Applications [ edit]
- Radio and television [ edit] A 75-to-300- Ω balun built into the antenna plug. In television, amateur radio, and other antenna installations and connections, baluns convert between impedances and symmetry of feedlines and antennas. [4] ...
- Video [ edit] Baseband video uses frequencies up to several megahertz. ...
- Audio [ edit] Three audio transformers; two of them baluns. ...
What is the function of a balun?
What is Balun?
- Balun is a device which connects balanced transmission line to unbalanced transmission line.
- Balun is the short form of Balanced-Unbalanced. ...
- Impedance transformation
- Balanced to unbalanced transmission Balun Types | Types of baluns with their applications Let us understand different types of baluns with their applications. ...
- Sleeve balun or Bazooka balun
What balun do I Need?
Yes, a balun is needed. All balanced antennas such as dipoles, Yagis and hexbeams that are fed with unbalanced feed lines such as coax, require a choke balun. Without a choke balun, common mode RF currents flow on the outside of the coax making the feedline act like another antenna.
When to use a balun?
When to use BALUNs? Baluns are usually used to feed dipole antennas with 50-ohm coax and to transpose from ladder line feeding a multi-band antenna to the unbalanced input of an antenna tuner. The primary reason for using a balun at the feed point of a dipole antenna is to prevent RF currents from flowing on the outside of the shield of the coax feeding the antenna.
Do I need A balun on my TV antenna?
The primary reason for using a balun at the feed point of a dipole antenna is to prevent RF currents from flowing on the outside of the shield of the coax feeding the antenna. RF current on the outside of the coax shield causes the shield to radiate.
Do I need a balun?
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.
What is a balun?
Definition of balun : a radio device for converting from a balanced to an unbalanced line and usually used at high radio frequencies.
What is a balun Why do we need that in dipole antenna?
BalUn means: Balanced to Unbalanced. This enables us to adapt an unbalanced fed system (coaxial cable) to a balanced antenna system (dipole antenna). The main reason for using a BalUn is to ensure that the coaxial cable does not become part of the antenna system and therefore radiates with it.
Is a balun needed for a dipole antenna?
The use of a balun will prevent the coax radiating any power or picking up any noise. In many practical situations it is possible to operate the dipole satisfactorily without one, but there may be a slight increased risk of interference if one is not used. Simple baluns can be bought from antenna suppliers, or made.
Where do you put a balun?
In most cases, baluns are installed as close as possible to a balanced-to-unbalanced transition point. Current baluns allow each output terminal's voltage, with respect to "ground" or chassis, to float to any value required to provide equal currents to each feedline conductor.
Does a long wire antenna need a balun?
The balun must be a high quality current balun, not an unun or voltage balun. It should be a 1:1 ratio with high common mode impedance and high voltage breakdown. The coaxial feed line, since it operates at high SWR, should be high quality and as short as possible.
Does a BalUn reduce noise?
Whilst a balun is usually associated with reduced unwanted transmission line radiation (eg. from the feedline and power cord), a balun can also help minimise unwanted noise picked up by your feedline.
How do you wire a BalUn?
1:249:41Connect CCTV camera to DVR using video baluns and UTP cableYouTubeStart of suggested clipEnd of suggested clipCables then we need to connect them to the balloon. One cable in the plus and one cable in the minusMoreCables then we need to connect them to the balloon. One cable in the plus and one cable in the minus. Just press the buttons. And push the cables in twist the pair and secure it using a cable.
What is the purpose of a 1 1 BalUn?
This enables us to adapt an unbalanced fed system (coaxial cable) to a balanced antenna system (dipole antenna). The 1:1 BalUn 800 Watt is suitable for QRO use. The main reason for using a BalUn is to ensure that the coaxial cable does not become part of the antenna system and therefore radiates with it.
Is a full wave antenna better than a half wave?
It's length (half of the wavelength) gives you the better performance than other lengths..... It may be gain, efficiency, directivity, return loss, etc..... I got the following picture from a book. I think the gain of the half wave dipole is higher than the full wave length antenna.
Do I need to ground a dipole antenna?
