How To Tune A CB Radio

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Updated June 27, 2022

So you bought the best CB radio and have installed it and the antenna. What now? Can you just start talking to your contacts? Actually, there’s one thing you have to do first. You need to tune the CB antenna. This is also called setting SWR on your CB radio. I’m going to walk you through the process of how to tune a CB radio to improve your radio’s performance.

How To Tune A CB Radio. But First, Why?

You may think that tuning the radio and antenna is not important, but it is actually the most important part of setting your CB up if you want it to perform at its best. You have to remember that CB radios have only 4 watts of power, which means that you’ll need to get your antenna system as perfect as possible to have optimal radio transmission and reception. It will give you less interference and there will be fewer dropped signals. An untuned antenna can even damage your radio. This technique works for base stations or mobile units and has to do with the length of the antenna. It also applies to ham radios.

Tuning Your CB Radio

The equipment you will need is a short coax cable (or jumper lead) and an SWR meter. So let’s walk you through the process of getting a fine tuned CB. If only your car was the one from Knight Rider and the car could do it by itself.

First, park your vehicle in an area with no obstructions within 10 to 15 meters of your antenna, Make sure there are no trees or buildings around you to impede your radio power. You should be inside the car with the doors and windows closed. This will help give you an accurate reading.

Connect The SWR Meter

Now connect the SWR meter. Start by disconnecting the coaxial cable from the back of the radio and reconnect the end of the cable that is going to the antenna, to the SWR meter. Now use the jumper lead to connect your radio to your SWR meter.

Now you are ready to measure the SWR. One thing to remember is that you should have the microphone the same distance from the meter for every test you perform to get accurate readings.

Next, you will switch the SWR meter to FWD position and go channel 1 on the radio. Press and hold the talk button on the microphone while turning the SET or ADJUST knob on the SWR meter until the needle hits the setting position at the end of the range. Then turn the switch on the SWR meter to the REF or SWR. Write down the SWR meter reading on the channel.

After that, you will have to repeat this procedure for channel 40. The idea is that you want both readings to be as close as they can be. You want to get it to at least a 1.5:1 ratio or below for a decent signal from a properly tuned radio.

Adjusting Your CB Radio Antenna system

Your CB antenna is too long if the SWR level readings on channel 40 is higher than your reading for channel 1. You’ll have to adjust the length. However, your antenna is too short if the SWR on channel 1 is higher than your reading for channel 40. It has to be the proper physical length and readings on both channels help you to find the sweet spot.

There are CB accessories that can make it easier. Some antennas have an adjustable tip that uses a tuning screw to adjust and hold it in place. Otherwise, if your antenna is too long, you’ll need to cut it, shortening the antenna down to the proper length. Cut a very small amount off and then take your reads again. If it is too short, you have to get more length. These days most antennas have a way to add length, so consult your manual for the best way to attain tuned antennas.

It takes just a bit of work, but it is easy now that you know how to tune a CB radio for proper radio operation. Read about some of our other car accessory reviews.

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