Baluns, ununs and chokes: a complete mess in ham practice.

How to choose the right balun for the antenna?

(Informal, but professional!)

End of confusion – a guide to selection and application

If you’ve ever scratched your head, wondering when to use a 1:1 balun, when a 49:1 unun, and why the hell you need a „choke,“ you’ve come to the right place. In fact, there’s no magic involved – it’s all about mode matching and impedance transformation.

Here I’ll add that I’m the self-proclaimed godfather of ununs and chokes (they sound even cooler to me in Bulgarian than the originals) – there are still no suitable words in Bulgarian. The genealogy of ununs is similar to that of baluns, and a choke is a choke.

Part 1: Modes and Roles – Balanced vs. Unbalanced

It all starts with what kind of antenna you are feeding and what kind of cable you are using.

Balun vs. Unun – what is the difference?

Baluns and unununs are transformers that serve to match the power mode (balanced/unbalanced) and/or impedance matching.

Part 2: The coefficient – ​​which one is for where?

Each transformation coefficient has a specific and different purpose depending on the antenna for which it is used.

A brief overview of the most common transformers

Tip: The standard choice for EFHW is 49:1, and 64:1 is for installations where the antenna is mounted lower or near objects that increase the impedance. The difference is often insignificant and can be corrected by the built-in tuner. For POTA/SOTA activation, 64:1 seems to be a better choice because in most cases the situation is not known in advance. But even then we can never be sure – a great place to deploy the antenna may be found.

Part 3: The Choke – the Shadow Hero (HF Choke)

A Coaxial Choke or Shortwave Choke Coil (HF Choke) is a simple but extremely important device whose purpose is to block unwanted currents flowing on the outside of the braid (screen) of the coaxial cable.

Where is it most effective?

The most effective location for the choke is as close to the antenna as possible.

• At the antenna: It isolates the antenna from the feed line, ensuring that the coaxial does not radiate. A critical and essential choice.
• At the transceiver: It acts as a secondary line of protection. Filters residual currents and prevents radio frequency interference (RFI) in the station as a whole (transceiver, computers, audio and USB cables).

The myth of the additional choke: There are legends that if your 1:1 balun is a high-quality current balun, there is no need for an additional choke to improve the efficiency of the antenna. But if you have RFI problems, a secondary choke before the transceiver will probably do an excellent job. If not the neighbors, at least the transceiver will thank you.

Part 4: Power and Materials

We can’t help but touch on the topic of ferrite cores – a favorite topic of every radio amateur!

Ferrite and power

The size of the ferrite core is directly related to how much power the balun/unun can handle before it saturates or overheats.

• Saturation: If the power is too high, the ferrite saturates, its permeability μ drops sharply, which leads to a sharp increase in SWR and overheating.
• The solution: A larger core volume (e.g. FT-240) raises the saturation threshold and allows operation at higher power. Two or three smaller toroids can also be glued together for the same purpose.

Ferrite Selection (Type 43 vs. Type 61)

Conclusion and conclusions:

1. Calculations are extremely necessary and important, but never rely on them too much – check what kind of antenna and balun you have created using a suitable device or, in extreme cases, even the SWR meter of the transceiver. Adjust the antenna in place.

2. The most important thing is to choose the device according to the type of antenna and the purpose:

• for isolation – balun 1:1,
• for reducing unpredictable impedance to the impedance of the cable or transceiver, or for multi-band vertical antennas – unun 9:1 or 4:1 (it is best to test with a device);
• for direct matching of a resonant unbalanced antenna to the transceiver – unun 49:1.
• for direct matching of a resonant unbalanced antenna to the transceiver under adverse conditions (presence of nearby objects, inability to raise the antenna high, etc.) – unun 64:1.
• so that both neighbors and equipment love you – you add Choke!

3. Leave the antenna slightly longer than calculated – it is always easier to cut than to splice during the setup on site.

4. I recommend testing the baluns and chokes on site with suitable resistors, a substitute for the corresponding antenna – 50, 200, 450, 2450 and 3200 (I am sure you will find what resistors to connect in series for the tests).

