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Yukon's Radio 101

CB Shopping and Installation Basics

 

Index

What do I buy?
Spending too little
Spending too much
Installation
Antenna Tuning

"I just want to talk to a friend in the next car, what am I going to have to buy?"

    In the simplest and cheapest of installations, you're going to have to go out and buy 2 things: a CB radio, and an antenna.  If all you ever plan to do is talk more or less line-of-sight, from your car to the friend's car that you're traveling with, that's pretty much all you need to know.  Other than wondering where you'll mount the radio and antenna, and possibly worrying about "tuning" your antenna, that is.  BUT keep reading, 'cause I might change your mind about buying the absolute cheapest, no-name stuff you can find, or reinforce your reasons to do just that.
    Assuming you buy a decent CB radio, the most significant issues for you are what antenna to buy, and where to put it.  Also important is tuning the antenna if you want good performance out of the setup.  Some antennas aren't designed to be tuned, and are assumed to already be tuned when you buy them.  Sometimes, when you buy a radio, the store will be willing to tune it for free, or may charge a small fee to do it.  You may know a friend who can do it.  Or, since it's not really a big deal to tune an antenna to a reasonable level, you may want to tune it yourself by buying an SWR meter.  See Antenna Tuning below.  If you're not really concerned about total performance, you might feel like skipping the antenna tuning step.  Keep reading before you do.
 

Spending Too Little

    First of all, you may feel that you don't need good equipment because you'll only use it in the situation mentioned above.  Okay - what happens when you, driving behind your buddy, need to stop for a red light that he (or she) managed to squeak through.  There's a good chance that, if you have a really bad setup,  your buddy will be out of range before you can brake, get your hand off the shifter, and get your hand on the mike to tell them "Wait for me!"  In the worst radio setup I've used, the reliable transmission distance was measured in car lengths, not miles.  If a car passed one of us, and ended up between us, the bulk of the car presented problems for transmitting.
    If you stick to the name-brand companies like Uniden, Cobra, Midland, GE, and heck, even Radio Shack and Maxon, for both your radio and antenna, you'll pretty much avoid this rather drastic example.  No matter what others say about the quality of a given company's radio, they do have to make stuff that at least works,  otherwise they'd be out of business.  The danger area is if you choose to buy a walkie talkie instead of a real radio, or even one of those "emergency" radios that you keep in a plastic case under your seat until you need it.  If you're considering one of those, (and, yes, there are valid reasons to buy them)  you better read the section I wrote about the special considerations for them.
    Okay - so you're still not interested in spending any more than you absolutely have to for your setup, and you want to get the littlest, least visible antenna because you don't want it to affect the styling of your truck?  That's fine.  There's nothing wrong with this philosophy.  For some, that's all they want.  Just be aware of the limitations.  Don't expect to see a friend drive by in the opposite lane on the interstate, and then try to page them for a conversation of any length.
    Also, be aware that the cheaper the setup, the more likely you're going to run into problems with interference (RFI,EMI, ignition noise, whatever you want to call it.)
    At this level of spending, I would advise you to worry more about your antenna than your radio.  The best radio in the world wont make up for a rotten antenna.
 

Spending Too Much

    The other extreme to spending too little is spending too much.  This is what a lot of people do.  Like getting talked into buying a $2000 kevlar kayak when a $300 canoe would suit someone just fine.  Not everyone needs DSP noise elimination, or the ability to transmit single sideband, or other fancy options.  Some people, whether they want to believe it or not, only really use their CB's for a total of a couple hours a month, and never really get to use all the fancy features to their full potential.  Just like some people buy a $300 stereo, and others spend $3000, you may be quite happy spending no more than $50-$70 total on your CB and antenna.
    You might be considering certain specialty features, like one that has the weather bands built in, or is weather resistant, or a remote mount CB that puts all the controls on the mike, and hides the radio itself under the dash.  These kind of options are going to drive up the price of the radio, but if you want one of these, go ahead, knock yourself out, 'cause these options aren't dependent on someone saying "oh, this is worth it!  You'll get MUCH better reception if you buy this one that's $80 more."
    In the world of under $100 spending, I can't see going into long arguements on how X brand radio has  better selectivity and sensitivity than Y brand, or is better at eliminating noise.  If you really think you need some of the fancy features, or think you might be concerned about the relative performance of one radio over another, go read the more in depth areas of this site, and find out if it's really neccessary.

