49:1 unun wire lengths49:1 unun wire lengths

I only used two screws instead of four. Legal Stuff The matching unit The impedance at the end of a half wave antenna is somewhere between 2000-5000 Ohms. Here is an ARRL For example a 32 foot length is actually a half wave on 20m with an impedance of about 3500 ohms and requires a 50:1 balun. It is not a good choice for working lower bands from a too short wire, that is, if you have cut your wire to a 20m halfwave, it ain't much punkin' for 40m, 80m, or 160m. The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? Part List: endobj We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. Random wire lengths you should and should not use! So for example 80m could range in length from 120 to 133 feet. Enclosure Height: 5.000 in. <> The length of enamelled copper wire per winding for the T-200-2 powdered iron toroid core is determined by length per winding = 50mm per turn plus 250mm tails. For a better experience, please enable JavaScript in your browser before proceeding. 4 0 obj << When you're 1/2w long you're around 2k ohms or more where the balun won't under or over xform; as you approach 3/4w your z is going to drop to where a coax match can be made just by soldering the wire to the center conductor sans balun - more or less the principle of the windom and ocf dipole. Some of these numbers are too close to squeeze in between them. https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. x 4 in. (A t0 B) Fold over 6 to 8 inches and twist it together. 40-10m with a 49:1 Unun. K1S Valentines Are (Almost) Out The Door! program or two to do all the dirty work. 0$Ve Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. Step 1: Drill holes for and install the SO-239 or BNC connector, the stainless steel machine screw antenna connector and the ss machine screw ground connector. 1 X FT240-43 Ferrite Toroid Core 43 Material(Mouser Electronics), 1 X SO-239 UHF PANEL JACK S/CUP SO-239(Mouser Electronics), No. On our next windy free day, AA1F and . Picture Information. 35. 73, To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. /Creator (XnView) In stock . Presented for your consideration by Jack, VE3EED. thank you. Longer wire is always more (Note: I am not satisfied with this part of the project, so I will describe it here briefly. I took a literally random length of 14 gauge house wire and attached a banana plug to be shoved into the antenna port of the tuner. which got me thinking. Figure 2 Schematic of the 9:1 voltage unun . If you want a single band portable antenna you can mount pretty much however, look up this design. Lengths for Long-wire Antennas Jack - VE3EED Recommended lengths: 29 - 35.5 - 41 - 58 - 71 - 84 - 107 - 119 - 148 - 203 - 347 - 407 - 423 Not recommended lengths: 16 - 19 - 22 - 26 - 32 - 33 - 38 - 44 - 46 - 48 - 52 - 64 - 65 - 66 - 76 endobj You are using an out of date browser. The "9:1 UNUN" are for random length wire antennas fed at the end. 3 to31 MHz - up to 1kW intermittent (50% duty cycle). That meant calculating all the way to 32 multiples of a half wave on 10 meters. Ham Hints For those that enjoy the LNR and Hy Endfed antennas, but want to run more power, We have also installed an additionalstud which can be used for a separate counterpoise wire rather than forcing the use of the feedline's coax shield, ttaching a counterpoise wire to the common point of the auto-transformer, provides the antenna radiator something to push against rather than the coax shield. /* Ad banner 160 x 600 */ << The 49:1 unun with 3000 ohms of resistance shows a VSWR under 10:1 from 160M to 15M, and less than 3:1 from 80M to 20M. I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. This type of antenna is very easy to install because there is no need . SWR will vary based on topography, wire orientation and use of ground or counterpoise. The Short Answer Would Be That an UnUn Is a "UN balanced to UN balanced" matching transformer. Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. //-->, The "Best" Random Wire Antenna Lengths . Work all bands from 80 through 10 on it. A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. AndWhat Is It Used For In Antennas? This will be for an eyehook in order to provide strain relief for the radiator wire. Kj8~q7c? So for 80 meters (say 3.525 MHz) this gives you about 133' of wire. stream I have not done this yet. Drill another hole in the same side as the antenna radiator wire mount hole. /Type /XObject 1 0 obj It's an efficient way to get all the multiples I used 2000 and 1000 ohm resistors in series connected to the proper unun wires with alligator clips for a total of 3000 ohms. So you have the freq range of interest and the total length of the wire, figuring out wich balun will be a better match for 50ohm coax should be easy. 4 x 4 x 2 electrical junction box (available at big box hardware stores), One PVC DWV Test Cap (available at big box hardware stores in plumbing). 9 0 obj Box cutter (for scraping enamel off of wire ends), (Helpful) Step drill bit for SO-239 connector, Paracord (for simulating and measuring lengths of windings on toroid), Antenna analyzer for HF frequencies (I use the RigExpert Zoom AA-55), Resistor(s) totaling about 3000 ohms (I used 1K and 2K ohm resistors in series). For example, You have to stay away from a half wavelength on any frequency. Here are the final numbers (in my opinion) in green below that would be good for a long-wire antenna: (You may want to make a note of them), REVISED: 29 35.5 41 58 71 84 107 119 148 203 347 407 423, REVISION NOTE: We had a note from James, KB5YN, pointing out that one of my so-called GOOD numbers was 220 feet. plan to use. The counterpoise wire does not have to be similar in length to the main radiator wire and just a short wire is all that is needed, about 0.05 . Several ways exist to bring the wire's high impedance feedpoint closer to the desired 50 ohms, including use of a 49:1 or 64:1 unun, which eliminates the need . Building on the original 1:1 design by Dr. Jerry Sevick, this balun has two (2) cores in a stacked Model 49131 - 49:1 - 80-10m EFHW - Up to 1kW, Decrease Quantity of Model 49131 - 49:1 - 80-10m EFHW - Up to 1kW, Increase Quantity of Model 49131 - 49:1 - 80-10m EFHW - Up to 1kW. Here Is a 250 Watt Home-Brew That I Made In about an Hour. Antenna Safety! This is the latest and greatest transformer design for End Fed Half Wave (EFHW) antennas. Cut a 4 foot length of AWG #18 enameled wire. Just a note, if you make one of these yourself, you need to twist together the first two wraps of the 14 winding wire with both wraps of the two winding wire. Each vertical blue line represents an amateur radio band. An excellent way to attach a long wire antenna to the Ham It Up, this 1:9 balun has an SMA output port and high-quality spring-type terminal block input for your coax. Wait a few minutes for glue to set. This is to avoid the antenna radiator from acting like a resistor, and thus instead of radiating radiofrequency energy produced by the transmitter, sending it back down the coax toward the transmitter. hbbd```b``^ "Cs;D2 I*`0D;+EVUHy`qml0{YVw`b0i DvkAh |"w I2% ?W%@Fg`` 6 Use only the white gaps for your antenna lengths, and if Let's have a look at a few details on how to build a 49:1 impedance . Ham Radio Videos! Re: 9:1 or 49:1 unun for end-fed long/random wire? Yes, with the recent surge in popularity of the end-fed half-wave antenna, the 49:1 balun has also become the defacto ratio for use with them. Attaching a counterpoise wire to the common point of the auto-transformer provides the antenna radiator something to push against rather than the coax shield. 