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. 40-10m with a 49:1 Unun. x@ 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. EFHW Antenna and 49:1 UnUn | WorldwideDX Radio Forum Engineering the EFHW 49:1 Transformer and Antenna Twist the short and long wires together starting at an end of each wire. 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. Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 1500/3000 Watts, End Fed Long Because I had some spare Cu-Wire I wound another 1:49 Unun on a smaller FT-140-43 toroid and tried different capacitors between feedline and ground (to compensate for the 10m band). 9:1 Unun EF Random Long wire matching Transformer with BNC or SO-239. Cut the center conductor wire (free untwisted end of short wire) of the unun to the correct size, scrape the enamel insulation off of the free end with a box cutter, and solder it to the SO239 connector. 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 . Powered by BigCommerce. One is for the top of the box so that it can be hung up. 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. Weight: 0.380 lbs. Care to buy us a beer? want the antenna to be at least 1/4 wavelength long for each band you hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. doing the initial 468/f on C and D scales. End Fed Antennas - Elgin Amateur Radio Society 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. Drill a hole in the top for an eyehook (to be used to secure the unun to whatever it is you want to hang it from.). Use with other lengths can potentially damage the transformer depending on power level in use. endobj How We Flew An End-Fed Half Wave (EFHW) Ham Radio Antenna On A - KM1NDY . Multi-band end-fed - Nonstop Systems Well, I didn't think it would make any difference at that many multiples. My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . Balun Designs. config file by typing gnuplot rw.gnu. $1YacO5Q}YC\>qZ } 7 0 obj There probably should be some holes for ventilation. The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. so that it is not a halfwave multiple of any frequency you want to use. The "Almost Random" Wire Antenna - KB6NU's Ham Radio Blog It may not display this or other websites correctly. (Center fed is so appealing because you avoid this.). for your country and favorite modes of operation. (The numbers aboveare a great start, thanks to Jack and Mike! 80m up, W3EDP's 84' antenna, 17' counterpoise is probably the way to go. He used 300 ohm twin-lead and a 4:1 UNUN, with a 1:1 current choke between the UNUN and the coax to the tuner and transceiver: The full-size "flimsy" (ref. The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? 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. /Title (Wire-Lengths-for-9-1-ununs.pdf) The idea When on the trail, at Field Day, or whenever a good antenna is I made one without doing this and it didn't work so well. That's it in a nutshell..or is it? Just an FYI that I thought you might be interested in. << I have found this calculation to work well, however it depends on many factors such as wire used, location etc. InJack's own words. wire lengths less than 1/4 wavelength of the lowest desired frequency End Fed Antennas. /Width 748 google_ad_height = 600; Stacked coreswithwinding configured as 49:1auto transformer. Drill a hole in one side for the antenna radiator wire mount (for a #8 bolt in my build). Unun 9:1 - VK6YSF - Home Page Use with other lengths can potentially damage the transformer depending on power level in use. 35-45, 54-64, 67-77. 49:1 UNUN IMPEDANCE XFORMER FOR END FED HALF WAVE ANTENNA. Prescott Hamfest - W7YRC 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. In stock . , The "Best" Random Wire Antenna Lengths /Filter [ /FlateDecode ] It will be good for 15m, and 10m. /BitsPerComponent 8 stream You'll want to have that wire up as high as you can get.. PDF Wire-Lengths-for-9-1-ununs - OM0ET FCC Information You can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. A few more comments about this 49:1 autotransformer EFHW design. The "Super Bullet" End Fed Long Wire Antenna Matcher - 1500/3000 watt rated for Super-Punch of your signal! HF Underground wiki Radio Hobbyist technical blogHFU Discord EuroPirate ChatPropagation DataTeamspeak Server, TDK CXA-2090 LCD Inverter Module New Old Stock USA Seller $19.99, Shortwave Pirate Radio In North America And Around The World, And Other Signals That Go Bump In The Night, Login with username, password and session length. endobj Experimenting by slightly changing the wire length (+ or-) is encouraged to provide best overall performance. A success! 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. Nelson Antennas 9:1 balun - eHam.net Random wire length for 9:1 unun - fairlawnarc.groups.io For typical tuners built into a rig, Modify bands and This type of antenna is very easy to install because there is no need . Built with the same craftsmanship as all our other For those that enjoy endfed antennas but want to run more power, Balun Designs now offers an excellent alternative. 0 For a better experience, please enable JavaScript in your browser before proceeding. NOTE: Rewording the previous paragraph, if you have a capable enough Proudly powered by WordPress This was 9m vertically metres up a fishing pole and then about 5.8m out. Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 1500 Watts, End Fed Antennas you're using different ham bands than in these examples, modify and rerun Here Is a 250 Watt Home-Brew That I Made In about an Hour. A VSWR sweep of the unun after adding a 100pF capacitor shows an SWR <5:1 from 160M to 10M. Part List: 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. I used the RigExpert Zoom AA-55 to test VSWR of the 49:1 unun impedance transformer. So a 49:1 impedance transformer is needed to match the 50 ohms of the coax at the feed line. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. 