Installation

So, you've bought a Kmart blue light special, and now you want to know how to go about installing it. Well, I can't really help you when it comes to where to put the radio.  Basically, wherever it's convenient to reach the controls, and not in the way of your legs, or head.  I mention your head, because many people like to mount the CB on the roof, somewhere around the rear view mirror or sun visors.  Think twice before doing this.  Admittedly, this is a convenient spot, but a friend of mine who's a volunteer firefighter pointed out the extreme danger of mounting a large, heavy object with sharp edges in the general path that of your skull will take during a collision.  If you're short, and drive a full-size pickup, this is obviously not as much of a consideration as if, like me, you're 6'2" and driving a (relatively) compact Jeep Cherokee XJ.  In this case, I'd be mounting the beast right in my face.  Not very smart.
    Check to see how the channel display on your radio looks in direct sunlight.  Some aren't very readable, and you may want to find a spot that is relatively shaded to make it more readable.  The biggest suggestion I could make is try something temporarily, by securing the radio with duct tape in a place you might like for a few days before cutting up your dash.
    Wiring the power to the radio is pretty straightforward, especially if you've ever added anything electrical to your vehicle before.  Most radios have a ground wire (duh..) and two power leads.  One hooks to an unswitched battery circuit, and the other to your accessory circuit.  The first provides power at all times for electronic tuning to remember your channel selection when you pull out the keys, and the other powers the radio when you turn the ignition on.  Some only have one wire - especially the older non electronically tuned radios.  These get hooked up to just the accessory circuit.  A convenient way to hook up a radio is to buy the little spade fuse adapters sold at Radio Shack, the kind that slip over one blade of a fuse, and then get inserted into the fuse block.  They work great.  Just make sure you put the adapter on the downstream side of the fuse.  Alternately,  just buy an adapter and plug it into the cigarette lighter.   That's the best solution if you plan on using the radio in more than one car.
    Now we're up to the coax cable and the antenna.  This is where things get interesting, and where lots of arguments start.  I'll save all the technical talk for the Radio 101 theory pages for those who wish to know all the geeky stuff.  If you really don't care about getting the best performance out of what you just bought, skip this stuff, and mount the antenna wherever you darn well please, with as much coax run around the truck as you can.  You'll still be able to talk car to car, but not much else.  Otherwise, keep reading.
    First, try to keep the amount of coax cable between your radio and the antenna as short as possible.  There is a certain amount of loss in any cable, and the longer the run, the more of your signal is lost before it even reaches the antenna.  If you don't feel comfortable cutting the wire that came on your antenna, don't bother.  It may void any warranty.  But on the other hand, don't go crazy adding extension patches to your antenna so you can mount it 30 feet away from your radio.  Keep the path as short as possible.  I'll be writing more on this.
    Where does the antenna go? Ideally, on the highest point of your vehicle, and even more ideally, permanently (this means drilling holes) mounted in the middle of a large horizontal piece of sheet metal - your roof.  Any other installation is a compromise from this ideal, but sometimes awkward, location.  The roof acts as a ground plane, a sort of sounding board, that focuses the energy coming off the antenna in a direction where it does the most good - straight out sideways.  Most antennas are designed to depend on a ground plane for good operation.
    So why do truckers - folks who are supposed to be so concerned with good CB installations - mount their antennas on their mirrors rather than the roof of the truck?  Simple - height restrictions.  They'd benefit just like anyone else from a roof mount, but then they'd hit every bridge,  traffic light, and power line on the road.  They usually mount two antennas, one on each mirror, because from any given angle other than straight ahead or behind the truck, one of the antennas is blocked by the bulk of their truck.
    If you're concerned about whacking the antenna on low branches, drivethru overhangs, or parking garages, that's a very valid concern on tall vehicles.  The most expensive, highest mounted antenna in the world is useless if it's broken.  There's other options.  Some antennas, such as the American Antenna K40 that I bought, have a bayonet quick disconnect that will let you yank the antenna off the roof and stow it for safekeeping.  The only problem with this is remembering to take it off before it's too late - a big issue if you drive a tall vehicle and drive into parking garages often.  Also you lose the ability to transmit (Well, you can, but it wont be pretty...)  I'm contemplating making a spring loaded base for my antenna to keep it from breaking if I forget to take it off,  or just don't feel like it.