25 0 obj <> endobj The 49:1 impedance transformer will help you bring down the high impedance of your resonant EFHW antenna to almost 50 Ohm. % The goal of the impedance transformer is match the 50 ohm impedance of the feedline (coaxial cable) with the potential 3000 to 4000 ohm impedance expected from an end-fed half wave antenna wire radiator. Midi Music Using a 49:1 transformer shoot for the best 50 match @ appx 2450 load over your working frequency bands. In the first year using this unun with a random length endfed wire (Aluminum Elec fence wire at that) I managed to confirm WAS via LoTW on 10m, 15, 17, 20, 30, 40, 80. . "Can you please recommend schematics that are designed to tune setups like these? PVC Junction Box(Home Depot), 1 x 1/2 in. You can add your own wire or get the complete product from this link EFLW-3K antennas. gnuplot 27.00 (27.00/Unit) Free Postage. Cannon". If you want all the bands from Winding 1:64 Matching Auto Transformer on the FT240-43 core. /Count 1 endobj So those are the numbers above thatwe have to stay as far away from as possible when building a long-wire antenna. 6 0 obj It is important to use a counterpoise. <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> q http://udel.edu/~mm/ham/randomWire/. In addition to multiples, I have used the 49.2 ft (15 Meter) length of wire on vacation with both automatic tuners and an MFJ Model 16010 tuner with good results for 40, 20, 17, and 15 Meter operation. Product Reviews google_ad_client = "ca-pub-9377297764300878"; SEARCH presents an extremely high impedance to the tu endobj (Also note that here may be instances where the suggested lengths may not work exactly due to the many variables in the surroundings of the antenna, wire length variances, your tuner, it's height above ground, it's construction, etc. VSWR analysis of the antenna in the field showed that VSWRs between 3-5.5 from 40M to 10M. document.getElementById("copyright_year").innerHTML = new Date().getFullYear(); An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). uR5I5z G^u2`j[}+sy9 In another life, I could have been a telephone engineer. Suggested wire lengths for 1-61 MHz operation (measured from Bullet wire point): Bands Covered (meters) Wire Length (feet) Minimum Coax Length (feet) 40-30-20-15. JC[ d8O[UKKQ{yZ{G 'Upno_*~8uo a@G`' zxUHXW&`}mEp`?i0 oE:N0-/t"t.-? An end fed antenna consists of a wire fed on its end, the length of that wire is not resonant with any frequency or frequencies you will be using it on. 74 0 obj <>stream A 9:1 matches 50 ohms to 450 ohms and that turns out to be an ok compromise for feeding 50-100ft of wire for general purpose SW receive. endobj Tools In other /Length 10 0 R As an example, a 28-31 foot wire will typically allow 40 thru 10 meter coverage and a 43-50 foot wire will provide access to 80 thru 10 meters. The graph below shows lengths to avoid for different collections of bands. 8 0 obj Downward impedance transformation by factor of 49. Many hams have tried till they are blue in the face to install the random wire antenna that works on most; if not all of the HF bands with terrible results. UNUN 9:1 or 4:1- 3kW ICAS This is is dual 9:1 and 4:1 UNUN used for popular "non-resonant" length END FED wire antennas or verticals like 27 or 43 feet. This calculates to 4.2 m or 14 ft for an 80m end-fed. x@ <> The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. Feeling a bit too lazy to calculate that by hand, however, I wrote a There are so many new frequencies to stay away from, that it gets pretty tricky for the longer wires. /Kids [ 4 0 R ] Advertising Info "I received my third balun from Balun Designs this afternoon. 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 50 (unbalanced) coaxial input, hence UnUn. 22.00 + 5.00 Postage. google_ad_slot = "1982258389"; Windings are inserted into Teflon tubes increasingtotal breakdown to 10,000 volts. Gil Gruson 1 Campaign | Comines, France $0 USD 0 backers 0% of $3,450 Flexible Goal Follow Story FAQ Updates 0 Comments 0 Prototype The project team has a working demo, not the final product. ", KiwiSDR Online Radio - 500 ft Northeast Beverage, KiwiSDR Online Radio - 400 ft South Beverage, KiwiSDR Online Radio - 10/11m dipole up 20 meters high. 1 0 obj | The kit includes the parts needed to construct a 49:1 impedance matching network, which will transform the impedance to 50 Ohms, which will suit most transceivers. The First Thing New Hams Often Ask:What Is An UnUn? We have also installed an additionalstud which can be used for a separate counterpoise wire rather than forcing the use of the feedline's coax shield. Note: My (A to B) length was 6 inches. END FED "RANDOM WIRE" HF DIPOLE 9:1 ANTENNA RELACEMENT ELEMENT ONLY $28.99 Save up to 6% when you buy more. The magic lengths to use with the End Fed longwire is 29, 35.5, 41, 58, 71 and 84 feet I use a 29 foot wire with my PackTenna 9:1 balun for 40m-10m and then add a 28 foot length for better coverage on 80m when needed. The QRP End-Fed Half-Wave Antenna 49:1 Transformer Building a great impedance transformer for Ham Radio end-fed wire antennas. 