Answer: No. The 1/2 wave antenna (also called a dipole antenna) is built of two 1/4 wave elements that interact with one another to launch the electro-magnetic wave. It does not require a ground plane to work efficiently.
How high should dipole be?
Recommendation. For best results, dipoles should be at least 1/2 wavelength above ground level. For the lower bands, especially 160-40 meters, this can become impractical--place your dipole as high as your situation allows.
What is the purpose of a 1 1 balun?
This enables us to adapt an unbalanced fed system (coaxial cable) to a balanced antenna system (dipole antenna). The 1:1 BalUn 800 Watt is suitable for QRO use. The main reason for using a BalUn is to ensure that the coaxial cable does not become part of the antenna system and therefore radiates with it.
Do I need a balun on my TV antenna?
You need a balun to make sure that the antenna connects to coax cable. Your antenna's balun could look like the one above, or it could be a small box. Either way, there is a connection point somewhere. Somewhere, there are wires that come from the antenna and connect to a coaxial cable.
What does a balun look like?
11:3634:15Baluns: What are they, and how they work - YouTubeYouTubeStart of suggested clipEnd of suggested clipThose are balanced lines. If you look at them both sides is the same coax is unbalanced that centerMoreThose are balanced lines. If you look at them both sides is the same coax is unbalanced that center conductor and that shield looks very different bite.
What does a CCTV balun do?
What is a balun? A video balun is a wire connector device that allows UTP cable (such as CAT5) to transmit the video signal from CCTV cameras instead of using coaxial cable such as RG59.
What is balun cable?
The term balun is an acronym for BAL anced-to- UN balanced. This usually means connecting a balanced load such as a dipole antenna to an unbalanced input such as 50 Ohm coaxial cable. The shield side of the cable is usually grounded. The balun belongs to a class of devices known as “transmission line transformers”.
Why use baluns on antennas?
Baluns are usually used to feed dipole antennas with 50-ohm coax and to transpose from ladder line feeding a multi-band antenna to the unbalanced input of an antenna tuner. The primary reason for using a balun at the feed point of a dipole antenna is to prevent RF currents from flowing on the outside of the shield of the coax feeding the antenna.
What is a balun transformer?
The balun belongs to a class of devices known as “transmission line transformers”. Transmission line transformers are formed by winding bifilar turns, multi-filar turns, coaxial cable, or stripline cable (two strips of the flat conductor with a dielectric material between the strips) on a high permeability core.
Where is the balun grounded?
A current balun is best for this use. Usually, the shield of the coaxial feedline is grounded somewhere near the input. Preferably, it will be grounded before the coax enters the shack such as at an antenna switch. If the length of the coax is ½ wavelength from the ground point to the antenna feed point, the outside shield will reflect ...
Why are balanced output terminals isolated from unbalanced input terminals?
Because of the high impedance of the winding, the balanced output terminals are isolated from the unbalanced input terminals. There are two general classes of baluns: the voltage balun and the current balun. The voltage balun forces equal voltage across the two sides of a balanced load and the current balun forces equal current through ...
What is a balun?
A Balun is used to "balance" unbalanced systems - i.e. those where power flows from an unbalanced line to a balanced line (hence, balun derives from bal ance to un balanced). As an example, consider a coaxial cable connected to a half-wave dipole antenna shown in Figure 1.
What is balun in transmission?
The solution to this problem, however you come up with it, is a balun. A balun forces an unbalanced transmission line to properly feed a balanced component. In Figure 1, this would be done by forcing IC to be zero somehow - this is often called choking the current or a current choke.
Is a balun easy to understand?
Baluns are pretty tricky to fully understand and at first pass can be difficult to grasp. However, suffice it to remember that a balun forces unbalanced lines to produce balanced operation, despite their inherent asymmetry.
What is balun transformer?
Introduction: • Balun is a device which connects balanced transmission line to unbalanced transmission line. • Balun is the short form of Balanced-Unbalanced. It is the device which matches two different impedances. For example, balun transformer connects transmission feed line with antenna. In this application it converts impedance ...
What are the different types of baluns?
