How to test a 9 1 unun. Please visit my web site at: rflinear .

How to test a 9 1 unun. Simple and inexpensive to build the 9:1 end fed long wire antenna is a good antenna for both portable and home use. These tuners can tune a range from 25 to 800 ohms. Review the basics, key parameters, different types and common applications of these critical building blocks for any circuit utilizing both single-ended and balanced architectures. Reviews For: Balun Design 9:1 for long wires antennas Category: Antenna parts, accessories, incl. My experience is a coax length of 1/4 wavelength of the lowest band is helpful in some setups. This antenna, like all antennas, has it advantages and disadvantage. Im using 1 capacitor value 100pf@20kv. Can i stack 4 or 5 Feb 11, 2022 · ICOM IC-705 Endfed Antenna Tests - Unun 49. s. The primary to secondary winding ratio is 1 to 7, thereby providing the 50-ohm to 3,200-ohm match. I show you how to build a non resonant random wire antenna with a 9:1 transformer. 👉Support TheSmokinApe Channel on Patreon Here: / thesmokinape Links to products in the video An End-Fed 160-10m Long Wire Antenna with a QRO 9:1 Un-un and 1:1 RF Choke Balun So you’ve decided to homebrew an end-fed ‘ Multi-band Sloper ‘ antenna that will get you on the air from 160-10m. 905 4. The way a 9:1 UNUN works is by transforming the impedance at the end of the antenna wire from 450 ohms to 50 ohms, 50 ohms being the required impedance your transceiver requires. That’s a very popular and common antenna that consists of resonant half wave of wire for your […] I have just built a 9:1 unun to cover 40 - 10 meters. Aug 12, 2022 · Selecting the best toroid material or "mix" for baluns and ununs. Sep 3, 2016 · I am trying to build an end-fed 160m antenna. 7K subscribers 315K views 6 years ago #antenna #homemade #endfed Apr 4, 2020 · What is the difference in performance or something else… with the 5:1 UNUNs with copper pipes Like the one attached and other designs like X turns around a FT240/FT140 etc… for example? (like popular 9:1, 4:1 etc) Im talking about the general design not the ratio (5:1) difference. Consider rebuilding it with a larger gauge magnet wire. The gain (loss) reading in negative dB gives us the total signal loss through the windings. Figure 1 Typical 9:1 Apr 12, 2025 · To check the efficacy of 49:1 unun or impedance transformer, we need to connect the 50 ohms side to the S11 port of the NanoVNA. Jul 20, 2021 · 1) More primary turns and primary inductance improve the transformer efficiency and low end performance. How to choose feed line chokes, line isolators, baluns, or ununs for coax fed dipoles, verticals, hex beams, slopers, loops, windom, OCF, G5RV, ladder line, and yagi antennas Overall Objective: Minimize common mode current (Radio Frequency Interference or RFI) causing feed line radiation on transmission, and rfi generated broadband “noise” on reception. Please note that I will not be describing the construction of the antenna wire radiator here. I was the lucky winner of a end fed half wave (EFHW) antenna The continuity test is DC, but when you start putting radio-frequency AC through it, the reactance (inductance) of the wound toroid presents itself =] { {Series inductors are low-pass filters. Step 5: Wind the ~49:1 unun toroidal transformer. 3) Total losses are approximately independent of core volume. UNUN 9:1 VOLTAGE VERSION 3 9:1 voltage unun using a FT140-43 ferrite core (0. Regarding wires for the turns, some use enameled copper wire, some 3-colour for like This is part 1 of a 4 part video that discussed how to build and test a Multiband Long Wire Antenna, a 9:1 Unun, a 1:1 RF choke, and an Antenna Tuner. 9:1 down to less than 1. Not sure about 4:1. Some antennas are not close to 50 ohms, and a transformer balun with a ratio besides 1:1 may help bring it closer. Note: A better choice for the toroid core would be a type 43 core, which would work better at HF frequencies. I was hoping to see a much flatter swr over the HF spectrum with 450ohm resistor connected in place of the antenna (vna is showing 3. Try making a 64:1 unun (with 24:3 turns) and compare it to this one. You will also need a half-wavelength length of wire (14 or 12 gauge typically) in order to construct an antenna radiator for whichever ham band you choose. If the input is 100 W into 50 Ω, then since W=V²/R, the input voltage is √ (100*50) = 71 V rms. Materials Needed In this video we will a test a 9:1 UNUN at both the 50 ohm coaxial feedline point and the 450 Ohm antenna termination point with a NanoVNA. 