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How to Calibrate a CB Radio – 6 Easy Steps to Follow

Writen by Edwin Jones

Fact checked by Andrew Wright

how to calibrate a CB radio

You have installed your CB radio into the dashboard, and your antenna is mounted in a suitable position. Everything is connected, and you think your radio is ready to work, right? Unfortunately, you may get unsatisfactory results. Hence, it is essential to calibrate CB antenna before using the CB radio.

This article will discuss how to calibrate a CB radio to ensure the best possible signal. To do this, you need to start with preparing an SWR meter.

6 Steps to Calibrate a CB Radio


Step 1: Find a suitable place to park your vehicle

Let’s start by finding a suitable area to park. It is a good idea to choose a place with no obstructions, such as buildings or trees, within 12 to 15 meters of your antenna. Even your friends should not be moving around the car. In addition, make sure you are inside the car with closed doors and windows.

Step 2: Buy an SWR meter

Before buying an SWR meter, it is wise to check if your CB radio comes with this meter. In fact, some of the ones we’ve reviewed have a built-in SWR meter.

After purchasing an SWR meter, read the manual from the manufacturer to see what you can do with your SWR meter.

Step 3: Connect the SWR Meter into your radio set-up

It is time to connect the SWR meter to the CB and the antenna. Connect the end of the antenna cable to the input on the SWR meter first. Then connect the cable that comes from the SWR meter to the antenna input on the back of the radio.

Step 4: Calibrate your CB radio

  • Find the switch on the SWR meter and set it to “FWD.”
  • Turn the CB radio to channel 1.
  • Press and hold the button of the microphone.
  • Find the knob on the SWR meter labeled “ADJUST” or “SET” and rotate it until the needle touches the setting position at the end of the range.
  • Turn the switch on the SWR meter to “SWR” or “REF” while keying your microphone.
  • Record the reading the SWR meter gives you and release the transmit key on the microphone.

Next, it is essential to repeat this process for channel 40. In most cases, the reading on channel 40 will be slightly different from the reading you get on channel 1, especially if your antenna has not been tuned before.

Step 5: Analyzing the readings

As mentioned above, the amount of mismatch between these readings should be as close to zero as possible. In other words, you need to adjust so that these two readings are as close to each other as possible. Of course, this is unlikely to happen if you have not tuned your antenna before.

At this step, it is essential to assess which channel’s reading is higher. Channel 1 or channel 40? How you tune your antenna will depend on this result.

Step 6: Tuning the antenna

The antenna is too long if the SWR on channel 40 is higher than that on channel 1. Hence, you need to shorten the antenna. Most antennas allow you to shrink or stretch them a bit. If that is not feasible, it is time to buy a new antenna.

If the SWR on channel 1 is higher, the antenna is too short, so your antenna needs to be stretched.

For dual antennas, if these readings are less than 2.0, your CB radio is safe to operate even though the transmission may not be optimal. However, if these readings are higher than 3.0 or in the red area on the SWR meter, you will need to remedy them before using the radio.

Tip: Many people agree that it is easier to get good SWR readings when the antenna is located on the car’s roof.

What is the SWR Meter


If you have a CB radio, it is essential to invest in an SWR meter. It is the only device that helps you to calibrate your CB radio to get absolutely perfect sounds.

People use SWR meters to measure something called “standing wave ratio.” That’s why the device is called an SWR meter. Simply put, this tool helps you determine the level of signal mismatch between the transmitter and the antenna.

Sounds complicated, doesn’t it? In general, you should make an effort to bring the amount of mismatch between the two to as close to zero as possible. Of course, it never seems to reach zero. By following the instructions above, you can get a mismatch between the two pretty close to zero.

How Often Should We Use the SWR Meter

In most cases, antenna tuning usually takes place every few months. If you find the sound quality degraded, the cause may be that the antenna has been deflected a bit. Therefore, you may want to do a quick check with an SWR meter to reposition it.

If you have to move to a new area, it is best to consider recalibrating the antenna. This adjustment is not strictly necessary, but making sure your antenna is in the best position is a good idea.

If you want to know more about how to calibrate a Cobra CB radio, please watch this video on cobra 29 LX SWR calibration.

Frequently Asked Questions

What are SWR Meters used for?

SWR Meters are commonly used during antenna installation and tuning. In addition, they are also being used in microwave-based medical applications.

What causes the SWR meter to register danger on all channels?

  • A short in the coaxial connectors
  • Poor grounds
  • An improperly installed mounting stud

What is the best height for a CB antenna?

The higher the antenna is from the ground, the better it will perform. Therefore, you should install the antenna vertically 5 to 10 feet above the roofline and away from power lines and obstructions.

Where is the best place to mount a CB antenna?

The best location for a standard antenna is the center of the roof, where you will have the most excellent ground coverage.

Does a CB radio need an antenna?

Without a CB antenna, your radio is useless! In most cases, CB radios come with a microphone, a stand, and a power cord.

Are all CB radios the same?

The fact of the matter is that all CB radios, regardless of price or size, have the same transmission power out of the box.

Is Adjusting CB antenna necessary?

It is not a must! However, calibrating CB antenna is recommended if you are not satisfied with the sound quality of your radio.


After reading our article, you surely know how to calibrate a CB radio. In general, you can complete this process in a few minutes. CB radio calibration is not a must; however, this will ensure that you always have the best sound quality.

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