How to install a CB radio.

These CB radios that fit into automobiles are not scary, nor are they a science. Well, they do involve a little science, but you don't need to know it, just how to use it.

Firstly, you are going to need a few tools and some basic materials to do the job.

You will need a pair of electrical pliers of some kind, some screwdrivers and probably an electric drill.

You will also need some automotive grade electrical cable (please, no household stuff!) in both red and black, at least a few feet of each. You will also need some wire connectors, or some means of joining wire like solder and an iron to suit. Some electrical insulation tape is also handy. And don't forget the all important 50 ohm coaxial cable to connect the aerial to the box. You can get this pre-cut to length with a plug attached  (best option) or off the reel and buy a plug to suit.. Add in a mount for said aerial and the aerial itself and that might just do it.

Got the tools and the stuff? Good, lets continue.

You will need to find somewhere to put the CB radio inside the cabin of your vehicle. Select somewhere out of the way, but still readily accessible so you can adjust the channel as required. You will also need to select a spot for the speaker/microphone to live. This should be readily accessible, and out of the way also, with the emphasis on accessible. Once you have chosen the appropriate locations, fix the radio bracket and microphone to wherever it is you decide to place them. If you have no bracket, still fix the radio in place, but remove it afterwards. You still need to make some connections.

After you have done with fitting the box itself, take a look at the back of the unit. There should be at least 2 connections you need to take note of. One of these is the power connection, it should be either a socket connection and wire/plug to suit or just two wires sticking out of the back, one positive, the other negative. The other connection is the aerial connection, this will be a strange looking plug about 0.75” in diameter with a small ‘hole’ in the middle of it. Anything else disregard unless you have plans to use them. They will likely be external speaker plugs, maybe another you need not concern yourself with.

Firstly, the power connections. You will need to get a red wire (as mentioned above) from the positive of your battery to the unit. Most times there will be a strange plastic tube looking thing in the radio wiring. This is a fuse, open it up and check if the fuse is there and alright. If so, connect the wire form the battery to the wire from the radio, making sure the fuse is still in the wiring. If there is no fuse, you will need to connect one in. Radio Shack or similar will have a suitable ‘in line’ fuse. Don't rush out and buy one right now, you may need other parts. To finish the power connections, take a black wire and run this from the negative radio connection to ground. A solid grounding point should be easy to find, something metallic and attached to the body of the car. You could also connect back to the battery if you so desire.

Next, the aerial connection. This is where the ‘special coaxial’ cable is required. It is different to household TV coaxial cable in that it is rated at ’50 ohms’ while TV cable is ’75 ohms’. I wont go into details, aside from make sure you get the 50 ohm stuff and buy the best quality cable you can afford. Poor cable makes a good radio bad and a bad radio useless.

You will need to measure this cable to a set length. I swear by 18 feet myself, but if this is impractical, a length can be selected in 3 feet intervals. For example 9 feet, 12 feet, 15 feet, 18 feet, etc. I was told 18 feet, and have had great results with that length. Pre-cut lengths with connector are available, as is ‘off the reel’ cable and separate plugs. Best to find a pre-cut cable if possible.

Run this cable from your radio (plug at the radio if you have it) to where you plan to place the aerial. (see below for further info on this) Make sure you have enough length at your end points to allow easy connection and also make sure the cable is not run tightly around corners and will not get damaged by sharp edges. If you excess length you will need to ‘hide’ it. Do NOT coil it up, simple fold it into a convenient length a stuff it somewhere out of the way. Tape it together if you have to, but don't coil it up. Keep the coax away from power cable if possible, and definitely away from the engines ignition system.

You have the coax in place, you will now have to take care of the ends. If you chose a pre-cut length that had a plug already on the end, then go to the next step. If not, place the plug on the end taking care to get it right the first time, as you have little chance to start again with that precise length. (hint, allow a few extra inches and take note of how much you cut away to make your plug connection. Then simply take the excess off the other end as required). Make sure the plug is attached well, but do not connect it to the radio just yet.

On the other end of the coaxial cable will be a ‘mount’ for your aerial. I recommend selecting a solid mount, but I hear the magnetic mounts work fine and are easier to place. If you use a magnetic mount, follow the instructions and leave it at that. If you use a solid mount, then you will need to find a place to put it. Select a place where there will be a large area of metal in as many directions as possible. On the roof is best, on the hood or boot lid is also acceptable. On a bumper bar is not a good idea.

The reason for this is you need a ‘ground plane’. Simply put, this is an area of metal that is ‘grounded’ with respect to the radio and aerial system. The larger the ground plane, the better the signal. And you should also try to make the ground plane at the same level as the base of the solid mount. From what I understand, magnetic mounts have their own ground plane.

Once you have a place, attach the aerial base and make sure all connections are good. Make sure the centre wire from the coax does not touch the ground, and the ground connection is well grounded to the car body/chassis.

Now what?

You should probably have an aerial right? I recommend that you find a ‘pre-tuned’ aerial to make life easier. These are tuned at the factory and should be ‘acceptable’ for most installations. They will not be perfect, but they should work. Simply screw the thing to your selected mount.

Now you have power wires run and connected, the coaxial cable at the radio but not plugged in and the base/mount attached to the car and an aerial attached to the base. You are almost done!

To finish, you should try and beg/borrow/steal or just buy a ‘SWR meter’. Cheap ones can be had new from around $15 or less. But if this is a ‘set and forget’ radio, better to try and borrow one from someone. To tune the aerial would take up alot of space and I cannot describe the process better than I found on the web from an aerial manufacturer known as ‘Firestik’. Simply click to http://www.firestik.com/Tech_Docs.htm and read up there. Print out what you need and go from there. I cannot describe it any better than they have, and even used these instructions myself. An invaluable source of information right there, so good in fact you might wish to read up there before you do anything!

So, you have made sure everything is connected, attached and tuned. If all is done correctly, you should have a working CB radio.

I guess you should go talk to someone then huh?
 
 

Schtoo