2 days ago · Antenna Balun and Unun Home-made antenna baluns projects Balun Construction. The purpose of the 9:1 transformer (unun, for an end fed) is to do the bulk of the impedance match, then the tuner trims the rest of the way. Step 1: Install radiating wire and counterpoise stubs. And you can feed it with coax from your shack. This p In this video, we take a look at some 4:1 UnUn's I made for an upcoming antenna project. A ground rod from the braid side of the feedline at the transformer is a good best practice. Here are some of John's comments: Simple and inexpensive to build the 9:1 end fed long wire antenna is a good antenna for both portable and home use. The unun, therefore, matches it down between 1800 ÷ 49 = 37 ohms and 5000 ÷ 49 = 102 ohms. My tower is 38' tall and I've strung a wire in an "L" shape from the base to the far corner of my half acre. An Amidon FT-240- 43 core is used and sells for $8 at Amidon www. Radio propagatio Related articles at Balun Test Sleeve Balun Common Mode Noise Longwires, Verticals, and Baluns Transmitting baluns 1:1 50Ω Choke Balun – Built with coax, to keep the impedance at 50Ω for feeding a coax fed half wave dipole. Cut longer antenna elements and give them a try. 1 - Balun 9. The 132-foot half-wave radiating element presents about an 1800 ohm (at 10 meters) to 5000 ohm (at 80 meters) impedance to an end-fed feed point. 9:1 Magnetic Longwire Balun / Unun Completed 9:1 UnUn These are sometimes known as a Magnetic Longwire Balun. 9K views 6 years ago 9:1 unun, some spare scrap wire and an old fibreglass pole. I included the tools I The "9:1 UNUN" are for random length wire antennas fed at the end. Uncoil the magnet wire. Typical end-fed antennas are supposed to work on multiple ham bands, so the transformers must be broadband. It has a constant impedance transformation ratio of 49:1 from 3. It is placed at the connection of the coax coming from the radio (50 ohm) and connected to the end of the ladder line (450 ohm) as 9 x 50 = 450. General hints for investigating problems like this: Check your VNA calibration. Making the impedances in the ham bands possibly in the 300-600 ohm range (not a mult of 1/2 wave). I just fling the main element over a tree limb, and tie the end of the counterpoise to a bush or something 180 degrees away from the main element to keep it about a foot or so off the ground. The toroid was a FT140-43, 11 quadrifilar wound, one winding was the secondary and the three all in series the secondary going to each leg of the OCFD. Before I get into the nitty-gritty details, let me first make a distinction between end-fed half-wave antennas, such as the ones sold by LNR Precision and end-fed wires that use some kind of tuning to achieve a 50 Ω output impedance. RANDOM WIRE ANTENNA with 9:1 UnUn home made (part 1) OM0ET 57. DX with such a simple set up makes this hobby so great! Connect with my channel by subscribing an 4 An end fed, 1/2 wavelength antenna will have a relatively high impedance of 5k ohms or more. One popular UnUn and Balun handbook shows a lack of understanding of how to analyze, measure, and test baluns! It actually suggests power is evenly divided between the two choke baluns making up a 4:1 current balun. Its really an impedance transformer (9:1) to feed a high impedance, end fed (unbalanced) random wire which is likely to be a few hundred ohms, and transform it into something closer to a 50Ω (unbalanced) coaxial input, hence UnUn. Ununs are essential when designing compact RF systems, like those found in handheld devices or IoT applications, where the antenna is directly integrated onto the PCB. End-fed, half-wave antennas (EFHWs) are a half-wavelength long and are resonant Nov 18, 2024 · What is a 49:1 Unun? A 49:1 unun (unbalanced to unbalanced transformer) is designed to match the high impedance of an EFHW antenna (typically around 2,450 ohms to 5,000 ohms) to the standard 50-ohm impedance of most transceivers. If this winter ever ends and the glaciers retreat from the local parks, the new improved CLEFHW will be getting a good workout this summer. Transmitting baluns Occasionally errors are made regarding core selection and this especially includes baluns, where some very strange ideas surface. 00. 