Ultimately, this housing works fine, but it is heavy and clunky.). 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. it is easy to pack and easy to install. 2 0 obj 35. <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Ask Elmer Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. endobj It is optimized for 3.5/7/10/14 MHz but will work reasonably well on all amateur bands from 80 meters thru 10 meters with a 135 foot length of wire and a short connection to ground. 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). In theory, my LDG Z100 Plus autotuner should be capable of matching the impedance of this 49:1 transformer with a end-fed half wave length antenna radiator across all amateur HF bands. For a better experience, please enable JavaScript in your browser before proceeding. For example, 40-30-20-17. The length of a half wave antenna is calculated using the following formula: L (ft) = 468 / f (freq in mhz). Use a slide rule! Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. AndWhat Is It Used For In Antennas? The transformer usually used with an end fed wire is a 9:1 transformer. $1YacO5Q}YC\>qZ } 0 (Also note that here may be instances where the suggested lengths may not work exactly due tothe many variablesin the surroundings of the antenna, wire length variances,your tuner, it's height above ground, it's construction,etc. The major point of this message is to tell you that approximately 20 minutes after I connected the balun unit to the antenna, I made contact with a gentleman in Italy-my first European contact!! (QST, Oct 1926, "The Length of the Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. the program as I did, above, for my K1. IMG_2.jpg Step 2: Take the 6 feet of 18 gauge enameled copper wire, measure 11" from one end and fold it back. You can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. We'd really appreciate it! <>>> Hi guys,not really hfu related,but I tought I might ask here as I have my account. 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. While I have not done so yet, I plan on gluing the test cap to the back of the junction box. 2 0 obj 10C) for the 10-80 m bands, or even 6-160 m: 17 ft (5.2 m) of twin-lead and 68 ft (20.7 m) of antenna wire (i.e., standard dimensions). Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. An Unun is used to match an unbalanced line to another unbalanced line. Downward impedance transformation by factor of 49. Multiples are on C and You are using an out of date browser. You have to give up a band or two, like 60m and 6m, as wire to the UnUn "-" connector and then down to ground there it connects with the two other wires but neither the counterpoise nor the two other wires are connected to ground. >> Continue on winding the long wire through the toroid to complete loops 3 through 14 as shown in the schematic below. 73. JACK, VE3EED I used the RigExpert Zoom AA-55 to test VSWR of the 49:1 unun impedance transformer. JavaScript is disabled. I swept the VSWR of the unun and resistors as described from <1 to 55MHz. 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. The 49:1 impedance transformer will help you bring down the high impedance of your resonant EFHW antenna to almost 50 Ohm. Drill a hole in one side for the antenna radiator wire mount (for a #8 bolt in my build). The other is to provide strain relief for the antenna wire). /&KWA7{L=D]g0Z!F9;V{zL[h-D,u(.9rg(RHI{f t*C/?? 74 0 obj <>stream For instance, to work 40m be sure the antenna is at least 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. A couple hours later when I sat down to do some more DXing, I made contact with a gentleman in Slovenia-my second European contact. 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 u?X`f0&/Ri;W0Tn_*TX:ug I'm consistently pleased with the quality and ease of use of Balun Designs products and look forward to my next purchase in the future. /CropBox [0 0 748 752] The WSPR map is so dense it looks like the US and Europe are just big blobs of color. Theme: Newsup by Themeansar. google_ad_height = 600; 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? Turns 1 through 14 are secondary windings (the long wire). Wire lengths for the 4:1 ratio in models 4130, 4132, 4134, 4932 and 4935. endobj End fed 9:1 58ft wire and 17ft counterpose wire touching ground. Enclosure Depth: 1.250 in. endobj An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). Legal Stuff Our newdesign isperfect for matching both long and short length wire antennas for multiband use. Both were on 20 meters at 97 watts, Icom 7300. 