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. stream Model 49131 - 49:1 - 80-10m EFHW - Up to 1kW - Balun Designs In addition to multiples, Drill another hole in the same side as the antenna radiator wire mount hole. Therefore, we came up with the following numbers to avoid (IN FEET): These lengths in the table beloware the culprits that cause all of the trouble when using random lengths. /Length 10 0 R I attached the toroids to a PVC DWV test cap with 3 cable ties. endobj uR5ucE`_aksLjYT=hzRa]JucX7d}|'}`XRa>X Hopefully these random wire length calculations will help us all make this "easy" antenna work better! rig, often with no feedline, and the other end in the air attached to << . The fewer bands, the fewer high impedance regions to avoid. Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. endstream endobj startxref 1 0 obj Vhf and Up % To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. RFI Tips and Tricks Thanks for your answer,I will probably go with the 9:1 then. well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) Some of these numbers are too close to squeeze in between them. 35. 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. PDF Recommended wire lengths and Installation Notes for Unun models 4932 Computer Help Start winding the Matching Auto Transformer, each pass through the center of the core equals one turn. End Fed Half Wave Antenna Coupler (EFHW) - M0UKD The trick, therefore, is either However, the radio didn't tune up very well on 15 meters. So I just wanna say thank-you!! 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. 9:1 UNUN - MyAntennas.com Turns 1 through 14 are secondary windings (the long wire). The "9:1 UNUN" are for random length wire antennas fed at the end. << 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. K1S Valentines Are (Almost) Out The Door! You can add your own wire or get the complete product from this link EFLW-3K antennas. NEMA rated 4x marine grade junction box for outdoor installations. Recommended wire lengths for Unun models 9130, 9132 & 9135 Table shows typical SWR relative to installed wire length. The 30 day return period lapsed before I could get the antenna deployed to test it. To summarise the results WRT to reference antenna consisting of 30ft wire vertical fed with auto- End Fed 9:1 Magic Wire Lengths | ve3ips Wait a few minutes for glue to set. endobj Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. In total 29 contacts were made from British Columbia to Texas to Florida in 40 minutes on 20M. /Type /Page STORE Continue twisting the entire length of the short wire. Just add or subtract as needed a little at a time to get the best compromise. ones So is an essential piece of gear to have. 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA I wrote a small C program that does just what Jack did, butI used the band edges. but instead of the Jaycar core, we used an Amidon FT-240-43; anyhow, we also followed the UnUn with a 1:1 guanella choke and boxed everything, at that point, we . 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? frequencies for your country or favorite modes. 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). Random Wire Antenna Lengths - University of Delaware I actually did this first and before the connector was bolted to the box. 3 0 obj Enclosure Depth: 1.250 in. The ratio doesn't need to be 49:1 2,400 ohm either, other ratios will transform to other impedance. Multiples are on C and 49:1 vs. 9:1 Transformer for RX only? - RadioReference.com Forums stream /Resources << You have to give up a band or two, like 60m and 6m, as I purchased a MFJ-16010 Random Wire Tuner and an LDG RU 1:1 unun. Usually any wire length that is non resonant, like those shown above, will work with the 4:1 ratio. JC[ d8O[UKKQ{yZ{G 'Upno_*~8uo a@G`' zxUHXW&`}mEp`?i0 oE:N0-/t"t.-? q Support The Site I sent him the link to the 49:1 unit to get his feedback. and leave the unun on the ground. The WorldwideDX Radio Forum was originally established in 2001. Generally an EFHW will be in the range of 2,000 to 5,000 ohms at the very end of the dipole when resonant. SO-239 connectors are silver plated with Teflon insulation. 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. Alternate connectors and Mounting Options are available in the. 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. 9:1 Unun 1.5-54MHz 2kW 9132S. tuner the colored bands below are the best lengths as long as your >> 20/40/17m. This is not exactly a 1/2 wavelength in free space, but works for wire as it has a different velocity factor than "air". A level of 500-600 watts is the maximum with a further reduction onany band measuringabove 3:1. endobj You are using an out of date browser. /* Ad banner 160 x 600 */ Kj8~q7c? About Hamuniverse So, if you connect a length of wire that presents an impedance of about 450 to the input, you'll get an impedance of about 50 on the output. How to Make a Balun or Unun : 3 Steps - Instructables 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. . Enclosure Height: 5.000 in. Legal Stuff 1936 article, however, fall in line with 468/f and so is used here. That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . The following wire connections do not need to be made in the order I described. PDF 33ft Verticals and 4:1 Ununs - G8JNJ /Type /Pages Random Wire Antennas - Best Lengths To Use For Random Wire 27.00 (27.00/Unit) Free Postage. thank you. W3EDP's results in the above referenced Advertising Info He had heard good things about 'Balun Designs' so he recommended you. 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. 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!! However, the list has been revised and is good for wires as long as 500 feet. Jack, VE3EED - SK. Built with the same craftsmanship as all our other units, this new model will allow you to either replace your current matching unit or construct a new higher powerend fed half wave 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). Anyway, an old friend mentioned 'MyAntenna.com' but they were closed for the summer. 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. %PDF-1.7 /ColorSpace 11 0 R 9:1 UnUn End Fed Long Wire Lengths - Pretty Simple | ve3ips These are sometimes known as a Magnetic Longwire Balun. 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. <>>> 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. Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. Single Wire/End Fed Antenna - K7MEM 40-30-20-17. <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> 4 0 obj PVC Junction Box(Home Depot), 1 x 1/2 in. /Height 752 In fact, the 9:1 unun that I built is actually an autotransformer.