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA The vertical (y-) axis shows the VSWR and the horizontal (x-) axis shows the frequencies. here are values for CW portions of the USA Make sure the beginning few inches of twisted wire is not involved in the winding (i.e., just hanging down from the toroid). A level of 500-600 watts is the maximum with a further reduction onany band measuringabove 3:1. The popular End-Fed Half-Wave (EFHW) Antenna is an easily portable, high-impedance (2,000-4,000 ohm) wire antenna that resonates on its fundamental frequency and all harmonics above. I usually go with a 3.2k transformation wire winding ratio of 8:1 which is a final impedance conversion of 64:1 (50ohm * 64 = 3.2k ohm). That is the 10th multiple of a half wave on 15 meters. Notice from column f that there is no length giving low impendance for , Most matching problems occur when the antenna system This unit is a Balun Designs, in collaboration with Fair Rite products, has developed what we consider to be the best single core 1:1 feedline isolation balun available today. HF & Shortwave endstream 33 ft #18 insulated copper wire (20m half wave), Counterpoise: 1 meter coax (0.05 x wavelength) connected between 64131 and Balun Designs 1115d Isolation /Choking balun, If you would like to use high power up to legal limit with a single end fed wire antenna (not necessarily a half wave) consider using our. Enclosure Depth: 1.250 in. He had heard good things about 'Balun Designs' so he recommended you. /Type /Pages This article details the construction of the transformer. Liquidtight NM 90-Degree Connector(Home Depot). Save program output in file named 'f', and use Just an FYI that I thought you might be interested in. You can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. This article explains why the use of mix 43 for HF applications is almost always a mistake. I connected the free untwisted end of the short wire to the center conductor of my homemade testing jig (see tools list) with an alligator clip. Wire lengths for the 4:1 ratio in models 4130, 4132, 4134, 4932 and 4935. stream The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. var sc_security="1df091cc". The unun was floating at about 15 feet above ground. 32.00. SSTV 59 0 obj <>/Filter/FlateDecode/ID[<81C501BAF3AD19DF6B2122F37F15AF84>]/Index[25 50]/Info 24 0 R/Length 149/Prev 898971/Root 26 0 R/Size 75/Type/XRef/W[1 3 1]>>stream That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . I connected it to a 33 wire running from my balcony, through the trees, and ran WSPR overnight to check things out. Hi guys,not really hfu related,but I tought I might ask here as I have my account. The fewer bands, the fewer high impedance regions to avoid. %PDF-1.5 % This is a 4:1 Current Balun.That means it can match a 200ohm antenna to a 50 feed line. A standard recommendation (see QST, March 1936, p. 32, "An Unorthodox , This is a partial reprint (with permission) of an excellent series of articles published by KV5R A VSWR sweep of the unun after adding a 100pF capacitor shows an SWR <5:1 from 160M to 10M. Multiples are on C and Y &lD30. When you're antenna (or radial) length's an odd multiple of the operating freq, you may not need a balun or even a transmatch. frequencies for your country or favorite modes. Code Practice unavailable, a random wire can save the day, but it is important to Tweak the antenna length if necessary and then maybe adjust the turns ratio again. At multiples of half wavelengths of the