    Okay - you say you don't want that big ugly antenna in the middle of the roof.  Other choices, in my order of preference, would be the gutter or light bar,  the trunk or hood, the rear of the bed rail of a pickup, the mirrors, or a bracket halfway up the side of the body (similar to the way Army vehicles mount them on the side)  Just remember, altitude is everything.  As an extreme example, CBers have reported that my signal as being "5 by 9" from 50 miles away when I transmitted with a 1 1/2 watt walkie talkie from the top of a mountain.  Altitude is everything, and having a good ground plane is a close second.
    About the worst place you can mount an antenna is on your back bumper.  The only worse place is under your vehicle.  Just like with the truckers mentioned above, nearly half of the circle around the antenna is blocked by a large chunk of sheet metal called a tailgate.  On cars, pickups, and jeep CJ/YJ/TJ's this is slightly less of a problem than sport utilities and minivans, since the rear of the vehicle isn't as tall.  It's still not a good use of an antenna.  If you really want to mount one on the bumper, mount one up front, too.  That way, you'll have two antennas, just like the big dogs.

So, once again, I say antenna placement is vital - put it in the middle of the rooftop if you possibly can! (Just don't do what I did, and end up nearly drilling the hole to permanently mount it right through my dome light and wiring - check for that before drilling...)
 

Antenna Tuning

    Great - you're still with me.  This area might be a bit confusing, but it's still something you should know about.
    Whenever you talk about CB radio for any length of time, the term "SWR" will come up.  SWR refers to Standing Wave Ratio.   It's the ratio of standing waves (duh).  The two standing waves in the equation are your transmitted wave (or foward, or output, or whatever you want to call it) and your reflected wave.  Just like you have to tune a hi-fi speaker cabinet for best sound, you have to tune an antenna - find its sweet spot, in other words.  Just for reference, if an SWR reading is 1 to 1, that's perfect, and also practically impossible to achieve.  You're going to get SOME reflection no matter how good your equipment is.  Maybe your meter just can't measure that low.   A signal of 1.1 to 1 is great.  If your reading climbs to 1.5, that's okay if you're not too concerned with the best signal.  Above that, and you're doing lousy.  Things that can affect the SWR of the antenna are mounting position of the antenna, parking the vehicle right next to a building or other vehicle, open doors on the truck, etc.  Some affect it more than others.  Try to eliminate the obvious stuff before playing with the antenna.
    Without getting too deep into antenna theory (read the other areas if you want that), I'll describe whats goin on.  The frequency that a radio (any radio, not just CB) transmits and receives on can also be referred to as a wavelength (the length of the radio wave).  An antenna has to be adjusted in its length to closely match the wavelength of the transmitted signal.  If an antenna is perfectly tuned, all the RF energy being transmitted by the radio will be effectively radiated by the antenna.  If the antenna is out of tune, some of the energy is actually reflected back to the radio, and is not transmitted.  Too much energy reflected back to the radio not only seriously hurts the effective power output of your setup, but it can actually damage the radio over time.
    The way you tune an antenna is to use a meter that measures the SWR, and adjust the antenna until you get the lowest possible SWR reading you can.  Technically, you are only worried about eliminating or minimizing the reflected power.  The ratio of output to reflected power is kind of a moot point.  Maybe you're using a meter that can measure reflected power separately.  This is fine.  Wherever I mention looking for a smaller SWR reading, substitute smaller reflected reading, and press on.
    I mentioned earlier that maybe the store where you bought the radio will tune it for you, or maybe they'll loan you the meter so you can tune it yourself.  If you are going to set up and forget about your radio, this is great.  If you see a point in your future where you're going to play with your CB setup, it's a good idea to get at least a cheap SWR meter, or make friends with someone who owns one.  Contrary to popular belief, you don't have to spend $80 on a meter if you only spent $50 on the radio and antenna.  I picked up my first one for about $15 new, and years later measured its accuracy against a $1100 meter (Bird digital model 4391M), and the readings were close enough for the average CBer.  If you want to spend lots on your meter, wait until you have a CB that's worthy of the better meter.  If you buy your own, you could maybe leave it permanently installed, and then you get another useless gauge in your truck to look at.
    Okay - how do you tune your antenna with the meter?  First, hook it up to the back of the radio, then hook your antenna up to the meter.  Then, read the instructions that came with the meter on how to calibrate the meter, and how to set it to read SWR.  You got instructions with the meter, didn't you?  :-)