5. Last but not least: I am sure that many hams will say “I work with resonant antennas and I don’t need baluns, chokes and chokes!” and whatever else. True, everyone makes the choice for themselves. In my antennas I use. Always! I try to squeeze out maximum efficiency, to work with low powers at long distances. And despite the low power, I don’t want my neighbors to know when I’m on the air!

With this knowledge, you are armed to successfully select and construct your baluns, ununs, chokes, and antennas!

Материалът Balluns, ununs and chokes: complete nonsense in ham practice. е публикуван за пръв път на Галя и Тони - Галанто.

Yaesu FC-80 vs Yaesu FC-90

The Yaesu FC-80 and Yaesu FC-90 are automatic antenna tuners designed for the Yaesu FTX-1 Field QRP transceiver, but they are designed for different types of antennas. The FC-80 is designed to mount directly on the back of the transceiver for use with antennas terminated with 50 ohm coaxial cable and has an SO239 connector, while the FC-90 is a stand-alone tuner for Long Wire (LW) and other unbalanced 50 ohm antennas.

Yaesu FC-80 vs FC-90 Comparison

 Which tuner should you choose?

Your choice depends on your working style and the antenna setup you plan to use with your FTX-1 field radio.

Choose the FC-80 if:

• You primarily use traditional antennas with coaxial cable to the transceiver: dipoles, verticals, G5RV and the like, and want the most compact and integrated configuration possible.
• You want the convenience of a tuner that mounts directly to the back of your FTX-1 Field transceiver for a hassle-free, portable all-in-one unit.

Choose the FC-90 if:

• You use a Long Wire (LW), end-fed or other unbalanced antenna that requires an unbalanced antenna tuner.
• You don’t mind a separate external tuner to get the flexibility to use it with a wider variety of cable antennas.
• With a control cable as long as the coaxial cable, you can to place the tuner next to the antenna itself.

I hope this information was useful to you.

I would be glad if you would share this or something else in the comments. If you already have personal experience and impressions, this would be invaluable for other radio amateurs!

73 es BST DX

Материалът Yaesu FC-80 vs Yaesu FC-90 е публикуван за пръв път на Галя и Тони - Галанто.

Making an antenna is a simple job that is described by three activities:

• Cutting iron and cables;
• Pilling, etc.;
• Screws and nuts.

(This is also how you write a book – you press keys in a certain sequence.)

In the Faraday cage of channel 64

Very good fishing!

Why are the large antennas external and „fishing very well“?

(And they also cost quite a bit because they are Western made, most of them.)

1. Because there is a very long piece of iron on them and as such you can’t take it into the kitchen, and for that – outside.
2. You try to raise it as high as possible, because one always wants to climb up – to Everest, to Botev, to Cherni vrah or at least to Kopitoto (the restaurant). If possible by car – ideal.
3. „Finds strong“ because at the highest possible lift, it provides signal reception with better detection of fresnel zones. Thus, the signal has a better intensity than if the antenna is seven to eight meters or more down.
4. A large part of the offered company antennas have an amplifier right on the vibrator and the feeder to the TV goes from there. Infinitely correct solution. However, the amplifier is subjected to all kinds of wonderful outdoor conditions. His life will not be very long.

Why are large TV antenna structures more pleasing to the eye than doing work in the advertised frequency range – for example, from 21-69 channels? Because:

1. If the vibrator has a wave resistance of about 75 ohms for 650 MHz, then the same vibrator (the antenna is the same) for 490 MHz is about 35-40 ohms, and for 818 MHz it is 110-115 ohms. The example with 490 and 818 MHz is a real Sofia broadcast and comes to show that if you read the inscription on the box for a 75 ohm TV antenna, then this is true for the middle of the range or somewhere along it. From here on, the reconciliation and attempts to do so go to …
2. All distances between vibrator, directors and reflector are frequency dependent (specified) and as such the antenna will be directed for one and one or two neighboring frequencies, but for the rest of the frequencies in the range only the vibrator will work as a simple single dipole antenna (and the one with unclear wave resistance). Salvation comes from lifting up.

Yes, I have also made a 7-element antenna, but it was only for 145 MHz and it was a big struggle to set it up. For range, it is simply unthinkable. There are devices with matching stages filled with capacitors and coils for electrical shortening or lengthening. Your TVs are certainly not one of them.

