CB Install

I saw a post, a few minutes ago, and wrote a book in response. I hit submit and the post was gone! To save my hard work, and to share with some that might find it useful, here it is...

The first thing you need to do is ask yourself what you are trying to accomplish by installing a CB...

1) Just being late 70's cool?
2) Mainly just for listening?
3) I'm a talker and I want to be heard? (or hear-ded in CB lingo).

Assuming #3

Antenna (the most important thing is location location location)

Get a base loaded antenna (K40 if they still make them) and install it in the middle of the roof of your XJ. I would remove the dome light and drill a small hole about an inch behind the dome light housing. This will give you room to run your coax.

Why the center of the roof? Radiation pattern. If you place the antenna at any of the four corners the radiation pattern will be in the direction of the most metal. Passenger side rear will radiate toward driver's side front. (This is a good pattern for talking to people further up the road)

With the antenna in the middle of the roof, you have a higher antenna, and the radiation pattern will be more omni directional (a circle). This means you should have the same signal to anyone no matter what direction they are from you. (Good for out on the trail)

The next thing you want to do is buy a good radio. Cobra's were good radios but I don't know since Uniden bought them. I would recommend the 148(GTX?). It should be a little over $100 ($150?) and it has the addition of SSB (Single Side Band). Single Side Band makes you sound like a Rebel Alliance squad member attacking the death star, but more importantly it will increase the range at which you can communicate. No one that is serious about radio communication uses AM, with the exception of aircraft. The other nice thing about this radio is it has a Mic gain control. Important if you are in a noisy jeep, or stopped and you need that extra punch. (Double check but I believe it has a Mic gain control) If not you can always get an amplified microphone later.

Next mount your radio up high. Remember the radio won't work very good if it is submerged. If you can stand it mount it on the ceiling in the middle. It will be up out of the way (except for your head) and the coax run from the radio to the antenna is very short. A short run of coax means less power loss and more power radiated out the antenna! I read somewhere that a guy put a thin sheet of plywood between the metal roof of his XJ and the headliner board. He then screwed the radio bracket into the plywood, otherwise you'd have screws sticking out of your roof!

Mounting the radio up high like this is pretty cool and you just put the Mic bracket on the side of the radio. The radio is easy to see, operate and it is out of your way!

Power! Don't wimp out and attach the power for you radio under the dash. Run the power connection all the way to your battery! This will allow the radio to pull the maximum amount of current it needs to generate the best signal. Make sure you use the same size, or larger, wire that is on your radio. Run both the positive (red) and negative (black) wires to the battery, not just one.

To adjust your antenna you'll need a SWR meter. The Cobra 148 has a built in SWR meter that you can use in a pinch, but a real SWR meter is always best.

Adjust your antenna of lowest SWR on channel 20. This is the approximate middle of the band (channel 1 to 40).

You can check the SWR on channel 1 and channel 40. If it is higher on Channel 1 than 40 you'll need to make the antenna longer. If it is higher on 40 than 1 you'll need to make it shorter. As frequency increases the antenna length decreases. You are shooting for a SWR of 1.5:1, but you should be able to get it down lower. 1.5 is fine, and anything up to 2.0:1 should be fine. Fine as in it won't damage your radio, but you'll be losing power radiating out the antenna. I seem to remember it is a 60% loss, at 2.0:1 but don't quote me.

You may be in a situation where you have to cut the stinger (the metal part of the antenna). If you cut, be sure and cut in 1/8 inch increments. You can't put it back once you cut it off!

Also if you have 10 or 15 feet of coax don't coil it up, cut it to length and SOLDER a new connector to the end. Don't use that solder-less crimp on crap.

These are just my opinions, and other people may have better one's. If you need more specific help just ask. You can see my own radio and antenna installation on my Amateur radio website, http://n5fnh.com/

My installation will be a little more involved because I'm using a radio that is made for HAM use and not CB.

cool write up. i got me some edgimication now. seriously though, thanks, i did learn something. i would like to install a unit in the jeep especially for an emergancy. now for the question. i allways heard they were illegal to use, but lets say for the sake of an emergancy were you would NEED some extra power (meaning distance to be heard or communicate), can i install a linear (spelling) for just that purpose? i know most CBs dont have the range but sometimes a cell has absolutly no signal at all. searching through the garage i found a couple of what i think to be 100 and 150 watt linears for a CB radio, and some old 23 channel CBs of course. i allways thought that citizen band was limited to 6 watts, so the range is limited. would it be a huge NO-NO to hook up one of these?

lol, huge no-no is an understatement. I would advise against installing one. Besides being very illegal the installation I outlined would change. The amplifier would need to be installed between the output of the radio and the antenna.

The power output on your CB is 4 watts (max).

If you MUST install a power amplifier I would keep it simple 100 watts. Remember when you double your power output you will see a gain of about 3 "s" units. This means if you go from 100 watts to 300 watts your signal would go from a 3 to a 6.

If you go from 4 watts to 100 watts (running CALC now...) that is 25 times more power!!! To see the same increase (relative) in signal from 100 watts you'd have to get a 2500 watt amp!!!

100 watts is easy to run from a car battery, etc... This is the power output from the radio that I have installed in my Jeep, note from the radio, not a power amplifier.

A common mistake people make is spending all their time and money on the power amp and not the antenna. The antenna will make a big difference. Remember you can't communicate with someone if you cannot hear them.

awesome write up, you taught me alot sensai!

that's an extra class license right

lol not me. I got my Novice license back when I was 16, and I was a General class by 17/18. I stopped there. Who knows, maybe Extra some day!