    Tune your radio to a middle channel, like 19 or 20.  Press transmit, and look at the meter.  With any luck, your reading is 1.2 or less, and you can call it a day (remember, this is the section of the website that isn't dealing with getting really uptight over the smallest details...).  If it's more, or you are obsessed with perfection, keep going.  It is entirely possible that with the equipment you have, and the place you mounted your antenna, that you will not be able to get your SWR reading below 1.5 to 1.  If so, you'll have to re-examine what exactly you've done, and how you set up your equipment, and probably read more than just this quick-start guide to get the most you can out of your setup.

    What you do now is tune the radio to the last channel (40, unless you have an ancient radio), and press transmit.  Make a note of the reading.  Then tune to channel 1, and do the same.
    If the SWR measured on channel 40 is greater than the SWR on channel 1, that means that your antenna is too long.  Why, you ask?  Because, I answer, the wavelength of channel 1 is longer than that for channel 40, and the meter said your radio was happier transmitting on the longer wavelength.
    If the reading was greater on channel 1 than channel 40, it's just the opposite.  You'll need to shorten the antenna.
    To lengthen or shorten the antenna, most antennas have a small allen screw on the base that you loosen to move the antenna whip up or down.  Move the whip in the direction required just a little bit (maybe 1/8" to start), and try all this over again.  Keep doing it until the readings for both channel 1 and 40 are almost identical.
    Now, tune back to channel 19 or 20.  You should see a very good reading, lower than what you could get on either end channel.  What you did is tune the antenna so it's happiest transmitting in the exact middle of its range.  You could set it up to have the lowest reading on, say channel 35, if you use it a lot, but then you're going to get higher SWR readings on the lowest channels.  It's all a compromise.  For the record, my CB and antenna combination gave me an SWR of less than 1.1 to 1 on channel 19, and I could regularly get contacts in hilly Vermont of more than 10 miles, although 7-10 miles were more the norm. For practical, extended conversations while driving through the hills, 5-7 miles was normal. All this without lots of expense or illegal equipment.  Basically, if my radio could hear a signal reliably, I could talk to the person.  You can't ask for any more.

    There - now you're done.  Go out and enjoy the CB.  And on your way out, be sure to check out the section on radio discipline & manners, because we're all trying to live, work, and play on the same section of radio space, and we need to respect others using this very public resource.  Think of it as "Treading Lightly" on the CB wilderness.
 
 Last update: 25 August 1998


 Last update: 25 August 1998
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