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How to Lower SWR on Antenna? (A Step-by-step Guide)

Writen by Edwin Jones

Fact checked by Andrew Wright

how to lower swr on antenna

Are you clueless about how to lower SWR on antenna? You came to the right place. This guide will let you know the steps and provide valuable tips.

Make the most of your radio and antenna by fixing its SWR. It not only optimizes performance but also prevents damage. Read on and learn how you can lower SWR on CB antenna.

A Step-by-step Guide to Lower SWR on Antenna

1. What to Prepare

  • SWR Meter
  • Vise
  • Bolt cutter
  • Stud
  • Metal sheet
  • Coax cable

Now that you have prepared the necessary materials, it’s time to start working. Follow the simple steps below to optimize your antenna’s performance in no time.

These steps are divided into two parts. First, you must confirm CB radio SWR too high. After conducting the test, you’ll now find ways to lower SWR on vertical antenna.

2. Pick an Open Space

Your best bet is an open space. If possible, there should be no physical obstructions around the area, such as buildings, trees, electrical posts, and similar structures.

I would do it in an open field. However, I understand that many of you may not have access to such a space. So, choose one that is as unobstructed as possible.

The reason why you need an open space is that antennas are sensitive. Nearby objects can distort signals. In turn, it can make the SWR readings inaccurate.

3. Connect the SWR Meter


Before anything else, you’ll need to disconnect the radio and the antenna. The two are often connected by a coaxial cable, which you’ll need to unscrew from the back of the radio.

Attach the end of the coaxial cable that previously connected the antenna to your SWR meter. Look for ANT or Antenna to know the right place to attach the cable.

Next, work on another cable to connect the SWR meter to the radio. In most cases, the transmitter port is labeled so that you won’t be confused.

4. Turn the SWR Meter On

With the connectors now in place, it’s time to power on the meter. In newer models, you’ll find the power button in front. Some models will have it on the side.

Nonetheless, you can also find models without a power button. Such is especially the case in old analog models. It will automatically turn on upon connecting the radio and antenna.

You will often find a Function button if there is no power button. 

5. Calibrate the SWR Meter


This is an important step when you’re using an analog meter. It comes with a calibration dial, which you’ll need to rotate clockwise. Keep on doing so until the needle is stationary.

6. Tune in to Channel 1

Go to the lowest frequency on your CB radio, which is Channel 1. While doing this, the switch in the meter should be in the Forward position.

While still in Channel 1, hold the mic’s transmit button. This is important as it activates the transmitter, and in turn, it sends the signal the meter has to evaluate.

Watch over the needle on the face of the SWR meter. Once it reaches Set, flip the Ref switch in the meter and record the number shown in the display.

Related: 5 Steps On To Tune A CB Antenna Without An SWR Meter

7. Tune in to Channel 40

This time, you’ll need to work on the highest channel in your CB radio, Channel 40. The process is the same as what I talked about above.

8. Evaluate the Reading

You’ll know whether it’s high or low with the readings you previously noted. Any reading above 2 is a red flag.

To fix high SWR on CB, follow the steps in the next section.

9. Shorten the Antenna

Reducing the antenna’s length is one of the most common solutions to minimize high SWR on 1 and 40.

To make the antenna shorter, start by putting it in a stable position. I suggest you secure it in a vise to work properly.

Next, cut the antenna by .5cm. A bolt cutter can be a handy tool for this job. Don’t cut more than such a length at this point.

Once done, return the antenna to its base. Secure the antenna in its original position and check the SWR. If it’s still not low, repeat the cutting. Again, don’t cut too much.

In some models, making the antenna shorter is easier. It can come with a tunable tip, reducing the length without needing to cut.

When you have SWR higher on 40 than Channel 1, you have a long antenna. Making it shorter will do the trick.

You’re also probably curious about how high SWR shorten or lengthen antennas. If it’s higher on Channel 40 than 1, shorten it. Meanwhile, make it longer if it’s higher on Channel 1.

10. Correct the Placement of the Antenna

An antenna’s position is crucial for its optimal performance. Hence, if you want to lower SWR on ham radio antenna, you might need to reposition it.

In most cases, positioning it next to the cab can make the SWR high. The same thing can happen when it’s next to metallic objects.

11. Ensure Proper Grounding


Grounding the antenna properly to the chassis is vital for getting low SWR readings. Fixing it is an easy solution.

In case you don’t know, the ground plane is the metal part under the antenna. It must be a good conductor to ensure antenna performance.

One thing that you can do is run a thick wire along the chassis. To be effective, you must use a wire with a rating of at least ten amps. Putting a metal plate under the antenna base can also help.

12. Fix the Coaxial Cable

Another part that you should not miss is the coaxial cable. It connects the antenna and the radio, making it crucial in the SWR reading.

In many instances, the coaxial cable can end up coiling. It’s especially the case when it’s too long. When such happens, signal feedback is possible.

So, the best thing to do is to check the coaxial cable and straighten it when there are coils. It should not have any damage.

13. Tighten the Stud Washer

While it might seem small, the stud washer is vital in the antenna’s SWR. A short can happen, but using a nylon washer can prevent this situation.

Using a stud is vital because it separates the antenna and the ground. Hence, when the two parts touch, there can be a problem.

Testing such, however, isn’t a simple guessing game. To make things easier, you’ll need a multimeter, which will let you assess continuity.

What Causes a High SWR?

Different factors can contribute to a high SWR reading, including the following:

  • Conductivity between the cable and external components of the antenna
  • Wrong positioning of the antenna
  • Dirt buildup that could short parts of the antenna
  • Incorrect connection between the radio and antenna
  • Defective coax
  • Lack of proper ground plane

Tips to Choose an SWR Meter

If you need to lower SWR on dipole antenna or any other type of antenna, an SWR meter is essential. However, they’re not all the same. Here are some tips for choosing the right one:

  • Digital or Analogue: Both are accurate. However, a benefit of a digital SWR meter is that it’s easier to read.
  • Power Rating: SWR meters are built to handle different power ratings. Most models are good for up to 100 watts, while higher-end alternatives can measure up to 500 watts. Others are more versatile, offering a selectable power setting.
  • Frequency Range: If you need an SWR meter for your CB radio, find one with a range of 26 to 27 MHz. Meanwhile, for higher frequencies, you’ll need a more capable one.
  • Needle Type: One option is a cross-needle display, which most users prefer. You can also find models with a single needle.
  • Display: A good SWR meter has a visible display, making it easy to use. Look for one that comes with a backlight.
  • Accuracy: Consider how accurate the SWR meter is. The best way to do this is to read reviews and learn from the real-life experiences of other people.

What Happens If SWR Is Too High?

A high SWR damages a radio. Hence, going above the recommended range can be a disaster. However, note that it happens only when you’re transmitting and not receiving.

The damage that the high SWR can cause is often a result of high voltage.

Aside from damaging the radio, performance issues are also common. Audio distortion is possible. It is crucial that you stop transmitting when the SWR reading is too high.


Now that you reached the end of this guide, I hope that you learned a thing or two about how to lower SWR on antenna.

As noted above, the process starts by measuring the actual SWR. This way, you can confirm if it’s indeed high.

Once you confirm, you can adjust SWR on antenna by making it shorter, changing the ground plane, fixing the coax cable, and changing its position, among other things.

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