It describes different types of Baluns viz. L-C balun, transformer balun, Folded balun, coaxial balun, microstrip balun etc.
What does a balun mean?
General Info on Baluns. Balun is an acronym for BAL anced to UN balanced, which describes certain circuit behavior in a transmission line, source or load. Most communications applications deal with two-terminal sources, transmission lines, and loads.
What is a balun in electrical?
Current baluns are universal devices that work with balanced or unbalanced loads equally well. Current baluns add common-mode isolation between systems connected at each end. While traditionally used as baluns, they work well as broadband phase-invertors or as an un-un.
What baluns are used for antenna tuners?
For antenna tuners or systems with high SWR, we have a special balun. This balun uses high-voltage wire and has excellent performance at very high SWR. Even standard DXE baluns are better than many competing baluns, because many competing baluns use thin enamel for wire insulation. Our standard Teflon insulated wire does not fail unless voltage significantly exceeds 7,500 volts, while competing baluns using enameled wire fail at less than 25% of that voltage! That means, for the same mismatched differential load impedance, our standard balun can handle sixteen times the power of enameled wire baluns before arcing in balun windings!
How long should a dipole be for a balun?
Although it may not seem logical, for 160 through 10-meter operation, a dipole around 220 feet long may actually help antenna tuner and balun performance, especially on lower frequencies. This is because standing waves on the transmission line transform or change reactance and resistance presented to the balun and antenna tuner. The coaxial cable from the DX Engineering 1:1 Tuner Balun to the tuner should be kept short; 10 feet or less is best. The recommended 300-Ω ladder line provides better overall impedances at the tuner and balun, as opposed to typical 450-Ω ladder line. Conductor resistance dominates transmission line losses below VHF, so choose the largest diameter conductor you can for a given transmission line size and impedance. Do not substitute smaller conductor television-style feedline to save money. Losses will increase.
How many ohms does a balun have?
As the operating frequency changes, balun load impedance can range from several thousand ohms to a few ohms. 2. Most antenna tuners work best into moderate to high impedances, rather than low impedances. Most baluns inside antenna tuners step the antenna impedance down.
Why are current baluns better than voltage baluns?
Current baluns are the balun of choice in all but very specialized situations, because they work better than voltage baluns in most real-world systems. In the case of a 1:1 ratio current balun, core flux density or "magnetizing stress" on the balun core is independent of load impedance or load mismatch.
What is voltage balun?
Voltage Baluns. Voltage baluns always try to force the output terminals to equal voltages. They sometimes introduce phase shift between each output terminal and "ground". If the impedance presented at each terminal is not exactly equal, feedline or load currents will not be equal and opposite.
Why are baluns important?
Baluns are important because many types of antennas (dipoles, yagis, loops) are balanced loads, which are fed with an unbalanced transmission line (coax). Baluns are required for proper connection of parallel line to a transceiver with a 50 ohm unbalanced output. The antenna’s radiation pattern changes if the currents in the driven element ...
What is the simplest balun?
This is the simplest voltage balun, consisting of two coils of wire connected as shown below. The coils may use an air core or a ferrite core. Current flowing through the lower coil induces an equal and opposite voltage in the upper coil.
How is a balun made?
Often a current balun is made by winding coaxial cable into a coil, with or without a ferrite core. The load impedance is not changed by the balun. The inductive reactance of the windings prevents common mode currents from flowing and ensures a balanced output.
What is a balun transformer?
What is a balun? A Balun is special type of transformer that performs two functions i.e. impedance transformation and balanced to unbalanced transformation. The term balun is a contraction of “ ba lanced to un balanced transformer”.
How many windings are needed for a 4:1 balun?
6 windings on 3 cores are required to construct a 4:1 current balun. This balun consists of a 1:1 balun followed by a 4:1 balanced-to- balanced current transformer. The windings on the 1:1 balun should have at least an inductive reactance at least 10 times greater than the input impedance.
How many pieces of wire are needed for a 300 / 75 ohm balun?