1 Comparison HAMTech RADIO SCANNER M0FXB CB DRONE HOBBY Diary 41. 👍 *Support B May 5, 2025 · UNUN 9:1 VOLTAGE VERSION 2 9:1 voltage unun using a L15 ferrite core (1. Step 4: Wind the 9:1 unun toroidal transformer. This antenna has been made popular by the Emergency Amateur Radio Club of Hawaii (EARCHI). My antenna length is 41' and my counterpoise is 31'. Great answer, thank you. 5 38 42 My antenna wire is 35 feet long and 30 feet above the ground and its orientation is horizontal, (perpendicular to the ground!) Building the 9:1 UnUn was fun and I was eager to have a multi-band antenna! This antenna got a lot of bad press among the ‘Antenna Guru There are common mis-conceptions about the jobs that UN-Un's, Bal-Un's and chokes do with regard to amateur radio end fed half wave, random wire and di-pole antennas. Generally the 9:1 has far more loss as the transformer/core takes on heat to make the non-resonant antenna be of any use across wide bandwidths and are often deaf across some range of frequencies because Mar 21, 2022 · To get such a high SWR something must be badly wrong with the balun or the test setup, it's not just the spacing of turns or the length of your crocodile clips. 3 20 3 24. Apr 4, 2025 · Im building a 49:1 unun using 14 gauge copper magnet wire. If changing the number of turns on one (or more) winding changes the the voltage, it is a voltage balun. When it goes wrong, it can give plausible but strange results. 8 - 30MHz). All should have ~0 ohms resistance between them. 062 2. 5 - 60MHz). And use a 1:1 between the antenna and the radio/tuner to prevent common mode current on the coax. In the next video I will test them in a real conditions with the antenna wire, rope and Sep 24, 2022 · That should give you a rough idea what impedance matching ratio your balun is wound for. An Unun with a 1:1 impedance ratio ensures that both the PCB antenna and the coaxial transmission line are matched, reducing signal reflections and ensuring maximum energy transfer. Aug 18, 2022 · Check the unun temperature after transmitting. To read more about the EF antennas, please google and you find a lot of info. This is a followup video to #344 where I assembled the 49:1 UNUN kit from HF-Kits / ARRL. The end-fed random wire antenna has a 9:1 UNUN designed for use with radios that have an antenna tuner. Sep 18, 2019 · However, when comparing the two in reception there is little difference in actual results between version one and two. 430 2. Jan 28, 2020 · Testing 9:1 UnUn with 470 ohm resistor in output side using nanovna. Presumably the ferrite toroid works b Nick M0NTV talks about building and testing your own 9:1 UnUn to connect an end-fed random wire antenna to a transceiver. This build is a 4,9,16 to 1 on a sin We test for the BEST capacitor in the 49:1 UnUn / balun matching transformer for the 40-10m End Fed Half Wave EFHW ham radio antenna. Mar 16, 2020 · Checking 1:49 UnUn with nanovna#applications May 5, 2025 · UNUN 9:1 VOLTAGE VERSION 2 9:1 voltage unun using a L15 ferrite core (1. Please take a look at the nanovna results. 8 - 30MHz) was carried out by testing the impedance that could be seen from transceiver side of the unun to a resistive load applied to the antenna side of the unun using an antenna analyser. Step 7: Test the matching unit. Jun 17, 2016 · After buying a couple of 9:1 UnUn's, I decided to try to make my own. Balun = unbalanced coax to balanced antenna Unun = unbalanced coax to unbalanced antenna But if I'm understanding correctly a 9:1 balun and a 9:1 unun differ only in what's connected to them, ya? The types of antennas offer thr shelf 9:1 baluns claim to be good for are the same kind of antennas that online sources say you need an unun for This video is about How to home made the Mini 9:1 or Mini 49:1 UNUN transformers (designed by me OM0ET). I plan on using this on as a 40-10 EFHW. Mar 27, 2024 · BACK-BACK 49:1 UNUNS - RIGOROUS MEASUREMENTS1 - 20 of 20 1 One popular UnUn and Balun handbook shows a lack of understanding of how to analyze, measure, and test baluns! It actually suggests power is evenly divided between the two choke baluns making up a 4:1 current balun. Requiring a unun to feed a long wire antenna ideally without a tuner a 9:1 voltage unun design using a T200-2 Toroid core was selected. Oct 24, 2020 · In the search for the “Wonder Antenna” that is small, portable and easy to setup, I’ve decided to build an Endfed antenna using