3. Logoperiodic antennas really work in a wider range, but they hardly work with more than two to three elements for the different frequencies, because, alas, the laws of physics apply to them too. For comparison, a well to excellently tuned 3-element Yagi antenna gives about 5-6 decibels of gain. However, if one has a penchant for disobeying laws, one can get from the logperiodic 12 to 18 decibels. If the parliament votes to repeal these laws, then things will fall into place, but they don’t want to!

The main influence on reception is the phenomenon of interference waves, which occurs in all cases when there are ground obstacles and objects (even if they do not block) in the path of signal propagation, such as a block, a house and even an iron barrel for collecting rainwater . I have briefly described this in „Methodology for finding a place for a room „antenna for digitalTV„. It is published and the title is easy to find.

The other main thing is that the cable (feeder) must have a length multiple of half the wavelength (λ) multiplied by the shortening factor and the condition must be met for all frequencies at which television is received – in most places in Bulgaria there are three. What happens if this is not met? An excellent result is obtained (ideal option) or nothing is received regardless of the antenna, clipping or reception of some channels, and the others are bad. Such examples – as many as you want.

The case of feeder length multiple of λ/2 is valid when the arm/arms of the dipole are of length λ/4 (to be precise – 0.253 λ to be 75 ohms). But this dipole is for one frequency and for higher it will be long (ie, non-resonant length) and for lower frequency it will be short – also non-resonant. Then what – when the dipole is longer, the feeder must be shorter for the configuration made in this way, and when the dipole is shorter – the feeder must be longer. When these three cases are nicely „mixed“, at the output of the already made antennao-feeder device must output a signal at the three (or whatever is calculated) frequencies with the maximum possible amplitude of the voltage induced in the antenna. The solution to the problem is easy. It took me personally about two or three months ahead of time.

To receive dirtier signals, a full-wave dipole can be created, i.e. the arms are of length λ/2 and then the feeder should be of length n*λ/2 -(+) λ/4 and not the shortening factor is forgotten. Again, it works according to the above logic – with shorter arms, a longer feeder or vice versa, and all these conditions must be satisfied in one configuration (one antenna-feeder device).

I have personally achieved the following results with my self-made passive (without any amplifiers) antennas (with my wife’s permission, of course!):

• Village Padesh, Blagoevgradsko. This village does not receive over-the-air television, and there were news reports that people were „rioting“ due to being deprived of this option. I made a corresponding device and went there – all three multiplexes came out. God’s work.
• Village Kremenik, Dupnishko, which is located above the Dyakovo dam. Also people don’t watch broadcast TV because of impossibility. The channels from the three multiplexes came out there as well.
• Village Zivkovo, Ikhtimansko. The neighbor of my methodical supervisor in fishing tried the variants of lifting up a large antenna with the assistance of a technical digitization team. The result is a switch to an alternative provider (cable, satellite), accompanied by a certain amount of expletives. At the same time, my fishing guru watches with a passive antenna my craft, which is located in the room.
• Village Beli Iskar, Samokovsko. „Kofti“ place with more than 70 meters of overhang from a land massif in the middle of a 3.5 km route, through which the overhang does not pass even a third Fresnel zone (ie, what is reached from the fifth). There was an external new logoperiodic antenna erected, which, however, did not receive the BNT package, which was received on 722 MHz, and the btv, nova tv and tv7 package on 626 MHz was received with periodic interruptions. After installing an amplifier (amplified at mach) the reception got better. I was not satisfied with the situation. I made some effort and it is now received with a room antenna without an amplifier.
• And I can no longer remember how many more places – the village of Vladimir in its lowest part, Kocherinovo, the village of Gorni Dabnik Plevensko, the village of Varvara (between Tsarevo and Ahtopol) in its low part below the center, etc.

For Sofia and its surroundings, there are also no problems with reception, regardless of whether it is the first or last floor, with a view or on the opposite side to the transmitter, and I show it in a car service (car workshop), which is practically a pure „Faraday cage“ – the whole inside is metal construction with appropriate grounding (all metal columns are in the ground). Reception is on channel 64 – Vest TV.