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. Designed for use with single wire unbalanced antennas, this new addition is small, compact and perfect for quick portable/emergency installations. Use with other lengths can potentially damage the transformer depending on power level in use. 25 0 obj <> endobj Designed for those who want the maximum isolation and choking across the full HF spectrum. var sc_security="1df091cc". here are values for CW portions of the USA To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. I connected it to a 33 wire running from my balcony, through the trees, and ran WSPR overnight to check things out. NEMA rated 4x marine grade junction box for outdoor installations. Here Is a 250 Watt Home-Brew That I Made In about an Hour. 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! You'll want to have that wire up as high as you can get.. (Center fed is so appealing because you avoid this.). Wire lengths for the 4:1 ratio in models 4932 and 4935. Repeater Basics The unun was floating at about 15 feet above ground. The vertical (y-) axis shows the VSWR and the horizontal (x-) axis shows the frequencies. 8 0 obj endobj REVISED: 16 19 22 26 32 33 38 44 46 48 52 64 65 66 76 78 80 88 92 95 96 99 104 110 112 114 123 128 130 132 133 138 144 152 154 156 160 165 171 176 182 184 190 192 195 198 208 209 220 224 228 230 231 234 240 242 246 247 256 260 264 266 272 276 285 286 288 297 304 308 312 320 322 323 325 330 336 338 342 352 361 363 364 366 368 369 374 380 384 390 396 399 400 414 416 418 429 432 437 440 442 448 455 456 460 462 464 468 475 480 484 494 495 496. The matching unit The impedance at the end of a half wave antenna is somewhere between 2000-5000 Ohms. Care to buy us a beer? Two pieces of 14 gauge enameled wire (e.g., Thermalese), one short piece (about 1 foot in length) and one long piece (about 7 feet in length). 0$Ve (The numbers aboveare a great start, thanks to Jack and Mike! 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. this It's an efficient way to get all the multiples which got me thinking. At multiples of half wavelengths of the So those are the numbers above thatwe have to stay as far away from as possible when building a long-wire antenna. Ham Radio News! The free end of the untwisted portion of the long wire (past the 14th winding) will be secured to this bolt as well on the inside of the box, while the radiator will be secured to it on the outside. 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. About Batteries That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . plan to use. You need to use these lengths and the longer ones . 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. Having the option to switch rapidly between 49:1 and 64:1 should prove to be a really nice feature.. /Count 1 This is a 4:1 Current Balun.That means it can match a 200ohm antenna to a 50 feed line. Lowest Band of Operation: 160 meters Highest Band of Operation: 10 meters Additional Information LDG Electronics RU-9:1 Unun END FED "RANDOM WIRE" HF DIPOLE 9:1 ANTENNA RELACEMENT ELEMENT ONLY $28.99 Save up to 6% when you buy more. Product Reviews The bandwidth where SWR was below 2:1 was about one MHz. They just saved you and I loads of time and frustration. https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. This is considered a random wire end fed antenna, not to be confused with a half wave end fed antenna which uses a 49:1 or 64:1 unun and a wire that is a half wave length. This type of antenna is very easy to install because there is no need . Caution: When used atfull power rating of 1kW, the antenna must have a low SWRon the band selected and be used on a 50% duty cycle. Tools It uses an FT140-43 or FT240-43 toroid in a 49:1 impedance matching unit at the base and a 110 micro Henry (H) coil to act as a loading coil for 80m and a choke to stop higher frequencies using the last 2m of wire. Winding 1:64 Matching Auto Transformer on the FT240-43 core. The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. << There probably should be some holes for ventilation. endobj V#X~[Z?\ZcX:-Y?&Y?IqTnayZ{jTZOub}=UTWu1G>o.,RaT c=W>:sECXTkc=X x 2 in. "Can you please recommend schematics that are designed to tune setups like these? 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. 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. In stock . See the picture below. One is for the top of the box so that it can be hung up. %PDF-1.4 Antenna") is an 84' long end fed and a 17' long counterpoise (6.5' for 20m). x[q;`&z`uAlo#V@;hvOYt, @*Ys~_W_~W_aw_ p[N+}[t-^oLy}xz>7/~c|ZZt75;kN^=>Y+_~|b~"m*tw>xG=x6Qwz|xvz- /Length 6 0 R 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 Model 9135 along with one of the wire lengths shown in the Installation Notes. 