a 9:1 match. (10) Test the SWR with an antenna analyzer, preferably one with a graphing function like the RigExpert Zoom models or the NanoVNA. I did plan on doing the 1:1 choke as well, but May 23, 2023 · 49:1 unun test results1 - 13 of 13 1 Oct 12, 2020 · I have a 9:1 unun I've used in the past; main element is about 53 feet long and the counterpoise about 14 feet long. So I bought it and adventured into my first 9:1 UnUn transformer build. Connect a non inductive 450 ohm resistor from the antenna side of the balun to ground side of the input then test with an antenna analyzer, VSWR should be very low over the rated frequency range and that will tell you if the balun is ok. Dec 31, 2011 · Before you add a resistor in between i suggest you to test with your antenna analyzer as is. Measuring a balun with a DC ohmmeter is tough because of the low resistance of the windings. be/h0sn Simple bench test for the impedance transformation of 49:1 Unun used for End Fed Half Wave (EFHW) dipole antennas which are quite popular for ham radio field operations. Voltage Baluns 50 ohm 1:1 Balun – A simple 50Ω 1:1 voltage balun made from a ferrite core. toroid, balun, unun, 9:1Gan Uesli Starling2023, Gan Uesli Starling Testing homebrew units built from scratch. amidoncorp. As you can see the vswr trace is not that great (also included smith chart. One rather odd but somewhat popular idea is that adding a mixture of core types will allow both high power operation and high choking impedance in baluns by slowly reducing current Aug 12, 2013 · 21. With the counterpoise off, 10 and 12 got better, but the swr for 15, 17, 20, and 40 meters, remained too high Oct 24, 2018 · It's an OCFD, 45ft one end and 15ft the other, a homebrew 9:1 unun at the junction and a braid breaker in the same container. You can find this unun ov Apr 14, 2002 · On 80 meters, the 9:1 unun shows about a 3:1 SWR, on 40 meters, it's right at 2:1 SWR, and it flattens out at 20 meters and stays under 2:1 SWR through most of 10 meters. You may be quite familiar with the end fed half wave antenna. Because this discussion focuses on the end-fed an-tenna, let’s examine how to build a 9:1 unun for it, then explain the modification necessary for a 9:1 balun for a balanced target such as ladder-line. pcbway. I have a 9:1 unun, 84ft wire, 17in counterpoise under the 84ft wire, and a 50ft coax running to my Icom 7300. Aug 18, 2022 · (9) Attach 25 or more feet of 50-ohm coaxial cable to the unun and hoist both ends around 15 feet or more in the air. I was located in north-east part of Slovakia about 350m a. In short, I am very impressed with how easy this was to build and how effectively it matches the 450 Ohm impedance found at the end of a proper length random wire Don't run away! Sorry for the 15 second delay before the video starts. Note: The standard build for the 4:1 unun has the counterpoise wire exit the top of the matching unit. Welcome to Reddit's own amateur (ham) radio club. This 4:1 UNUN can be added to any 43-foot antenna system. This matching is crucial for efficient power transfer and minimizing signal loss. I bought a combo 4:1 and 9:1 balun (unun?) made for long wires but I can't seem to find the correct length for the long wire. Possibly move the unun “guts” into a smaller/better box. Bottom counterpoise. Here I show finalizing the antenna, getting it in the air, and running an SWR sweep on it. 0 Normal 0 21 false false false EN-GB JA X-NONE 49:1 Unun This is a unun ( unbalanced to unbalanced ) transmission line transformer designed to match 2450Ω to 50Ω. 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. Show step by step how to build several different variations and how to measure and compare their insertion losses and efficiency. 73 de Tim Disclaimer: These are projects that I build for myself and don't mind sharing with like-minded hobbyists. The unun consists of 19 bifilar turns of #24 solid hookup wire on a T130-2 toroid. 2 41 75 28. This video will show you how to set up a NanoVNA for testing baluns, chokes, filters, antenna switches and more. 1K subscribers 110 Nov 4, 2021 · This implies a 49:1 impedance transformation from 50Ω, so a turns ratio of 7:1 is required for the transformer. #nanovna_webapp The 1:1 balun (common-mode choke) goes between coax and the 9:1, regardless of type. Building the 1:1 Balun and 49:1 Transformer Corrected tool list. It’s a good idea to test the matching unit before installing the final heat shrink. For the random wire you need to look online for certain lengths of wire to avoid otherwise it will not work properly, so it's not technically random. 