Is it worth getting a radio w/ sideband? The people you talking to need sideband too. Does it get you anymore transmit distance?

A good CB will cost you nearly $100. A good CB with SSB may cost $150. It is a small price to pay to give you the additional ability to transmit over a greater distance.

AM the power is used to develop the constant carrier. In SSB (Single Side Band) the power is used only when you talk. I seem to remember you can get 12 watts PEP when using sideband, over AM. That is 3 times the power you get using AM, so your power output triples. Again that would be like going from a 3 to a 6, or 0, to 3 on a signal meter.

Yes, a very good question, both parties must have SSB, but keep in mind the CB radio does both AM and SSB.

In amateur radio, AM was used over 60 years ago. Occasionally you will hear someone using AM, but it is really more of a special situation. Easily 99.999% of High Frequency (HF) radio communication is Single Side Band.

Frankly if you guys really want a great noise free way to communicate get your Technician license and use 2 meter FM radio. The power output on a typical $150 2 meter radio is 50 watts. The antenna is about 1 foot long.

You have the added benefit that when you aren't on the trail you can use repeaters to talk to people 20 to 40 (or more) miles away, and it is as clear (clearer in some cases) than using a cell phone.

They have removed the Morse code requirement for licenses so all you have to pass is a multiple guess test.

CB will be what most people have so of course that would be the best way for you to communicate with others on the trail, but HAM radio might be a great alternative if you and your buddies what a more "private" way to communicate.

With the radio I have in my Jeep I can speak to people in other states, and on occasion other countries. The sun spot cycle is at it's low, so the ability to communicate over great distances doesn't happen as often, however the sun is on the up swing so this will ability to communicate will become more and more common. If you were ever interested in HAM radio, now is a very good time to get in on it and enjoy the next 11 years of the up side of the sunspot cycle.

I have about a 1 hour commute in the morning, so the radio gives me something interesting to do while others look on and marvel at my pretty Jeep.

okay can i get some more tips on this whole cutting coax?

i need to drill the hole to get it to the outside of my hatch and if i can just get the wire thru my whole will be 20 percent of the size id need with a whole connector on the one end. thus being alot more clean looking and a smaller hole and grommet!

thanks
ima CB noob but someone in my club already offered to tune it for me

Ok a quick search on that thing you "kids" call the Internet and I found this...

http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/SolderCoax.htm

I must admit I've never used a butane torch like this guy uses, but it isn't a bad idea.

This write up makes it look a little overwhelming, but it is good information.

Frankly I started putting connectors on coax when I was 14 years old. I used a kitchen knife, soldering iron, and short pants! I can still remember the smell of burned hair and skin! lol

A few notes:

It is illegal in all cases to install a power amplifier in a CB installation. Period. End of discussion. No wavering. You are stuck with 4 watt of power output, make the most of it. I'm not saying that because I'm an icehole, I'm saying that because it is the law and we don't cover illegal activities on the Forums.

Most folks will have no use for CB based SSB. SSB has fallen out of use by the CB folks because of the cost of the radio does not justify the use they get out of it and chops up the adjacent channels. Sure back in the late 70's it was big, but not now. CB use on the trail is on AM, CB use on the road is mostly on CH19 and is on AM. IMHO, save your money for Jeep parts

Most Jeep folks will not be using RG8 into a PL259 connector. They will be using RG-58 (Single antenna) or RG-59 (for co phase installs). A solderless connector will work fine for most installs. If you do go that route, I would use the solderless connector on the inside of the Jeep. Soldering a PL259 with RG-58 adapter is not all that complicated, but takes a high heat iron and some patience. Radio Shack has solder and solderless PL259 connectors http://www.radioshack.com/product/index.jsp?productId=2103249

I strongly advise against the ball mount on the 1/4 panel for most installations. If you off-road, you will scrape it off. If you don't, most CB antennas are not high enough to overcome the shielding of the vehicle, and will suck in performance.

Some antenna installations require a certain length of coax. If you buy a kit, don't automatically cut off the excess for a clean install, your antenna may need that to get a good "match". Seems to me that the "stick" 5/8 wave antennas are the worse at this.

That covers the CB bit.

For more information on becoming an Amateur Radio Operator, I have never considered myself a "Ham", check out the Amateur Radio Relay League website at http://www.arrl.org. Amateur Radio is more than just operating an appliance, it is a multi-faceted hobby all by itself, much like Jeeps. The test is simplified from what it used to be. There are books, sample tests on-line, and your local Amateur Radio Club most likely has a "Class" to prep you for the exam.

That covers my advertisment for Amateur Radio.

As for alternative communications on the trail, I also carry a GMRS radio. I found that FRS (Family Radio Service) and GMRS (General Mobile Radio Service) "Walkie Talkies" were cheap, portable, and if you managed to drop it in a mud puddle, cheap to replace. FRS= No license .5 Watts. GMRS=License fee, 5watts on shared FRS/GMRS frequencies.
So, in our Club we use FRS/GMRS frequencies. No fuzz, no skip, and easy to use. Above all, no install to play with. Most carry about a mile or so in the woods.
Our club members either have FRS, GMRS, or both CB and FRS radios. Some carry a pair of radios for that person who is new to Jeeping and has no radio.
Of course I tried to convert the Club members to Amateur Radio Operators first , but when that failed, the FRS/GMRS radio thing works reasonably well for the trail.

Ron
WB9YZU

Thanks Ron that is a good point about the ball mount.