1863 1.49 swr 3915 2.50 7200 1.80 14.332 1.29 18.130 1.07 21.300 1.40 24.950 1.30 28.400 1.37 This is a great antenna that is . We hoisted the free end of the antenna wire approximately 30 feet into a tree. Because I'm more visually oriented I then plotted the many overlapping "red zones" and ended up with the page at: 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. 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. x 4 in. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. We recently found some good information about random wire lengths that you should and should not use. , Most matching problems occur when the antenna system Experimenting by slightly changing the wire length (+ or-) is encouraged to provide best overall performance. BUILD INSTRUCTIONS FOR 49:1 UNUN IMPEDEDENCE TRANSFORMER: WX1MAR and I brought the DIY 49:1 unun with a borrowed antenna radiator wire cut for 20M half-wavelength to Ashland State Park K-2417 in Massachusetts for a Parks-on-the-Air (POTA) activation. (Note: I am not satisfied with this part of the project, so I will describe it here briefly. Enclosure Height: 5.000 in. Each vertical blue line represents an amateur radio band. Do what works best! The trick, therefore, is either endobj I've made contact with several folks across North America in my 6 months as an amateur but getting to Europe flipped a switch and I'm afraid this amateur radio thing is going to be addicting. Save program output in file named 'f', and use =======================, More on Random Wire Lengths from Mike, AB3AP (06-29-2012), I was surfing around Hamuniverse.com and found thIs page on random wire antennas: It is used for non-resonant verticals like 43 foot or 33 foot Or Wire antennas like an End-Fed 1/2 Wave Multiple Length Wire Antenna. 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). . hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r . Balun Designs. Figure 2 Schematic of the 9:1 voltage unun . Here Is a 250 Watt Home-Brew That I Made In about an Hour. << When used with the stated Balun Designsis now offering a low power alternative for those who want to use an End Fed Half Wave for portable or temporary installations. Here's a list of recommended lengths of wire to use with a 9:1 unun. all US ham bands. This undesired reflection of RF power back toward the transceiver is identified as a high voltage standing wave ratio (VSWR or SWR). (Originally published February 22, 2021). A so-called random wire antenna is an end fed antenna. . Part List: InJack's own words. Cut the antenna radiator wire (free untwisted end of long wire) of the unun to the correct size, scrape the enamel insulation off of the free end with a box cutter, add a ring terminal, and secure to antenna radiator bolt with washers and lock washers. Kj8~q7c? wire lengths less than 1/4 wavelength of the lowest desired frequency 5 0 obj This transformer converts the impedance at the end . Best SWR was . While these lengths have been shown to work well on many bands, which are easily converted to half wavelengths by the famous 468/f generally I use this 8010 EFHW at home, too. random wire should use 423/f. /Type /Page The Short Answer Would Be That an UnUn Is a UN balanced to UN balancedmatching transformer. installed, it is a compromise antenna but great for portable use because Use with other lengths can potentially damage the transformer depending on power level in use. A 49:1 would match 50 ohms to about 2,450 ohms and a 64:1 matches to 3,200 ohms, typical of a 1/2 wave end fed. Picture Information. Proudly powered by WordPress Free Postage. Jack, VE3EED, hopefully has solved a major headache we all have when we attempt to go thru the trial and error and frustration with getting the random wire to work where WE want it to work. 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. endobj /Subtype /Image He was so impressed that he purchased a 9:1 unit from you, his will be delivered Saturday. ones The graph below shows lengths to avoid for different collections of bands. Contact SBULLET-9U-1500. It will be good for 15m, and 10m. The Short Answer Would Be That an UnUn Is a "UN balanced to UN balanced" matching transformer. As typically Dimensional Drawing of Standard Enclosure, 1:1 Common Mode Choke / Noise Suppression, Core Material Selecton for Baluns and Ununs, Antenna Matching Problems When Using Ladder Line or Open Wire Feedlines, Model 4932 - 4 & 9:1 Unun 1.5 - 54MHz - 2kW, Model 49130 - 49:1 - 80-10m EFHW - 200 watts, Model 64131e - 64:1 & 49:1 - 80-10m EFHW - Up to 1kW, Model 4116 - 4:1 Hybrid Balun 1.5 - 54MHz 3kW, Model 9130sw - QRP 9:1 Unun 1.5 - 54 MHz - 300 watts, Model 1115d - Max Choking 1:1 Balun, 1.5-54 MHz, 5kW. Drill out holes in the designated bottom of the electrical junction box for the SO239 chassis