5:1. All topics relating to the hobby are welcome here, from purchasing and building equipment, to operating techniques and Feb 21, 2020 · 9:1 voltage unun using a L15 ferrite core 9:1 Voltage Unun - FT240-61 9:1 voltage unun using a T-200-2 powdered iron toroid core What do you think regarding power losses and materials? Which toroid should I use? (I already have the *-61 and the *-2). The most accurate way would be to connect an antenna analyzer across the coax terminals and a 200 ohm resistor across the antenna terminals. Other side which involves the antenna terminal and the ground should be connected to a 2500 ohms resistor to simulate the high impedance of the EFHW. 0 0 1 212 1171 Com One LTD 9 2 1381 14. The 1:1 impedance transformation is achieved by making the impedance of each winding the same. Note: For the 20w kit, nest the two toroids concentrically, and then follow these instructions treating the two toroids as if they are one. Check for DC continuity between the counterpoise (if you installed one), the antenna wire, the BNC ground, and the BNC center pin. Nov 17, 2024 · A 9:1 unun (unbalanced to unbalanced transformer) is a useful device for matching high impedance antennas, such as end-fed wires, to a standard 50-ohm coaxial feed line. All other instructions are the same. What I've built is a 200-2 toroid with 17 bifilar turns. This made me more curious than ever of course wanting to get to the bottom of this differing SWR led me down the road of once again getting out the magnet wire and ferrite cores. 560 2. At worst case, 102 ohms ÷ 50 ohms = 2. 👍 Support BudgetHamRadio channel - https://buymeacoffee. ZERO Antenn Oct 11, 2024 · Building the 9:1 antenna with common mode choke. If you prefer to have the counterpoise wire exit the top of the unit, take a look at Step 7 in the 4:1 unun build instructions. baluns, hardware, etc. com -~- How to make a 9 to 1 autotransformer (UnUn) In this video we make a 9:1 autotransformer, also called an UnUn. Improved installation suggestions for #8 screws. To be Hombrew 9:1 balun and unun. When used with an auto-tuner, the un-un turns a simple piece of wire and a counterpoise wire or radials into a multi-band antenna. Jan 18, 2021 · This video is about testing the SWR of the antenna without a tuner in order to find out what we'll be expecting our Tuner to match. Cut the length of Poly Stealth wire roughly in half. Apr 12, 2025 · Simple bench test for the impedance transformation of 49:1 Unun used for End Fed Half Wave (EFHW) dipole antennas which are quite popular for ham radio Step by step build instructions for a 49:1 UnUn / balun for your End Fed Half Wave EFHW HF antenna. Jul 9, 2020 · Baluns and ununs are as essential in RF and microwave signal chains as they are confusing to engineers working with them. I used mine to build a 4:1 unun for portable use in a Rybakov configuration. 85K subscribers Subscribed 24 1. net I have now, at long last, finally gotten around to homebrewing a balun and unun. Hello all! I've created my first 9:1 unun and tested it by using 450ohm resisters across the antenna out and the ground. Mar 15, 2023 · When I was in the USA a few years back I brought some high-spec, commercially produced 1:1, 2:1, and 4:1 baluns, and a 9:1 unun made by DX Engineering. When the 9:1 is a balun, then it goes without saying that antenna wires will be two, both equal length (or maybe a loop). With a reasonably good ATU in the shack, you’ll achieve this and it won’t cost an arm and leg. You can find plans for winding the unun here and other places on the Internet. If you don't have anything close to 2500 ohms but you do have another 4. Note: The standard build for the 9:1 unun has the counterpoise wire exit the bottom of the matching unit. Mar 10, 2019 · I was tested my home brew mini 9:1 UnUn with random wire antenna 17,68m long. eMail Subscription Registered users are allowed to subscribe to specific review topics and receive eMail notifications when new reviews are posted. Oct 11, 2024 · A 9:1 balun will transform 50 ohms to 450 ohms over a wide frequency range. May 5, 2025 · With the view to establish a quick and easy multi-band antenna deployment for portable and camping operations