QRZ Forums. I have a need for a 9 to 1 unbalanced to balanced balun that I can use with a meter ft dipole that is fed with ohm line.

I can find the unun, but not an unbalanced to balanced design. We've been working with this antenna mounted at ' inverted Vee style, ends are down at about 15 feet. We've triedand baluns, but so far, the only thing that we can get to work on and 80 m is a un-un and a CMC off the tuner. I want to try a balanced 50 ohm to balanced ohm balun to see if I can eliminate the CMC and get a better match.

We are matching through a tuner. Please, don't suggest a different antenna, or other mods. W0IHDec 5, Mike I would never try and use a Balun on an open-wire fed antenna. Much better to use a proper balanced ATU. Roger G3YRO.

How To Wind A Balun

G3YRODec 5, AK5B likes this. Last edited: Dec 6, W5DXPDec 6, Center up ft, legs now Average dirt. The SWR loss in coax on m is trivial.

If you absolutely gotta use ladder-line, and the ladder-line is ft long 25ft from shack to tower, ft up the tower? At 1Kw, those impedances are an almost guaranteed arc-over.

how to wind a balun

The tuner losses will be high, the balun losses will also be high, or you will blow it up.This is interesting, but I find the description a little unclear.

I would really like to see a physical rather than electrical drawing of the set-up you are describing. I agree a physical setup is much more easy for a new ham I understand your electrical description, seeing both and the materials you use for construction will help. Thank you for taking the time to explain the process and share your knowledge.

How do I wind a 9:1 Unbalance to Balanced Balun

You are absolutely right. I added a pair of wiring diagrams. Thank you for your comment! You English is excellent and makes the use of your web site that much easier!

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I wish I had read this article earlier than this. It is excellent and would have saved me hours of work in adverse conditions. Many thanks. Hola, Leyendo tu articulo sobre la construccion de un 'balun', el cual he encontrado muy informativo, le agradeceria me aclarase una duda, cuando se refiere a la barrita de ferrita no indica cuantas vueltas recomiendas, mientras si lo hace al refiere al toroide.

En otros articulolos sobre 'balun' por regla general al referirse a las vueltas del cable de cobre sobre la ferrita suelen indicar unas 13 vueltas. Le agradecere me indique si es asi o debo de darle tan solo 6 vueltas, o sea, igual que formando la bobina sobre el toroide. Es un poco un juego de prueba-error. Hi Miguel, Your schematic and wiring diagram of the balun is very helpful. I rebuilt it after finding your article and now it works OK but I may have too many turns. I would like to see the diagram how to stack the two together, to make a Balun on the coax feed side, and a output to the antenna.

In that case I used to place a RF choke before the balun. I've never tried to place both baluns in series. Something to test in a rainy weekend. You are right! I modified the drawing with the right one. Thank you!

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Hello Miguel. May i know if you tried to use an HF dipole antenna without a balun? May i know the SWR meter reading? SWR readings do not has to be better or worse with or without a balun, but usually they are. The balun blocks, or isolate, the RF from flowing by the outter side of the coaxial shield, so you are actually tunning a two arm dipole, not a three arm dipole.In general, baluns are a very simple device and very easy to build home brewbut for some reason most people are afraid to build their own baluns.

Your balun will only work well for you if you choose the right technology and build it properly. Unfortunately there is a lot of bogus information on the Internet about which technology to use and how to build it.

It is commonly accepted that a Guanella balun may be built by winding two Guanella baluns current balluns onto a single toroid core and wiring them together is a specific way.

Unfortunately if you do it this way, it will not work. In fact it is not even a balun - at least not when used with hf antennas! Most Guanella baluns, as well as most of the instructions showing how to build a Guanella balun use just one single toroid as the core for winding the two transmission lines onto.

If you build it like this or buy one like this, you will not have a balun at all. In order for a Guanella balun to function properly, each of the two transmission lines MUST be wound on its own separate toroid core. This mandates using two cores. For higher power you would use 4 cores two pairs of two cores glued together. According to Roy Lewallen, W7EL, the main thing a balun should do is "cause the currents in the feed-line conductors to be equal in magnitude and opposite in phase, resulting in a zero imbalance current.

Notice that the balun's job is to keep the feedline balanced. Roy also gives a presentation on baluns every year at Dayton, explaining to his audience what baluns do. Once we agree on the true task of a balun when used in typical antenna applications. AND, all typical antennas are non-floating loads. Since a balun's job is to maintain balance.

In order for this type of balun to work. My New Web Site. The Cost Of. Rob Sherwood Test:. Yaesu FTdxD. Linear Amplifer. Rob Sherwood. Test Review:. Aerial L. OCFD Antenna.

how to wind a balun

My WRTC An Aerial Sponsored Expedition:. NEW Spiderbeam.I needed a simple portable HF antenna.

how to wind a balun

A long wire and some insulators is pretty easy to carry. To connect it to the radio I needed a Balun. These are such simple things but yet they cost so much from some places. A Balun is used to match a balanced line to an unbalanced line. An Unun is used to match an unbalanced line to another unbalanced line.

Balun for 40 meter band

This is a Current Balun. That means it can match a ohm antenna to a 50 feed line. If you plan on stringing up a dipole you use 2 equal lengths of wire with the Balun in the middle.

You can run the wire straight across the field or better yet use a V shape, either inverted or not.

Ferrite, chokes, and RFI

In an inverted V you raise the Balun to a high point on a mast and the elements extend down to the ground. I prefer a regular V where the Balun is near the ground and the elements extend up to two masts or trees, buildings etc nearby. Even simpler is a long wire end fed antenna. You just need a single wire and a ground rod.