If you think what has been written so far is incredible, read the article again.

Otherwise, the spread of VHF is „God’s work“!

Материалът Outdoor or indoor antenna? Should we buy or make? е публикуван за пръв път на Галя и Тони - Галанто.

Room antenna for „digital“ TVInstead of introduction

…as my teacher Nikola Lazarov used to say from that school, which is located at the intersection of „Shipka“ and „Brothers Evlogi and Hristo Georgievi“ streets – „the spread of VHF is God’s work“.

Why God’s work? Well, because in the ideal version, in direct line of sight, communication (reception) goes out, and in the presence of obstacles, interference waves are received.

Interference (superimposed) waves are complex in terms of signal intensity, which are characterized by pronounced minima and maxima in space, caused by the different lengths of the traveled path in the propagation of the reflected signals and arriving at the reception point with a relative superposition of the phases (maximum signal ) or out of phase (almost no signal). Due to the complexity of the obstacles (location of apartment blocks, buildings, etc.), the signal does not always follow the logic of minimum-maximum at a relative distance of one wavelength, which as an example for the 40th channel at 626 MHz is about 48 cm. The signal it can „appear“ a meter, two or more, and in the most unexpected place for you.

So:

1. Without watching the TV, the antenna location is not searched (turn it towards you).

2. If the programs do not appear during automatic search:

2.1. Enter channel search (scan) mode.

The mode on most receivers is in the menu under „auto search“. You need to know for your area the broadcast channels as a number corresponding to frequency.

For Sofia and its surroundings, it is broadcast on channels 23, 40, 52 and 64.

2.2. Put on a channel number that you know broadcasts for the area.

If you don’t know them, they are on the site (page) predavatel.com.

2.3. Start slowly moving the antenna around where you have determined (your wife has determined) that it can stand.

Not only to the side, but also up and down – the signal can also appear on the floor. Monitor the signal level and quality of the given channel until the maximum readings are found.

Practice showed that a signal appeared at a place next to the inner window sill and at a height of 10 cm from it, otherwise when an antenna was placed on the sill itself, the signal was with a level of despairing zeros in strength and in quality. This happened in the village of Bistrica – Sofia, where almost no one watches digital broadcast television.

2.4. Do a similar check for the other channels.

2.5. Find the compromise antenna location for all channels.

Found that even when moving the antenna 1-2 cm, some channel can be lost or received with „cut“. For me personally, such amusements in finding a place have lost me more than 2 hours before achieving a result of „bravo“. Take your time and don’t despair. In five to ten minutes, something else can be „done“, but not finding an antenna location with a „junk“ signal.

If it didn’t work for you after applying this methodology even with an antenna made by the person who wrote this reading (see the photo and contact him if interested), don’t rush to buy external large antennas. They amplify and target 1-2 channels (frequencies) but not all broadcast. In addition, the moment of finding the right place (see interference waves) also applies to them, and in the most general case it is determined, but not by you (a working-not-working chimney, some kind of pylon, etc., because you will not be drill the shingles in the middle of the roof, right?). And with direct visibility, there is no need for these focuses. With „my“ antenna from Ovcha Kupel, I receive the 41st and 57th channels (BTV and BNT – nine programs) broadcast from Mount Botev, which is about 140 km away, most calmly without an amplifier.</ em>

God’s work.

…otherwise we know that the cable and satellite operators also feed children!

Материалът Methodology for locating a room antenna for „digital“ TV е публикуван за пръв път на Галя и Тони - Галанто.

Photo 1. This is the general view of the antenna that should be obtained, without any additional embellishments. Many TV viewers (not talking about cable) have faced the problem of „catching“ one or another program, but not and all from the same position and with the same antenna.

So how does the whole story begin.

In the beginning it was beer…

It started like all good things – word for word at the table!

I have a friend who is called Anton, LZ3AI, or when he goes to work – something else. So he took a scheme from some wise men, realized a similar antenna (but not particularly suitable for the current television broadcast) and offered it to a neighbor who follows all the series about Ronaldo, Rivaldo and the suffering Maria.

He offered her this antenna, because they cut the cable of the grandmother and the characters from the series were left without empathy.