mount. /Name /Im0 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA << bands you're intested in in a vector like the example below, by typing. Support The Site 2. Random wire lengths you should and should not use! Note: My (A to B) length was 6 inches. A VSWR sweep of the unun after adding a 100pF capacitor shows an SWR <5:1 from 160M to 10M. I only used two screws instead of four. The graph below shows lengths to avoid for different collections of bands. Following the directions exactly as specified (0.47wl / 0.05wl matching counterpoise) and drilling two weep holes in the appropriate position, I had a 10 meter EFHW antenna up in less than ten minutes. , This is a partial reprint (with permission) of an excellent series of articles published by KV5R 40-30-20 . Work all bands from 80 through 10 on it. 35. An end fed half wave antenna is one of a specific length depending on the frequency that it is to be used on, for example, an end fed half wave antenna for 80 meters is about 130 long. First, it is important to understand the difference between the end fed half wave and a random wire (or "long wire") antenna: the random wire is just a piece of wire that is matched to 50 Ohm impedance using an antenna coupler, sometimes adding a 9:1 unun. Let's have a look at a few details on how to build a 49:1 impedance . So I just wanna say thank-you!! This transformer is designed to be used with an end fed half wavelength of wire only. At this point, Ive only used the 49:1 tap, but plan to take the 64131 whenever I operate portable. If you plan on stringing up a dipole you use 2 equal lengths of wire with the Balun in the middle. /Creator (XnView) The following wire connections do not need to be made in the order I described. endobj The second smallest number I measured was 2.7pF, derived from the self resonance at 2.72 MHz with the magnetizing inductance (measured at 25.8 H) with the secondary open and the output wire folded to a small 1/2 length. The First Thing New Hams Often Ask:What Is An UnUn? ?7{*. I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. endobj tuner the colored bands below are the best lengths as long as your Alternate connectors and Mounting Options are available in the. (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. Each winding is counted when the wire enters through the center hole of the toroid. 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. Well then you need to choose a wire length that is at least 1/4 on 40 meters, and doesn't fall on any of the 1/2 multiples for ALL the bands between 40 to 10 meters While you could certainly calculate the lengths to avoid using the standard formulas, and then make a chart, the section below may be what you are looking for. << x@ << Superior Essex Heavy build polyamideimide. SO-239 connectors are silver plated with Teflon insulation. 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 . When used with the stated lengths shown in thetable below, the 9:1 ratio will Based on the success of our model 4932, this 5kWconfigurationisalso perfect for matching both long and short length wire antennas for multiband use. Cut the ground wires (free twisted short and long wires) of the unun to the correct size, scrape the enamel insulation off of the free end with a box cutter, and add a ring terminal. For reasons that I do not understand, adding a capacitor between the coax conductor wire (untwisted free end of short wire) and the ground (twisted free ends of long and short wire) can increase the functional bandwidth of the antenna on the higher HF frequencies. This project assembles a 49:1 ferrite-core ("FT") type #43 transformer that matches 50 ohm input to 2500 ohm end fed antenna. Shortwave Listening We are working every day to make sure our community is the best Radio Hobbyist's site. 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. Stacked coreswithwinding configured as 49:1auto transformer. Here is an ARRL 4 0 obj | I actually did this first and before the connector was bolted to the box. SWR was good after cutting the wire to appropriate length. Picture 1 of 9. It may not display this or other websites correctly. Post Reviews Jack, VE3EED - SK. A standard recommendation (see QST, March 1936, p. 32, "An Unorthodox something as high as you can find. /Kids [ 4 0 R ] Thanks for your answer,I will probably go with the 9:1 then. 49:1 UNUN IMPEDANCE XFORMER FOR END FED HALF WAVE ANTENNA. is helpful if you're in a hurry to get on the air, read up on the topic 1 0 obj Tune Around! Modify bands and Longer wire is always more If you want a single band portable antenna you can mount pretty much however, look up this design.
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