a simple long wire antenna with an earth or earth plus counterpoise arrangement with a 9:1 voltage unun is one possible solution. this device matches a 450 Mar 14, 2015 · Then this week, my friend John, KN5L and I were debating the use of ununs and he whipped up a perfectly flat 9:1 unun. Here I show you how you can check if you 49:1 unun is working using a NanoVNA and some resistors. Go to the next step. For about $17, I’m very happy Jan 28, 2019 · How to make a 9:1 unun for portable operations Radio Diógenes 1. I don't see where the OP said that the transformer/unun was 9:1 so I am assuming from the description that it is truly an EFHW with a 49:1 unun. . Fairite cores from mouser with fairite p# 5943003801 and mouser p# 623-5943003801. ( Following this general “look” or design I see a number of commercial antennas. They weren't cheap, but this has proved to be on of my best ever AR purchases. Jan 14, 2025 · The way a 9:1 UNUN works is by transforming the impedance at the end of the antenna wire from 450 ohms to 50 ohms, 50 ohms being the required impedance your transceiver requires. Whether you're a radio enthusiast or just curious about antenna technology, this article provides a straightforward introduction and insightful conclusions on RF Antenna Ununs. It's time to see if the unun from Bangood actually ununs (is that a real word?) like it should, and show you how to test your ununs. In this video, we use a RigExpert AA-30. Install per step 3 in 9:1 unun instructions. I can highly recommend this 9135 - 9:1 Unun, in particular for the “low-band antenna experimenter" ”I've been using this antenna in a sloped configuration for 6 months. 9:1 are commonly used with "random" longwire antennas, 4:1 are used with OCFD and full-wave loops. The antenna wire can be used in numerous configurations, although Jul 29, 2021 · DX Engineering’s patented Maxi-Coreâ High-Power Multi-Band UNUN (DXE-UN-43) allows your non-resonant vertical antennas to perform to their fullest potential, while reducing stress on the equipment. Building a 9:1 UNUN for a random-wire multi-band end-fed antenna using an FT-140-43 toroid instead of the usual T106-2. 9:1 is for non-resonant wire antenna, 49:1 is for resonant wire antenna (think EFHW). Back-to-back unun spectrum analyzer measurements suggest losses in the 1-2 dB range; but high power tests that barely got the toroid warm suggest that the losses Just a short demonstration of testing the first stage of my impedance matching network to bring a 200 Ohm load down to 50 Ohm. The resistor was only to simulate the load of an antenna on the unun. 7k resistor, wire two of them in parallel and you'll get 2350 ohms, which is close enough to give you an idea if the unun is working. In antenna feed lines, the balun is often used to balance a coax cable and a dipole antenna Jan 26, 2014 · A few more comments about this 49:1 autotransformer EFHW design. Just a quick video showing how you can test your EFHW 49:1 UnUn for Impedance Matching / Transformation. So a 9:1, or greater, ratio of balun may reduce the impedance sufficiently to help your tuner get a match and help avoid a voltage flash-over in your tuner. Please visit my web site at: rflinear How to build 49:1 matching transformers. We can then divide by 2 This is part 2 of a 4 part video that discussed how to build and test a multiband long wire antenna, a 9:1 Unun, a 1:1 RF choke, and an antenna tuner. Both tested for power. My coax from the shack is about 22'. Top counterpoise. You can also use an antenna called an End Fed Half Wave (EFHW) that is about 66 feet long and uses a 49:1 Unun. This antenna, like all antennas, has it advantages and Feb 14, 2022 · The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. It looks good to me, but curious if I'm looking at this right. Made my first 9:1 unun yesterday, It is made with 200-2 toroid and 16awg copper wire (enamel insulated - just what I had lying around). Jan 30, 2021 · According to "Tinker John" (W5CYF), this basic 9:1 UnUn is easy to make, inexpensive, and will take only a few hours to build. Otherwise, most DIY baluns/ununs would likely be 1:1, 4:1, 9:1, 49:1, or 64:1, so you could try terminating the ‘balanced’ side with fixed resistors of approximately 50, 200, 450, 2450, and 3200 ohms to see which yields the flattest SWR trace. Jun 11, 2021 · Using a 9:1 Unun is a transformer that can accomplish this task at one end