However, when the grandmother saw the antenna, she said that she would not put such rolled cans of canned tomatoes on the terrace, even though they „caught“ everything. I set about recalculating the antenna and the corresponding attempts to achieve what you will read next.

If you tap on the photos (but not with a hammer, but with the mouse), they will enlarge so that you can view them calmly. Then you close the newly appeared window to continue with the fascinating reading.

I don’t want people to be left with the belief that this antenna was born „just like that“ and exactly this size of the shoulders was established only by calculations. It was a six-month long trial process on already empty beer cans that gave an answer to the question of how long they should be – exactly 9 cm, not 13, 12, 10 or 8 cm. Anyone who wishes can continue the process and establish other lengths , but the goal is still to receive all broadcast TV in very good quality.

Limitations

So that colleagues on the „wire“ are not left with the doubt that I have established the propagation of radio waves and the ways of their reception, I am obliged to introduce the following restrictive postulates:</p >

1. Nothing new under the sun after 1888-1900, in terms of research material. See Hertz, Popov, Marconi. Well, yes, they did not deal with microwaves…

2. I have „laid down“ the ideologies and realizations of wiser people than me, who worked and are working within a radius of 3 kilometers from the wheel on the boulevard that leads to Plovdiv and Burgas (why is it the Tsarigradskoe highway and not the California highway? With a sufficiently good reinforcement it can be used there too, yes! Some heroes even try it as an option from time to time. Well, they make sacrifices… but these are the risks of life inclusion.

3. What you will read further about the antenna and its realization can be said and written by 1/8 of the Bulgarian population (In my wife’s opinion!).

For enthusiasts who don’t want to rotate room antennas and change arm lengths or unfurl masts like sailboats with corresponding massive „real“ antennas, try Turkish „satellites“ ” etc. gravity irons, I offer the following recipe (as well as an opportunity to shine in front of the fairies, whatever that means!). We start with a preparatory part and procurement of materials for the antenna.

So, sit down with a friend or neighbor for a „brief production meeting“ and drink a beer from an aluminum can. We need two boxes. If the person standing opposite also needs an antenna, just repeat the operation. The appetizer – according to the season. So far we are only talking about preparatory operations, so beer can be overdone. Leave the work for tomorrow!

The philosophy of the antenna is as follows: dipole 2 x λ/4 volume vibrator with approximate resonance frequency f res. 620-630 MHz, the band of which is wide enough and covers frequencies from 500 to 750 MHz. The bulk vibrator has better gain than the thin wire, but it’s still multiple vibrators. Those who have touched such material know or must have experienced the strong frequency dependence of directional antennas of relatively thin material (λ/d element. >300 and up). So this will basically be a decimeter antenna. And for the metro Channel 1 (for the different broadcast areas 210-220 MHz) – answer below!

Antenna behavior in different regions of the country:

1. In the Ovcha Kupel area (Sofia) the following programs are watched from the Kopitoto tower with very good to excellent quality of perception – Channel 1, BTV, Nova, 7 dni, GTV, CTN and Euro News, which, however, is not broadcast 24 hours hours. Pernicans can benefit from exactly the same scheme.

2. If you are „dead end“ and only the roof can see the Hoof – experience has shown that with a 35-meter (hey, that’s from the first to the roof of the ninth floor) 75Ω coaxial line and a TV „FUNAI“ 14″, year of manufacture 1995 (as my son), did a great job with the reception. The attempt was made in the Mladost region.

3. From the Ovcha kupel region with a TV tuned to the broadcasting frequencies from Mount Botev (the distance is about 140 km) the following was received – BTV with excellent quality, and Ani Salic from Mityo Krika can easily be distinguished on the first program. Just kidding, of course, the quality is only slightly worse, and if you wear dark glasses, you might not notice a difference at all!

4. From the area of ​​the village of Gorni Dabnik (83 km from Botev peak) on the frequencies broadcast from the top, the first and second programs are excellent. On top of that, the antenna caught Nova TV (up to that point it was not received at all), which broadcasts with 10 W from the town of Dolni Dabnik, about 10 km from the village and the route is relatively closed. On top of that, the natural curvature of the Earth at 10 km is 2 meters overhang. Someone will say – come on, how much is two meters?! And her from two meters away… …admire a chick, right?! Two meters is two meters.

