What Is A Balun? Why Do You Need One & When To Use It

What Is A Balun? Why Do You Need One & When To Use It

A balun uses voltage currents to create balanced lines from your antenna system to your cable system. Maybe you’re looking to install antenna equipment yourself, or you want to know how the professionals do it. If you’re interested in learning how the antenna, electric, and other structures work, check our article.  

We’ll provide definitions of technical language along the way so that everyone can follow along without feeling confused or disoriented. With the guide, you’ll gain a full understanding of all things balun and antenna without the struggle. 

The specific focus of this article will be baluns, which are essential parts of antenna voltage systems. You’ll learn about how they work, the two different kinds of baluns, the ratio, why you need them to control currents, and various other aspects of balun installation and maintenance.  

What Is A Balun? 

A balun (balanced line to unbalanced line) is a device that transforms a balanced transmission line to an unbalanced transmission line. Baluns are hooked up to antenna systems to help electricity run smoothly from the ground to the device. The baluns turn unbalanced ground power into energy that is usable in in-home systems.  

Before moving on to specifications, let’s go over some essential terms, 

  • Current: Any movement of electric charge carriers through a wire.
  • Impedance: The measure of the opposition a circuit gives to a current when presented with a specific voltage. 
  • Transmission Line: A specialized cable or other device made to conduct alternating currents of radiofrequency. (i.e. coaxial cable).
  • Balanced Load: When the electric loads are equally divided between the two sides of the breaker box.
  • Unbalanced Load: When the electric loads are not equally divided between the two sides of the breaker box’s two sides. 
  • Dipole Antenna: A class of antennas. The conductive wire rod is designed by keeping the maximum antenna wavelength in mind. For example, if the max wavelength is 2 feet, then the rod will be 1 foot. 
  • Balanced Antenna: A class of antennas where the output and input elements are equal
  • Common Mode: Whatever voltage is common to both output terminals, causes the system to shut down if too much is transferred throughout. (output terminals -- breaker box, antenna, etc.)

Baluns work as a specific part of the electrical system. The purpose of the device is to distribute and manage common mode currents. The balun is a transmitter that sits between the ground power and the output systems. They are used for two reasons. First, baluns sort out the flow of A/C signals. Second, they make the necessary impedance transformations between the coaxial cable and balanced loads.  

What Is The Balun Ratio? 

The balun ratio is the sweet spot that gives you balanced to unbalanced load frequency. For example, if you have a 4:1, then the device has a high impedance that’s four times balanced to unbalanced impedance. The goal of the device is to lower the input impedance and maintain the output impedance. Baluns usually come in 4:1, 6:1, and 9:1, but individuals can experiment with the frequencies they’re looking to emit.  

The perfect ratio will depend on the type of coaxial cable you’re utilizing for your antenna.  

What Is Inside A Balun? 

A balun is composed of intricately wrapped metal wiring. The wiring used depends on the purpose of the balun. Sometimes, copper is utilized while other times, the manufacturers craft the wiring out of gold. All devices come in small plastic boxes with input and output connection points, no matter the material used. 

The metal is wrapped in various ways depending on the type of balun and the strength of the device. Some baluns are isolated, meaning that there is no direct connection between the input and the output. These machines have two sets of wires inside them, one on the input side and the other on the output side.  

Other devices are not isolated, which means that they have an unbalanced side and a balanced side. There are still two sets of wires inside. The difference from isolated baluns is that one side is composed of looped wire (the unbalanced side), and the other side is composed of straight wire.  

Why Do I Need A Balun? 

A balun is used to help set up antennas in your home or place of business. If you’re installing a dipole antenna or one with a wire, you’ll need a balun to balance the transmission line. When you’re not using it, the connection between a balanced antenna, such as a dipole antenna, and other coaxial feeders is wrought with issues. 

The balun helps your radio function without frequent interference. Electric systems in homes and businesses run along walls, company buildings, residential homes, objects made of metal, and through the ground. 

Without a balun, your antenna and electrical system are susceptible to interference from any outside electronic force. The electric cables that power your home and appliances go around objects made of metal, dirt, and other things that interfere with conductivity. If you choose to connect your antenna cables without a balun, you run the risk of stray currents ruining your connection and feeding you radio interference.  

Types Of Balun 

Though there are many baluns available on the market, two stand out as the most popular and commonly used, voltage, and current baluns. In the section below, you’ll learn about how the balun types work, their differences, and which work better in certain situations. 

If you’re interested in other specific types, contact an expert to see what your particular situation requires.  

Voltage Baluns 

Voltage baluns work by continually trying to force the output terminals to equal voltages. They sometimes start a phase shift between the ground and each output terminal that’s connected. The high impedance at each terminal must be precisely equal, or else the current loads will not be equal or opposite. 

The machine will always magnetize its core in direct proportion to the load voltages. Because of this, your core heating and flux density will be affected, meaning that your antenna will be less stable.  

The devices do not provide common-mode isolation, meaning that you will experience feedline reception troubles. Voltage baluns always have some sort of feedline radiation/reception because they are rarely perfectly balanced.  

Use these devices when you have a balanced system that doesn’t require much common-mode isolation. 

Current Baluns

Current baluns are the most common ones used in the electric industry today. The devices allow each output terminal’s voltage to adjust to any value needed, so long as it works for the ground power source. The current baluns add common mode isolation between systems connected at each end. 

When it comes to high impedance, current baluns are equipped to distribute the power without damaging the system. They either isolate or add impedance to control the common mode isolation. The devices cannot handle infinite power, but they are equipped to deal with extreme impedance transformations as they come.  

Use these devices for most electric situations no matter which antenna you’re utilizing unless you need a specialized setup.

What Is The Difference Between A Voltage and Current Balun? 