of the line. Nov 17, 2024 · Building a 9:1 unun is a rewarding project that can enhance your amateur radio setup by ensuring efficient transmission and reception. With either antenna try and get it up as high as possible for best effect, but even if it ends up being low it will work great for NVIS around the UK and into Europe, so you'll have fun Step 2: Install counterpoise wire. By following these steps and using the right materials, you can create a reliable unun that will serve you well in your radio communications. Feb 7, 2024 · Yes, use a 9:1 Unun type transformer. A hunk of LMR-400, with a 4 turn air choke at the antenna end, connects it to the radio. com. If you prefer to have the counterpoise wire exit the top of the unit, take a look at Step 3 in the 9:1 unun build instructions. This video takes a broad and Explore their applications, understand the difference between BALUN and UNUN, and get a clear definition of what an Unun is in the context of RF antennas. home: ky8d. A balun can still make over-the-air contacts, even when non-functional as a balun. We will test their impedance transformation capability and test for Check out my Antenna Playlist: • Antenna Playlist Check out my NanoVNA Playlist: • NanoVNA Playlist If you liked this video you can see more like it here: / thesmokinape You can also follow me Apr 29, 2021 · I will also be building a 9:1 UnUn and random wire end fed antenna, and a multi-band HF hex beam sometime in the near future, so please stay tuned for future articles in " Project Corner ". I have had great luck with SSB, FT8, and it will tune on everything except 80m. This article will guide you through the process of making a 9:1 unun, including the materials needed and step-by-step instructions. Lets build a 9:1 Unun… Well you need to start with a toroid of #61 material and get a plastic box to Feb 28, 2025 · I adjusted the turns ratio of my QRP unun to 36:1 and the real world (snow covered driveway) SWR dropped from 1. How does a 3:1 autotransformer give a 9:1 impedance uplift? Schematic wiring of 9:1 Unun The explanation is as follows. These two objects require 9:1 imped-ance transformation, but in different ways. This can only be done by picking an antenna length that presents itself as 450 ohms when connected to the 9:1 UNUN. It shows resonance around 15. This is a brief demonstration on how I test a 9:1 before my deployment. repeat the calibration confirm that the open connector gives a nice small dot on the open The 9:1 unun is about 1 foot from the ground, goes vertical for about 12 feet up, then slopes the rest of the way at about a 20 degree angle, ending up about 6 feet from the ground, attached to a wooden fence. A balun or unun with low SWR over a very wide frequency range might not be a good balun or unun anywhere! As a matter of fact, a balun that isn't even a balun, one that always forces a system into severe common mode problems, can test perfectly on a simple SWR to load or SWR to antenna testing. 5-50mhz). Jul 24, 2022 · Unun Insertion Loss (Efficiency) Testing by Joshua (KO4AWH) A simple “side-by-side’ method can be deployed with the use of a Calibrated NanoVNA to read back “S21 Gain” which is, in this case, signal loss from the output of S11 back into S21 through the identical windings. 9:1 Magnetic Longwire Balun / Unun – A 9:1 impedance transformer for feeding end fed wires. Jan 2, 2018 · From eBay I got a very cheap 9:1 UNUN antenna transformer for EF (End Fed) longwire antennas. In testing the swr with the counterpoise attached, 10 and 12 meters are rather good, but from 15, 17, 20, and 40 meters, the swr was too high. 2 30 30 28. Compared to the 1: 9 transformers based on the MTFT principle (Magnetic Transformer for Transmitting), which are usually incorrectly referred to as "magnetic balun" solutions, there are clear resonance ratios and fewer losses on the coaxial cable, which is better matched. 8-1. 5MHz to 50MHz. To operate on any HF band you need a wide range tuner like the internal antenna tuner of an Elecraft KX2 or KX3 or an external tuner like an LDG AT-100 Pro II or an LDG Z11 Pro II. l. Removed redundant pictures. 