How does a CB radio antenna work?


Simply put, tuning your antenna is the most critical step in ensuring that your CB radio system performs at its best after installation. Since CB radios only have 4 watts of power, you’ll need to make your antenna system as effective as possible in order to get the most out of your radio’s transmission and reception. Poorly tuned antennas can cause increased interference, dropped signals, a lack of ability to make high-quality contacts (which is, after all, the point of having one mounted on your rig), and even destroy your radio!

Continue reading if you’re persuaded of the need and usefulness of this crucial move.

Is there a distinction between tuning my CB radio and tuning my CB antenna on my CB radio?

Without a doubt. The tuning of a CB radio differs from the tuning of a CB antenna. CB radios can be tuned to improve efficiency as well. For example, for new CB radios purchased from us, we provide our Peak and Tune Service. We’ll put the new radio to the test and change the power and modulation to make it sound as good as possible. It’s a common misconception that you’re tuning the antenna to the radio when you do this. Tuning a CB radio involves tuning the radio itself, rather than the antenna. The antenna is tuned to the vehicle or application, not to the radio, when tuning a CB antenna.

What does it mean to tune a CB antenna?

You’re fine-tuning the antenna for your particular vehicle or programme. Tuning a radio device entails adjusting an antenna to the proper height so that the radio can send out as many signals as possible. This varies depending on the vehicle/application, the position where the antenna is mounted, the ground plane (or lack thereof), and other factors.

With an SWR metre, you first determine how well the device is doing now, and then change the antenna length or position to boost the signal.

If your radio has a built-in SWR metre, you can simply tuning the antenna using the radio—consult your owner’s manual for instructions. When in doubt, get in touch with us! We are delighted to assist you. If your radio doesn’t have a built-in SWR metre, you’ll need to use an external SWR metre like the AUSWR to connect the radio to the antenna.

When it comes to CB antenna tuning, the aim is to achieve the lowest possible SWR. You do this by raising or decreasing the length of the antenna in very tiny increments of about 1/4 inch or less (depending on the SWR metre readings), then retesting. This will offer you the best transmission performance and reliability. You may have a great radio, but if your antenna isn’t tuned properly, it’ll be like getting a boat anchor in your car (to use CB slang).

Tuning your antenna is critical to your system’s overall efficiency.

What exactly is SWR?

Standing wave ratio is referred to as “SWR.” A “SWR” metre is used to determine how well a transceiver’s (radio’s) transmit power signal travels through the antenna system and into the atmosphere. Checking and setting the antenna is vital to the transceiver’s overall efficiency (radio). The SWR must be tested during the installation of a Business Band, CB, Ham, or Marine radio or when installing a new antenna to ensure that the transmit power from the radio is travelling through the antenna system correctly. An antenna system with poor performance reduces (transmit and receive) range and can harm the transceiver (radio). The transmit power is reflected back into the transceiver when the signal does not pass through the antenna system correctly, resulting in decreased range and the risk of damage to the internal parts of your radio.

We suggest that you review your SWR on a regular basis and if the antenna system is modified or potentially damaged.

SWR (Signal to Noise Ratio) Meter

The test is performed using a “SWR” (standing wave) metre and a short coax cable (jumper cable with two PL259 ends) between the radio and antenna system. A high reading on the “SWR” metre means that there is an issue with your radio or antenna system’s installation. When you run the “SWR” test, the metre will tell you if your antenna is working properly and give you a reading so you can change it for optimal efficiency. SWR readings will reveal whether the (radio/antenna) ground is weak or bad, if the antenna is poorly set, whether the antenna is in the wrong place, or whether there is a coax obstruction or low. A low test reading on the “SWR” metre (in the red) suggests a serious issue with the antenna system (possibly the wrong type of antenna system for your application) or a bad ground that needs to be corrected or adjusted before using the radio. DO NOT TURN ON THE RADIO UNLESS A GOOD “SWR” CAN BE OBTAINED.

What are the options for adjusting the antenna length?

Some antennas, such as the Firestik FS II Series with the tuning edge, the Wilson W4FD-B, ProComm’s JBC Series with tuning rings, and others, provide fast tuning choices.

Some antennas are more difficult to tune and may require you to trim the steel whip or the antenna’s wires.

The manufacturer of your antenna should include guidance on how to adjust it. As previously mentioned, some CB antennas, such as the Firestik, have a tuning tip, which is a tiny screw at the top of the antenna. You can easily lengthen or shorten the antenna by turning the screw in or out on that sort of antenna.

What you’ll need and how to get started tuning a CB antenna

Everything you need to tune a CB antenna is your mounted radio, coax, antenna, and an SWR metre. Begin by choosing a suitable tuning location (a car parked in an open area), then attach the SWR metre. Then, using the step-by-step instructions that follow, you’ll be able to start actually tuning the antenna.

Choosing a site for SWR research

While tuning your best cb antenna, park your vehicle in a large open field. When you tune your antenna while your vehicle is close to other cars, houses, or even people, you can get an inaccurate reading. Also, make sure your doors, hood, and windows are closed each time you take a reading. Make sure the plastic cap on the tip of your antenna is in place each time you take a reading.

What is the best way to attach an external SWR metre?

Some CB radios, such as the Cobra 29 Classic, have a built-in metre. Step-by-step instructions for using the built-in metre will be included in the owner’s manual. If your CB radio doesn’t have an SWR metre built in, you’ll need to purchase one. The famous AUSWR SWR metre is inexpensive and includes a coax jumper cable for connecting the metre to your CB radio.

If your CB radio does not have a built-in metre, the AUSWR SWR Meter is a common option.

There are other SWR metres available, some of which have additional metres. A standard CB radio installation would resemble the illustration above. The installation in the image below has an SWR metre added in line. Connecting an external SWR metre and tuning a CB antenna are detailed in the instructions further down in this article. For more information, visit: