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What is SWR on a CB Radio? – Standing Wave Ratio Explained

Writen by Edwin Jones

Fact checked by Andrew Wright

What is SWR on a CB Radio

After successfully installing your CB radio, the next step is measuring the efficiency of your antenna with the use of an SWR meter which stands for Standing Wave Ratio. SWR meter ensures that your CB radio is transmitting correctly.

In this article, we will define what is SWR on a CB Radio, why it matters, and how to interpret the readings. Understanding and maintaining the SWR on your CB radio will surely optimize your CB radio experience.

Below is a quick sum-up of what different SWR readings mean to your radio performance: 

SWR Range Description Risk of Damage Immediate Action? Action to be Done
1.0-1.5 Ideal Reading No risk of radio damage No Strive range closer to 1.0
1.5-1.9 Efficient Reading No immediate radio damage No Tune the antenna for a better signal
2.0-2.4 Satisfactory Reading No immediate radio damage No Mont antenna higher
2.5-2.9 Performance Degradation Potential Risk of Damage if Continued Use Yes Adjust or replace the antenna
3.0 + Poor/Critical Performance High Risk of Significant Damage Yes Rectify grounding issues or antenna stud

What does SWR mean on a CB radio?


SWR stands for Standing Wave Ratio. It is a tool that measures how well the CB radio antenna is working. CB SWR meters are used between your radio and its antenna to check if there is poor or bad ground.

An SWR calibration can measure the ratio of how much output power finds the destination then reflected back.

This device is attached between your CB radio and antenna. There are also SWR CB radios that come with a built-in meter. The reading should be suitably low to avoid any damage to your radio. 

Why is SWR important to your CB Radio?

An SWR meter is important to operating your CB Radio for the following reasons:

1. It Helps Measure Signal Transmission


When the signal of your radio is not transmitted properly, this will cause poor performance and can potentially cause damage to your radio. An SWR meter can help you determine the ratio of your RF current at a loop.

Having a high SWR means that there are extreme voltages and currents on a loop. The lower the SWR ratio reading, the better your radio is performing, as radio frequency power does not get sent back much to the transmitter.

2. Maintains Radio Safety and Performance


When your SWR meter reading is between 2.5-2.9, this indicates that there is a problem with your transmission. Checking your antenna or adjusting its mount might be the simple solution.

Having a 3.0 reading, on the other hand, means that the antenna problem is significant, and you have to fix it right away or it could cause severe malfunctions to your radio system.

The SWR meter will help you keep track of the effectiveness of your radio transmission wherever you may be.

SWR Reading Range and Explanation

1. SWR 1.0-1.5


If your SWR meter falls between 1.0 and 1.5, then you are in an ideal range– this means that your signal transmission is efficient and your radio is well-tuned. Although if you’re at 1.5, a little tuning on your antenna may help you drop to 1.0.

The difference between 1.0 and 1.5 is not very noticeable, but getting the SWR to 1.0 can help your CB radio perform better and last longer.

2. SWR 1.5-1.9


At this range, your radio is at adequate performance. However, there are many factors that can hinder your SWR to a lower range such as mounting constraints to your antenna. Communication and radio performance are still acceptable at this stage.

3. SWR 2.0 -2.4


SWR range 2.0-2.4 is not ideal. Immediate damage to your radio is not very likely but this range usually means that your antenna is not adequately mounted. You can try troubleshooting actions like mounting your antenna higher or choosing a more suitable vehicle to mount your CB radio.

4. SWR 2.5-2.9


When you have a 2.5-2.9 SWR reading, there is a sign of performance degradation to your signal which can potentially lead to equipment damage. You may experience distorted signals and reduced clarity when communicating at this SWR range.

Try inspecting your antenna and mounting it or buying a new one if the issue persists.

5. SWR 30+


When your SWR reading is at 3.0 or above, your signal will be severely compromised, and significant radio concerns happen if you continue using your radio at this range.

Surpassing the 3.0 Threshold will impact the quality of communication and further damage your radio significantly. It is important to avoid transmitting with your CB radio at this SWR range.

Measuring SWR on CB Radio

Use your SWR meter using these simple steps:

1. Connect your radio’s coaxial cable to the transmitter port on your SWR meter. Then, connect your antenna’s cable to the antenna port of your meter.


2. Switch your meter to “FWD”


3. Tune in to radio channel 1

4. Press your microphone button and hold


5. Turn the SWR meter knob to “REF” or set  “SWR” on the CB radio


The SWR meter will then display the range of your CB radio channel. If the SWR is higher on channel 40 than on channel 1, you might want to shorten your antenna. If it’s vice versa, you should lengthen your antenna.

You can try to adjust the length of your antenna based on the channels you’re tuning in. However, if your meter reads high ratios, you should fix your antenna right away to avoid low-quality communication and radio damage.

Tuning methods for optimal SWR

There are many factors that may affect your CB radio’s high SWR meter. Here are the following issues and basic SWR adjustments you can do.

1. Tuning a CB antenna – There could be antenna issues with your SWR radio, meaning, your antenna is either not mounted correctly or its length needs to be adjusted.

Make small adjustments to your antenna and continue until you reach the desirable range. This will help you know what antenna adjustment gives the best reading.Tuning-a-CB-antenna

2. Use a multi-test meter- Check the coax cable and antenna stud. There could be short circuits that would interrupt your SWR reading. There may also be broken electrical ground that can disrupt the SWR meter’s result.Use-a-multi-test-meter

3. Finding good location- If your antenna is mounted close to the vehicle’s body, this may result in high SWR reading. Try mounting your CB antenna on a flat radiating surface. It should be placed on a metal surface.


Now, you know the answer to “what is SWR on a CB radio?” Being A CB radio enthusiast requires mastery of the Standing Wave Ratio (SWR) for both your CB’s performance and safety.

With an SWR meter, you can make sure that your radio is transmitting effectively without getting damaged. An ideal SWR range is between 1.0-1.5.

It is important to remember that reaching ranges 3.0 and beyond needs immediate intervention. Operating at this range is not advisable. Take corrective action such as antenna adjustment, and addressing grounding issues.

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