04:1 SWR, well within tuner range; and in fact, should be very good without a tuner. I am testing to confirm the 9:1 is wrapped correctly and there are no issues with the wrap itself (or solder May 5, 2025 · The evaluation of the efficiency of the unun over the desired bandwidth (1. May 13, 2020 · Using Antscope 2 to check baluns ?1 - 12 of 12 1 BALUN UNUN 1:49 - 49:1 For End Fed Half-Wave (EFHW) antenna 500W - $29. If the analyzer shows a very low SWR it's a 4:1 ratio. Just follow the directions and it was sim used binocular coresfound that they overheat at 100 wattsok for qrpTesting a new Unun using Binocular Ferrites using a Nano VNAsee also https://youtu. A 4:1 balun (balanced to unbalanced) or UNUN (unbalanced to Time to make another Transformer/UnUn this time for curiosity and perhaps for my holidays ( if there's room in the car). Jan 30, 2018 · Get professional PCBs for low prices from www. You might be able to use a DC meter IF it can measure very low resistances (milliohms) and IF the same wire So although this is a 3 to 1 step-up transformer in terms of Voltage, it is a 9 times step up in terms of impedance. Mar 21, 2024 · I will lengthen the wire to 155 ft, or shorten it to 91 ft, and substitute a Palomar Engineering 9:1 UNUN in place of the 49:1 UNUN. End fed antennas generally need a counterpoise, whether an explicit wire attached to another terminal of their unun, or the shield of the coax leading into the unun, or a totally invisible counterpoise formed by their transceiver system's capacitance to Oct 30, 2023 · In between them is an inexpensive 9:1 unun, purchased on eBay from Nelson Antennas for $40. May 31, 2023 · Can a non resonant antenna be efficient? It sure can. You can even How to build the 9:1 UnUn / balun matching transformer to use with a random wire antenna. Can anyone A half-wave wire presents an impedance of about 2500 ohms at its end, which the 49:1 unun matches to the 50 ohms of the feed line. I'm only going to run about 10-15 Aug 12, 2016 · For the past couple of weeks, I’ve been playing with end-fed wire antennas. }} Sep 15, 2023 · In this video, we take a look at two UnUn's that my buddy made to use for SWL and QRP operations. In this video, we dive deep into the topic of optimizing ham radio antennas by exploring the incredible power of 4:1 baluns and UNUNs. This particular un-un is a 4:1 transformer, which seems to work very well in a variety of antenna configurations. However, there is another issue that may require some planning. I've not hooked it up to the wire yet. My question is can i stack more than 3 cores ?? I see video's using 3 but never more than 3. It seems to work best when the transformer is from ~1m to 2m from the ground. It may also work on 6m as well. Oct 27, 2022 · An EFHW usually has a 49:1 unun; not a 9:1. This video shows step by step how to wind a 9:1 unun. Of course, results will vary depending on the actual load, but with a decent tuner, you'll be able to have fun with this simple impedance transformer with all kinds of random wire antennas. This is particularly important when you have a long line of coax to reduce feedline loss when you have this impedance The 64:1 auto-transformer (UNUN) in this article will do just that by matching the 3,200 ohms input of an end-fed wire to the 50-ohm output of the transceiver. In the second video TechMinds provides a similar video and also shows the enclosure that they will be providing in a premium version. Definitely try 80m. If you have any questions or need further assistance, feel Sep 24, 2021 · Project: 9:1 UnUn Transformer I really enjoy doing homebrew and DIY projects around the shack and I recently found a 9:1 UnUn kit on Amazon for pretty cheap. We would like to show you a description here but the site won’t allow us. It wasn't as hard as I thought it would be. 5mhz. Baluns are devices that are used to balance unbalanced systems, from here the acronym BalUn. Nooelec 9:1 HF Balun Version 2? Aug 13, 2022 · My preference for portable antennas is to avoid exposed components or circuit boards. 👍 Support BudgetHamRad May 21, 2020 · Discussion on methods for measuring balun loss using NanoVNA. 2) Winding capacitance and leakage inductance, especially present as you increase the number of turns, limit the high frequency performance. The 9:1 would be used for a "random" wire that would require a tuner to use on multiple bands. If you are wondering what Amateur Radio is about, it's basically a two way radio service where licensed operators throughout the world experiment and communicate with each other on frequencies reserved for license holders. sybkmikv wwdbyzi ddirt mbonyn hdmli ntlmzfbi laj rffpd lseips fvnxm