COAX Cables

In this, our first column, I would like to begin by talking about your drive train—radio drive train that is—the coaxial cable (COAX) that gets the power from the radio to the antenna. Like any reliable drive train, it must be free of water, rust and kinks and must be regularly maintained. After all, you wouldn't consider operating your vehicle with water in the diffs, rusty U joints and a bent driveshaft. The same applies to the COAX. Once water seeps into the core of the COAX, its characteristics change. COAX is comprised of a center wire covered in a dry white insulator that, among other things, keeps the finely woven braided outer shield at a precise distance away from the core. Water seeping inside or being crushed from a hood or door can electrically change this finely balanced structure.

The connections at either end are like your universal joints. If they are rusty or corroded, you are going to have problems. Make sure all connections are clean. This may require disconnecting the lugs at the antenna end and cleaning with some fine sandpaper. Do not use steel wool as even one fine strand left behind may short the connection. Once clean, dry and reassembled, keeping air and water away from the connection and down the COAX is the goal. Silicone works well as long as you are sure it is covered completely and not going to trap in any water that manages to seep in. Silicone may also make it hard to do routine inspections and maintenance. Vaseline, or grease, can be used but is messy and needs to be reapplied often. However, you may want to use this less permanent method as future articles may lead you to change your present set up.

If your COAX is exposed to the elements, poorly maintained or of unknown origin, replace it. When installing COAX inside the vehicle keep it away from any onboard computers and avoid running it parallel to speaker wires. It should not flex or move with every bump in the road and no crimping, squeezing or kinking is allowed. The length of COAX in an off road vehicle is generally irrelevant. Do keep a foot or two of extra COAX at the antenna end for redoing the lugs or if you decide to change things around.

At the antenna end, the lug attached to the braided shield must electrically connect with the metal of the vehicle. The lug on the centre conductor must electrically be attached to the antenna and isolated from ground, like the antenna.

If you decide to put the connector on the coax yourself, refer to the diagram supplied. Keeping things really simple, you can buy the pre-configured CB COAX from Radio Shack in the $15.00 range. That works out about a buck a year for its maintainable life. Don't we wish all drive trains were as cheap to replace or as easy to maintain!

Future topics will include radio and antenna selections, mountings, wiring, external speakers, microphones and more! Together, we will work to whip your CB system into shape as soon as possible.

Other Issues: Coax cables | SWR Meters | Antenna Mounting
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