Table 1. Elevations between two points on the surface of the globe to help people only by craft (to make and operate the antenna not relevant).

In conclusion of this part, it can be said that what is proposed can replace the big rotten antennas. With relative or good visibility of the transmitter, the 2λ elevation above the ground (3 meters at least) can be neglected and the antenna stuck in a pot in the room. Otherwise, it can be carried out as an external one, but it must be wrapped with one or two plastic bags, tightened around the stick under the arms of the antenna and cut off the excess part of the bag. Then it takes the form of a small compact package and acquires a completely alien appearance. The purpose of the operation is to protect the coaxial line from running and not to see snowfall even in the middle of summer.

The beer has already been tested

Beer is the test, right? Then let’s go step by step to implementation. Now you can pour yourself a brandy, because peace of mind is necessary!

Necessary materials

Materials needed for crafting at the time of sitting:

• 2 pcs. already empty beer cans;
• 2 pcs. screws 15 mm hex with corresponding nuts and 4 pcs. washers for them;
• a chamois stick with a section of 15/15 or 20/20 mm or a combination of the dimensions, the length is up to you;
• a device or an invented way to drill the bottoms of the boxes with Ø 6-6.5 mm and the stick with Ø 5-5.5 mm;
• device for cutting the thin film of the boxes;
• a short sharp inflexible blade for digging the feeder a little into the stick – as you wish.

Crafting

1. The empty boxes are sized at a height of 90 mm from the base on which they stand (or sit). The easiest way to do this is to cut a strip of paper of this width to wrap around the box and outline. Base – again the table. The cutting can be done with a thin sharp knife or even better with your wife’s fabric scissors (it’s nice that she can’t see it). The cut should be made about 0.5-1 cm above this 9 cm, so that you can use pliers or tweezers to bend the part to size and get a double edge (see the photo). You may not do this procedure and cut directly to 90mm, but the chance of cutting yourself badly between your fingers is high (element of tripping and personal experience!).

2. You drill the bottom of the already cut box with Ø 6-6.5 mm (preferably with a tendency towards the center) and insert the screw with a folded washer from the inside. On the thread protruding from the bottom, you put a washer and a nut, meanwhile supporting the screw from below with the screwdriver. You tighten brutally, because then this screw will also cut the hole in the stick.

3. You drill the stick (not lengthwise!) with Ø 5-5.5mm in such a place where you decided to screw the already made arms of the antenna. You take one shoulder and cut the punched hole on both sides. If you drilled with Ø 5.5 mm it will be looser, but the material of the feeder compacts it. No worries!

4. If you dig a little in the stick as a bed for the feeder, for the line and braid, fasten the feeder to the stick with tape or another tape – the situation becomes even better.

5. Insert some of the stripped braid and wire (about 3-4mm) into the cut holes on the stick and screw the antenna arms. 

6. If you want, you can also use double-folded household foil (from your wife’s) to close the large openings of the boxes by attaching it with tape or something else sticky. The antenna works a little better. If you wish, you can cover the finished arms with cabinet foil that imitates wood.

The visual effect is striking.

If your wife boils you while cutting with her scissors, the effect is downright amazing!

7. The antenna can be attached to whatever stakes you want or simply put in place of the old one. If you didn’t have enough beer from the cans and you continued with two-liter bottles, you can use such a bottle for a stand – you remove the cap and stick the stick with the antenna in its place (of course, the bottle is no longer full of beer, but of water – it weighs on the spot).

Exploitation

So what are you waiting for, try it now!

Concluding remarks of the author

Coca-Cola and Fanta cans have the same diameter, but it is not recommended to make them from such material. Don’t be fooled! Until now, I have never seen a wedding, baptism or graduation party done with non-alcoholic. If you’re not allowed beer, however, due to some visible curvature of the silhouette or other medical prohibitions, try a can of Fanta or another lemonade. The effect is certainly not the same.

Men know why!

Материалът About friends and beer or … how to make an antenna for all over the air TV е публикуван за пръв път на Галя и Тони - Галанто.