, core insulation, type of shielding, etc)
-----

Right, but for short runs on CB freqs you don't need to go to air dielectric hardline. Go to RG-8 if you want. Save your cash a spend it on the radio. LMR 195 is good stuff, on the lower end of the spendy cable.

The coaxial cable has little to do with the frequency range, rather the power of the transmitter.

The antenna has ALL to do with the frequency range, IE CB BAND is what 11 meters?

so in esence the wave lenth of a CB FREQUENCY 29MHZ is 40FEET OR 11 METERS? long, this is why some folks run long ass antennas. Or you can use a 1/4 wave system, wich mimic's the wave output.

Wavelength (in feet) = 984 / frequency (in megahertz)

Cable slection is determined by your wattage output (TX)

Antenna slection is determined by your slect transmittal and receiving bandwidth. IE 25.01MHZ- 29MHZ (I believe)

ANYWAY, here's a link to a very "for dummies" help with stuff...

http://www.howstuffworks.com/question490.htm

my vote is for the wilson 1000 also
you won't be disappointed

The coaxial cable has little to do with the frequency range, rather the power of the transmitter.
-------

I was talking about line loss. There ain't that much, really, at HF (CB) freqs. You need to go up to 144 and 440 mhz to notice this condition for runs of 50+ (i.e. a base station application)

i vote for wilson as well, if you have roof space go with the base loaded model and metal whip 4 ft is plenty here. firesticks are ok, they are best when mounted on jeeps and other lower mount (bumper) aplications, thats the reaon for the top load design, dont even bother with a mid load antenna.

co-phase on a trail rig?? come awn !! duals make your rig radiate for and aft with little side reception, great for 18 wheelers on the hwy, not so great for the trail, same with front or rear mounts, you tend to get alot of directional power.

18 ft of good coax, dont worry about rg-58 bla bla, just make sure you get stranded wire not solid.

most of a rigs reception is in the antenna and coax, a cheap radio will work great if thats tuned (swr). but of course a good radio is better than el-cheapo. and while were here, dont waste your money on weatherband. weatherband is broadcast just like radio, once you get in the mountains, its gone.

Isn't the subject at hand CB Bandwidths?

[
I was talking about line loss. There ain't that much, really, at HF (CB) freqs. You need to go up to 144 and 440 mhz to notice this condition for runs of 50+ (i.e. a base station application) [/B]

Here is the skinny on antennas.

The most important (IMHO) is the mounting of your antenna. Always mount it in a place where it will be least likely to get ripped of. eg. Never mount it to the side of your rig.

Your antenna type is the most important factor. The frequency of CBs is about 27.000 MHZ (Nearest to Ch. 6) . A full wave antenna is about 36 feet. A 1/4 wave ant. is about 9 feet. In ant. const. they have "loads". A load is where the majority of the ant. is wrapped. eg. a 1/4 wave ant. that is four feet long will have nine feet of wire wrapped into it. It will be wrapped in such a way to have the "load" or the majority of the length in a certain position on the ant. For optimum performance, the load of the ant. should be level with, or just above the ground plane. The ground plane is the area of you rig that the ant. uses to transmit its signal. The ant. always uses the highest area for its ground plane.

Are you bored yet?

When you choose your ant. you want to know where you're gonna mount it. Where your ground plane is. The distance between the two areas.

The Wilson style ants. are bottom loaded ant. They perform the best when the load ( the white plastic round thingy ) is just above the ground plane. They work great mounted on top of cabs and such.

A straight stick or 1/4 wave whip (No load, the wire is just straight up and down ) will also work the best in this situation (Along with many others).

A "Firestick" style fiberglass whip has the wire coiled or loaded at the top. These work great where the ant. is mounted low but the ground plane is up higher.


Figure out where you want your antenna
Figure out your ground plane.
Figure out what you need.
Tune your SWR
Have fun.

alright Dennis....how do you decide your "ground plane"? on a truck would it be the top of the cab? The top of the bed? why would you want an antenna without a ground plane? what about on a jeep?




thanks for any info you can provide.......

couple questions.

what is a good trail cb. the only use for my cb is wheeling, i want something that can take a beating?

I plan on mounting my ant. to the back of my zuki (probably on my tailgate). is this good or bad, where is the "ground plane"?.

what kinda ant should i get and what is all this "tuning" all about?

any help would be great, all the cb stuff confuses me.

oh ya, and finally. how much would an amp help?

OK,
A couple of myths need to be disspelled here....

The length of the coaxial cable only needs to be whatever is needed to reach the antenna. Having a bunch of cable bundled up is only introducing more line loss.
The "18 foot" thing is not even an accurate 1/2 wavelength (what I've heard some say its s'posed to be). A solid-insulated (PE) cable has a velocity factor of 66%. Velocity is how fast the signal flows through the cable relative to free air space. This would make it 12 feet, and it still seems to work for people (in other words, it doesn't matter).

I have even experimented with this on properly grounded (mounted) installations and found no difference in SWR on a 5' cable vs. an 18' one and a 23' one (actually the 23' one was the tiniest bit lower due to line loss).

**Oh, why are many antennas sold with 18 feet of cable? The Mfgrs know this rumor is out there and they know their ant will sell better with 18 feet than if it has, say, a round number like 20.