A practical 300 / 75 ohm balun would consist of four pieces of 0.4mm wire wound 2 1/2 turns through a balun core (look a bit like binoculars). In so doing we have achieved our two goals,
What wire do you use for a transformer balun?
Transformer Baluns use solid wire, preferably enameled, for the windings. For transmitting applications the wire should be #14 or larger. A 1.5 inch diameter ferrite/powdered iron core is sufficient for powers to 100 W. For QRO operation, use a 2.5 – 3 inch diameter core. Select the proper core material for the desired frequencies of operation, For HF baluns, 6 – 8 turns of wire around a toroidal core is sufficient. Air core baluns will need 10 – 20 turns.
Why is the word "balun" used in the word "balanced"?
The balun word originated from the terms balanced/unbalanced because it can convert an unbalanced signal to balanced. With balanced signals, it's possible to transmit the signal further away because it's less susceptible to external interference.
What is a video balun?
A video balun is a device used to adapt the type of connection to allow the use of UTP (Unshielded Twisted Pair) cable to transmit the signals from an analog camera. By using a video balun it's possible to replace the traditional coaxial cable such as RG59 or RG11 and use cat5 cables to transmit the video over long distances.
What is a passive balun?
The passive balun is non-powered and just converts the unbalanced to balanced signals so it's possible to transmit the camera analog signals over the Cat5e cable. An active balun is powered and can convert and boost the unbalanced signal to balanced signals and transmit it to long distances over the Cat5e cable.
How long can a passive balun run?
With passive balun, it's possible to run cables for around 200 to 300m depending on the type of analog signal and the quality of the cable and balun that's used.
How many baluns are there in a CCTV system?
The following picture shows some passive baluns used on a CCTV installation. As you can see, there's one pair of passive balun per camera. The baluns always work in pairs, one is connected to the analog camera and the other one is connected to the DVR do convert the signal back to unbalanced.
What type of cable is used for a CCTV balun?
The picture shows the types of cables used with a balun for CCTV. A pair of wires are used to connect the UTP cable to the balun and a BNC connector is used on the coaxial cable to connect to the other end of the balun.
What is a balun for CCTV?
Video balun for CCTV (how it works) You can use a video balun for CCTV to convert from one type of cable to another. This type of device is very common on video surveillance projects that use analog cameras and DVRs (Digital Video Recorders).
Which balun is the most commonly used?
7a. Overall, the 1:1 balun is the most frequently used balun.
What does "balun" mean?
About the word “balun”….It means “balanced-to-unbalanced ”; Guanella (a Swiss engineer in 1944) needed to match a balanced (push-pull) amplifier to an unbalanced load; hence the name. However, these days we generally are going unbalanced-amplifier to balanced-antenna load.
How to make a 4:1 Guanella balun?
6a. We can make a 4:1 Guanella-balun by connecting two identical 1:1 Guanella baluns such that the inputs are in parallel and the outputs are series connected per either the ARRL’s 2007 Handbook or Antenna-book ; a comment that neither book has any text on the importance of the transmission-line’s characteristic-impedance.
What is a 1:1 balun?
A different 1:1 balun is a “Ruthroff-balun”; named after its Bell-Labs inventor in 1959. Another name for the “Ruthroff-balun” is “voltage-balun”. As I see it, the voltage-balun generally is inferior to the Guanella-balun. 6a.
What is 1:1 Guanella?
The 1:1 Guanella-balun is the basic building block for other types of types of Guanella-baluns or ununs (a Guanella-unun is just a Guanella-balun with the grounds in different places; a similar statement for Ruthroff-ununs cannot be made). Also, I’ve included ‘background’ info, which I thought may help in understanding.
What is a current balun?
The current-balun (Guanella) puts equal current into/out-of its output terminals; highly desired feature. The voltage-balun (Ruthroff) puts equal magnitude voltages at its output terminals. 11. It is important to comment on the impressive frequency range of a well-designed current-balun.
Can a Guanella balun be reversed?
6c. The Guanella-balun can be reversed. So, if matching an unbalanced 50-ohm input to a balanced 12.5-ohm load for a Yagi beam, let the balun’s transmission-line have a characteristic-impedance of 25-ohms.