When considering voltage versus current baluns, there are a few key differences to consider. Voltage baluns are more simple to use and cheaper to manufacture.  If you use a current balun, you’re more likely to have a balanced load. Current baluns have lower losses, they tolerate high impedance, and they balanced variations better.

Unless you have a specific use for the device, you shouldn’t use a voltage balun. Some companies will recommend them even though they are less effective and could end up ruining your electrical system if you’re not careful. Make sure that you’re contacting a few professionals to get their opinion before deciding on the type you want to purchase.  

Depending on the type of antenna that you’re looking to install, the kind of balun will vary. If you’re looking to control the currents going through your antenna system, get in touch with a company with a surplus of background knowledge such as Moonraker.  

Popular RF Baluns To Check Out 

The number of makes, models, and varieties currently available on the market are numerous and can be confusing to individuals just getting started with installing their antenna system. If you’re looking for easy tools to help you install your antenna, we’ve highlighted the two top out of our collection.  

Though we’ve listed a couple of our favourites here, you can check out the rest of our wares on our website. Not only do we have baluns, but we also have other antennas and accessories for you to choose from.  

MB-1 — 400W 1:1 CURRENT BALUN — Best Seller & Best Value 

The 400W 1:1 current balun is a device available in the Moonraker catalogue. The balun is popular among professional and amateur radio operators. Our fair pricing system ensures that customers, no matter their financial background, can acquire the tools they need to install an antenna. The current balun is a 1:1 ratio between the input and output impedance.  

The device runs up to 400 watts. The frequency ranges from one to thirty MHz. The impedance interference is about 50 ohms. You’ll want to connect SO239 wires for the second antenna cable and brass terminals for the wiring. The small device will allow you to make one connection between your antenna and the ground power source.  

MB-1X — HIGH POWER 1:1 CURRENT BALUN — Best All Round & Best Quality 

Moonraker has a high power 1:1 current balun available in their catalogue. Clients that are looking to put more energy into their electrical system should consider the product. The machine works for both professional and amateur radio enthusiasts. We price baluns fairly to ensure that everyone can access the equipment they need.  

The device runs at 1000 watts of power. The frequency can range between one and thirty MHz. You’ll experience an impedance interference of about 50 ohms. When making the connection, utilize SO239s for the second antenna cable and brass terminals for the wiring.

When Should I Use A Balun? 

Baluns have a wide variety of occasions when they can be used. Their usage will vary depending on what electrical or antenna system you’re looking to complete. Baluns are used in a variety of electrical situations. They are commonly used to connect antennas to ground power. 

1. If you need power lines to communicate with one another smoothly.  

When you’re installing power lines, you’ll notice that there are baluns on both sides of the power cable. The difference between the power cable and other baluns is the wiring connected to the device. Power cable baluns have an external plug for the input transmission line and for the output transmission line.  

2. If your data communications transition between Cat 5, Cat 6, etc. and Twinax.

Transmission lines jump between a variety of currents depending on which speed your antenna electricity is running at. Because of this, your input and output might run on different communication currents. Cat is short for category and denotes the speed that the specific cable can carry without much radiofrequency. The lower speed category cables do not have shielding by themselves while the higher cables (6, 6a, 7) do. Because of this, the balun types need to be modified to catch the various current speeds.  

The twinax is usually utilized on the antenna side of the electric system. Twinax is short for twin axial cable, which means that the wire has two inner conductors instead of one. Because of this, the balun is necessary. When the cat cables are connected to the twinax cables, the speed of the currents are different. They ensure that the individual currents do not interfere with one another.  

3. If you need to convert video transmissions between a twisted pair and a coaxial cable.

Both coaxial and twisted cables have the same initial purpose. The devices are used to connect the various parts of antenna networks. No matter which you choose, there will be some level of signal interference. The interference means that external signals interfere with the transmission currents inside of the cable. You’ll also deal with a bit of signal leakage, meaning that signals inside the cable leak out and interfere with other electronic devices you have at home.  

The item, also known as a coax, has four internal layers. The core layer is an internal conductor, which could be made of copper or gold, and the three top layers are insulation. The final layer, made of rubber, is visible to individuals. Coaxials are popular among both professional and amateur radio enthusiasts. No matter what make of coaxial cable you purchase, there will be little variance in the interference.  

Twisted pairs are a unique cable that also works for antenna networking purposes. The devices come in two varieties, shielded and unshielded. Both types of cable are designed with two conductors wrapping around one another, hence the name. One conductor works as a forward circuit while the other is the return circuit. The unshielded versions are cheaper than the shielded versions. When you purchase an unshielded twisted pair, you risk exposing your electric system to more interference from other devices.  

Both types of twisted pairs work better, utilizing a balun to negate interference.  

4. If you’re looking to hook up your antenna, any balanced antenna such as a dipole antenna, to a ground power source.  

When you use a balun to connect your balanced antenna to a ground power source, you’re giving your system better control over the various electric currents. The balun is allowing the coaxial feeder to operate in the correct manner and make decisions as optimally as possible. The overall radiation pattern of the antenna will be affected if you don’t use a balun. Also, keeping the radiofrequency current at a minimum around the antenna transmitter will prevent issues like data mode disruptions.  


Baluns are a small but essential aspect of installing and maintaining an electrical and antenna system. To keep the currents of electricity running smoothly from one side to another, either voltage or current baluns are used. If you take apart most cables, whether coaxial or otherwise, you’ll see small baluns that help maintain the internal current balance.  

If you’re looking for a variety of baluns that you can use to install your antenna, contact our team at Moonraker today.

We are the largest stockist, distributor and manufacturer of amateur, CB, and scanner antennas and accessories in the UK. Our team works with both commercial and residential clients to ensure that their radio and antenna accessory needs are met, no matter the circumstances.

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