SO-239 connectors are silver plated with Teflon insulation. In fact, the 9:1 unun that I built is actually an autotransformer. /CropBox [0 0 748 752] I actually did this first and before the connector was bolted to the box. Thanks for your answer,I will probably go with the 9:1 then. /Title (Wire-Lengths-for-9-1-ununs.pdf) random wire page. Here Is a 250 Watt Home-Brew That I Made In about an Hour. j#f5(fk0?P[polEo5b2-/oVZu1Qo-I6C/M@TbddPc#cdZZ|7+|o{}!F#?Go7ju|?wwgow/c2/W-m~~hn[S29OU}}r7lc]wsw[shS[#qbrrK[7*0,Xv{k+o {=*vo S__O~*=y/zk75O?yjCnXS{`~Ii'c_GxN. random wire should use 423/f. Recommended wire lengths for Unun models 9130, 9132 & 9135 Table shows typical SWR relative to installed wire length. good show chuck, you said ya picked up a 430, did i tell i fried the 0ne i got from you, can anyone point me in the direction of a 2 pill schem for the HG 2879? . This transformer is designed to be used with an end fed half wavelength of wire only. An Unun is used to match an unbalanced line to another unbalanced line. Placing 3000 to 4000 ohms of resistance between the free end of the twisted portion of wires (the gound) and the free end of the long wire (the wire that connects with the antenna radiator after the 14th winding), can simulate adding an antenna radiator wire to the unun impedance transformer. 1 bolt for antenna hook up (with nuts, washers, lock washers, and possibly thumb screw; I used #8 diameter, about an inch or so in length.). answers on D - one setting. These are sometimes known as a Magnetic Longwire Balun. This homebrew 49:1 impedance transformer is the heart of any EFHW antenna you will build, most of the time. transmit frequency the impedance is so high that tuners in most rigs endobj wire lengths less than 1/4 wavelength of the lowest desired frequency I imported my spools from the US, but I have seen them on Ebay in the UK. Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. I use this 8010 EFHW at home, too. 73. JACK, VE3EED Humor This antenna, which works on 10, 15, 20, and 40 meters, has a very high impedance of around 2,500 Ohms. https://www.kb6nu.com/playing-end-fed-wire-antennas-91-ununs/, http://www.hamuniverse.com/randomwireantennalengths.html, https://www.youtube.com/watch?v=sty7RlXQoJI, https://www.youtube.com/watch?v=WwJnXTVUrgI, Quote from: refmo on October 15, 2019, 2036 UTC, Quote from: joczo on October 16, 2019, 0815 UTC, http://www.w3pga.org/Antenna%20Books/Reflections%20III.pdf, http://www.arrl.org/files/file/Technology/tis/info/pdf/7007024.pdf, http://www.tasrt.ca/AntennaTips/AntennaTips.htm, http://www.wb2rcb.com/documents/balunlin.pdf. Modify bands and The ratio doesn't need to be 49:1 2,400 ohm either, other ratios will transform to other impedance. However, the radio didn't tune up very well on 15 meters. You will note that when comparing my results with VE3EED that some of the results are a bit different. Electronics You also Just add or subtract as needed a little at a time toget the best compromise. The bandwidth where SWR was below 2:1 was about one MHz. For instance, to work 40m be sure the antenna is at least 10m or 33' long. installed, it is a compromise antenna but great for portable use because The 49:1, shown in my previous message, is meant for the EFHW that are fed close to or on the half wave (highest impedance) point. endobj So after much frustration..down it comes and you go on to a totally different type of antenna.all that time just wasted inyour opinion..until now! The 30 day return period lapsed before I could get the antenna deployed to test it. /Producer (XnView, http://www.xnview.com) Antenna Design The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. >> are blocked out because an antenna should be at least that long. I connected the free twisted end of the short and long wires (the ground) the chassis wire (ground) of my homemade testing jig with alligator clip. Lowest Band of Operation: 160 meters Highest Band of Operation: 10 meters Additional Information LDG Electronics RU-9:1 Unun
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