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Here you need an Unun. The only difference between the Unun and Balun is how you connect the feed line. You need a good large toroid core. You will make a bifilar winding.

This simply means you wind 2 wires at the same time, lying flat and equally spaced. Many people use 2 different colors of wire but its easy enough to figure out with an ohmmeter. After you are done winding the coil coat it with glue or shellac to keep it together. Now strip all 4 leads and connect your meter to one start and one end lead.

These will go to the binding posts.

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Now connect the remaining 2 leads together. This is the center tap of the coil.Sleeve Balun shows how a sleeve adds impedance, useful for VHF and higher baluns.

How To Wind A Balun

Receiving Common Mode Noise shows how lack of a balun can contribute to system noise it applies to transmitting antennas as well. Balun and Core selection for transformers and baluns. Transmitting baluns on testing transmitting baluns. Commonly published information tells us winding a choke or balun on a toroid with this special winding technique increases common mode impedance choking isolation of an turn balun on a pair of 65 material ferrite cores:.

Shunt capacitance is not always a bad thing! While the results vary with the core and number of turns, the more-difficult "split winding" will often just shift peak performance points higher in frequency. Performance in the HF range and lower could actually be decreased with the extra effort resulting in a poorer HF balun.

Common mode impedance, if the impedance is primarily inductive, increases when a slight amount of parallel capacitance is added. Shunt capacitance does not always, as is often claimed, reduce performance by "leaking" RF around a choke. The rule is simple. With any parallel L and C neglecting lossesimpedance always increases unless the parallel capacitive reactance in ohms is less than half the value of the inductance in ohms. With a choke winding impedance of j with an added parallel -j capacitive reactance, the combined impedance would be -j Impedance is the same value, only the sign changes!

Any value of capacitive shunt reactance higher than -j less capacitance value would actually increase choke isolation! There are many "improvements" we just blindly accept from reading articles, because on the surface they seem to make sense. This dispels one of the myths about baluns. Another common myth is the widely accepted claim moving a choke balun to a lower common-mode impedance point of a circuit, such as the input of a tuner, improves balance or balun performance in the system.

You might be surprised!My website uses JavaScript for menus etc. It is currently disabled in your browser! Please re- enable it for full functionality. All rights reserved worldwide. No part of this publication may be used without permission from the author. A " BalUn " is bi-directional adapter between a bal anced device and an un balanced device. Twin-lead feedlines and dipoles are "balanced" two signal conductors, with equal-but-opposite current: symmetrical.

Coax cables, and the antenna port of a typical sold-state transceiver, are "unbalanced": one signal conductor that is referenced to ground a. Baluns other than those with a transformation ratio, also act as impedance transformer.

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As the name suggests, an " UnUn " is bi-directional adapter between two un balanced devices. I am not a expert real or self-anointed of baluns, impedance transformers, transmission lines, transmission line transformers, etc. Far from it. So, rather than writing here what my interpretation is of what they are, how they work, how to build a good one, etc.

The BL1 uses a two-hole "binocular" ferrite core a. It can be wired as or The BL2 uses two stacked ferrite cores of the same type, for increased power handling capability W. It includes a DPDT slide-switch for changing between and This type of ferrite core has an advantage compared to an equivalent "single hole" ferrite ring toroid or a ferrite rod: about half of the winding wire is inside the "tunnels" through the ferrite block.

Broadband transformers in transmitter power stages often use such cores, or two cylindrical cores side-by-side. There are many different ferrite material mixes. Important parameters from the data sheets ref. Frequency" and "Core Loss vs. AC Flux Density" curves. Note that the permeability of ferrites varies with the magnetic flux level.

Hence inductance of a coil or transformer made of such material will change with the power level. Power handling limited by core losses. These core losses primarily hysteresis loss and eddy-current loss roughly increase with the square of the flux density in the core, at any frequency. Ferrite RF transformers must be operated at a core flux-density level that is commensurate with the volume and cross-sectional area of the ferrite. Conversely, the core dimensions should be adequate for the power level.

The maximum flux level is driven by the loss tangent dissipation hysteresis loss factor of the ferrite mix. If that flux density limit is exceeded, a runaway effect causes the core temperature to rise very quickly and ultimately and possibly violently destroy the core!

Cores can be stacked to increase power handling capability. However, stacking cores also increases the total inductance of a transformer. Furthermore, a larger core also results in larger inductance, compared to a smaller core of the same material. The permeability of ferrite material changes significantly when flux is increased.

This may lead to unpredictable behavior when higher power levels are involved, and saturation sets in which happens at much lower levels then in iron dust cores, but those have much lower permeability. This may also explain observed differences in behavior when exciting a circuit with an antenna analyzer that outputs no more than several mW, compared to full power of a transmitter.

Note : the balun can also be used as a 1.QRZ Forums. Tags: balun. Hello all, I am very grateful for the experiments of the amateur radio friends, including how to make an HF balun. K7TRFFeb 27, YF8RQN likes this. I've been hunting for days for just such a chart.

Thank you, K7TRF! When it comes to balun designs and DIY, the internet is like drinking from a fire hose. If you wish, what is the maximum power capability, if I use RG 58 cable with Teflon base material? Hopefully this information can be used by other radio amateurs, sharing permissions with others, nice to meet you David, de YF8RQN, Last edited: Feb 28, K7TRFFeb 28, Well, thanks David for the explanation and response of this treath. Here is a scan on my NanoVNA. To bench test them, we ran 2 in series, so, 50R : R: R: 50R.

All in all, they worked as well as the one commercial unit we has connected. The qrz post about the event is here You must log in or sign up to reply here. Show Ignored Content. Share This Page. Your name or email address: Password: Forgot your password? Register for a free QRZ account.