If there was ever a time to read BEFORE taking action … than it is BEFORE doing a CB installation. The "modern" world of "plug-n-play" and/or "point-and-click" has literally sucked the common sense out of society. Come back to the real world please. Installing a CB isn't the same as putting together a swing set. You do something wrong and you might just burn out your radio in a matter of seconds. GO FORWARD WITH KNOWLEDGE!
Mobile CB never has been, nor can we ever foresee it as being plug-n-play equipment. I don't care what you have ever been told … you cannot just put a CB system on a vehicle and expect it to be ready to go. It doesn't matter if you put the exact same radio and antenna set up on the exact same type of vehicle ... if you don't put an SWR meter on your set up … you are flirting with an expensive lesson. Remember this ….
THERE IS NO SUCH THING AS A UNIVERSALLY PRE-TUNED CB ANTENNA . PERIOD!
If you read on a package that the antenna was pre-tuned … that only means that it was checked on a manufacturers test bench to verify that it was within the frequency tolerances set by the manufacturer. Ground plane dependent antennas MUST have counterpoise (ground plane) and unless you are driving a car that is shaped like, and has the exact same metal mass as the manufactures test bench … YOUR ANTENNA NEEDS TO BE SWR CHECKED AFTER INSTALLATION. And finally, if the packaging of one antenna hanging on the wall says that it has a tunable tip, that DOES NOT mean that the one next to it that doesn't have a tunable tip doesn't need to be tuned. The one with a tunable tip is just easier to tune.
This is a sensitive matter and you MUST get it right. How sensitive is this SWR thingy? So much so that if you move your antenna from one location to another location on the same vehicle … there is a very high likelihood that the SWR is going to change. Do not second-guess this process.
The reason you adjust the antenna is because you don't have a way to adjust the rest of the things that the SWR meter is seeing. I suppose you could take a sledge hammer and beat the vehicle up so much that the SWR would change but that is not something I would recommend or even try. The antenna is adjusted to compensate for all of the flaws that feed it and surround it. You wouldn't believe all of the silly things we have seen over the years. We get to hear all of that stuff because the antenna always gets the blame for bad SWR.
And something else … SWR meters are every bit as dumb as rocks. Too many people give them way too much credit. That is, some people actually think that an SWR meter can ignore everything except the antenna. Wrong! When your SWR meter is being used it is "seeing" everything in the area. This includes connectors, coaxial cables, antenna mounts, antenna stud mounts, the vehicle itself, and of course the antenna. And if your mother-in-law is standing close to the antenna, or your door is open … the SWR meter WILL see that and take it into consideration. There are two great forces in the universe … one is gravity and the other is magnetism. CB antennas can radiate a magnetic field that can be absorbed and deciphered by another receiver that is thousands of miles away. So if your goat is sleeping on the roof of your car … or if your neighbors are throwing a block party in the bed of your pick-up … you're gonna have to throw 'em out until you get your SWR adjusted.
Common sense rules! If we had the choice of packaging a cubic foot of common sense or a cubic yard of intelligence with our products … we would chose the common sense. Don't let its size fool you … common sense has more mass than intelligence!
Last Revised: June 6, 2006