As for "Quality cable", RG-58/U is fine for a stock CB on a trail rig. The thing to look for is good shielding (95% or better, as mentioned above). It will not damage anything if its less than that, though. The loss in performance usually isn't noticable except in higher end gear (SSB, etc.).

The solid-center cable also has a slightly LOWER loss than stranded cables. The solid stuff is NOT tolerant of frequent flexing, though (I.E., if your ant is mounted on your toolbox lid, DO NOT USE SOLID. use stranded). RG-58A/U is stranded.

RG-8X or RG-8M (a RadioShack equivelent) is another high quality cable with a lower loss than RG-58(A)/U. It is also stranded.


A 5' Francis HotRod ant is a very good choice for the trail. Its very rigid (won't flail around like anything with a steel whip) and is lightweight. It is toploaded. Requires no "tuning" if installed properly.

Simple, small, reliable, cheap, and with good performance, the Uniden PRO510XL CB radio.

http://www.rfwiz.com/images/UnidenCB/UnidenPro510_571pm.jpg


For antennan mounting, centering it on the vehicle provides the best performance (mine is on top of the rollbar). It will also work very well mounted on the forward edge of a truck bed, as long as its not a baseload type. Full length antennas are best here.
For use on the trail only, central mounting isn't overly important, as long as the SWR is good. I have seen many installations on the rear quarter panel that worked exceptionally well.
The key is to make sure the majority of the antenna's length is above the metal of the vehicle.
Do not mount it on a long extender bracket or similar, though. This will create a bad SWR and diminish the performance (I.E., don't mount it on a long metal bracket extending from the bedrail putting the mount above the cab. The antenna will work better if it has a solid body of metal immediatly under it).

Sorry so long, but hope it helps.:D


BTW, the frequency range of Citizens Band radio is 26.965 (ch1) to 27.405 (ch40) MHz.

Ok, I'm getting close to mounting my CB in the new K30 buggy. I basically have no sheet metal except for the floors. The cage/body "roof" bars are arranged like an asterisk (*) with 6 bars converging in the center (b-pillar hoop with halo and triangulated bars from the halo corners).

Based on what I've read here and elsewhere, sounds like the "ground plane" will be formed by the bars of the roof and the best mount will be in the center where they converge. This would ideally use a "base load" or neutral antenna. Is that correct? If so, what is the shortest (cheapest too! :D) antenna that will work well there for trail use?

If that is where the antenna should be mounted, I suppose it will need a quick connect to get it out of harms way in likely roll-over scenarios and such. Also makes fitting a canvas top more trouble. :(

Here's a good site with a lot of reading. Check out the FAQ's at the bottom.

http://www.signalengineering.com/ultimate/coax_basics.html

I bought the converter to use my AM/FM antennea as a CB ant., well it didn't work so great, so I bought a CB ant and used it as the AM/FM ant. and it works pretty good. Nothing to write home about, but it gets the job done.

Originally posted by BadDog
Ok, I'm getting close to mounting my CB in the new K30 buggy. I basically have no sheet metal except for the floors. The cage/body "roof" bars are arranged like an asterisk (*) with 6 bars converging in the center (b-pillar hoop with halo and triangulated bars from the halo corners).

Based on what I've read here and elsewhere, sounds like the "ground plane" will be formed by the bars of the roof and the best mount will be in the center where they converge. This would ideally use a "base load" or neutral antenna. Is that correct? If so, what is the shortest (cheapest too! :D) antenna that will work well there for trail use?

If that is where the antenna should be mounted, I suppose it will need a quick connect to get it out of harms way in likely roll-over scenarios and such. Also makes fitting a canvas top more trouble. :(

Your antenna will work fine on the rollcage. (After all, base-station groundplane antennas have 3 or 4 rods radially on the bottom. Thats a ground plane). It does not have to be a solid sheet of metal (Hell, when I was a kid, I had put a CB on my bicycle!, The bikerack on the back was enough to get a good SWR:eek: )
There are "Quick-disconnects" sold that will allow quick removal of a standard 3/8X24 antenna mount. Its a "push-down-twist-a-quarter-turn" mount.

Yes, stay away from those "AM/FM/CB" antenna things. They;ll work ok close in, but in a canyon, they may not even go from the front of a large pack of rigs, to the last.

Small, easy to use, and disposable... the Mini Wil. I think they also call them a Wilson 500. They are the Wilson antenna's you see on the back of cop cars. You can get a magnet mount Mini Wil at the local CB shack for $20. If you run a cage, just weld a 6" plate to the center of the top of the cage and slap it up there. You won't tear up the mount on a tree branch because it's a magnet; it falls off. It takes a helluva lot to make the thing fall down too. I've left scratch marks in the ground before the antenna popped off. I also got great range with it... 10 miles swinging the meter all the way.

http://www.c-bradio.com

they can set you straight. :)

they are in vegas and do all of the cb radios
for the local 4x4 clubs, they got linear amplifier
for your cb radio also!

Like "fryman" says get the "little Wil" or "Wilson 500" made by wilson they will get the job done....it's a 3ft. magnet mount & it's around $25.00. If you choose to run a fiberglass antenna go with a 4-5ft. length and mount it with a "sturdy" mount. If you go this route you can run a coax any length as long as it's in 3ft lengths....ie:9-12-15-18. Cheap/good radio to run/buy would be the Uniden Pro 510 it's compact/simple to mount & operate. I work in communications repair I deal with this quite often.....Good Luck