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!! 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. In another life, I could have been a telephone engineer. Recommended wire lengths for Unun models 9130, 9132 & 9135 Table shows typical SWR relative to installed wire length. unavailable, a random wire can save the day, but it is important to The fewer bands, the fewer high impedance regions to avoid. In fact, the 9:1 unun that I built is actually an autotransformer. 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. X:nzf4p:t;r }~_HOZcX:^$* J^XZuu|"nX/Wkw0hA>y1(z2+v_Xzu[/:^$*m*>hk_:+c{ Code Practice AndWhat Is It Used For In Antennas? A standard recommendation (see QST, March 1936, p. 32, "An Unorthodox Wire lengths for the 4:1 ratio in models 4932 and 4935. I purchased a MFJ-16010 Random Wire Tuner and an LDG RU 1:1 unun. endstream Ham Radio Videos! I'm not saying aliens are in the radio, but aliens definitely are in the radio. The unun was floating at about 15 feet above ground. Site Map The short piece is for the primary winding of the transformer, and the long piece is for the secondary winding of the transformer. 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. 3 to31 MHz - up to 1kW intermittent (50% duty cycle). /Title (Wire-Lengths-for-9-1-ununs.pdf) The matching unit The impedance at the end of a half wave antenna is somewhere between 2000-5000 Ohms. 9:1 Unun EF Random Long wire matching Transformer with BNC or SO-239. 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. For those that enjoy the LNR and Hy Endfed antennas, but want to run more power, Balun Designs now offers an excellent alternative. endstream endobj startxref Use only the white gaps for your antenna lengths, and if 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. and leave the unun on the ground. endobj /Count 1 Product Reviews You'll want to have that wire up as high as you can get.. Here's a list of recommended lengths of wire to use with a 9:1 unun. (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. bands as possible. Moving the pot up and down gives a feel for the SWR versus antenna impedance sensitivity. x 4 in. Ham Hints Humor 9:1 Unun 1.5-54MHz 2kW 9132S. 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). 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. 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA 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. I actually did this first and before the connector was bolted to the box. Here Is a 250 Watt Home-Brew That I Made In about an Hour. Anyway, an old friend mentioned 'MyAntenna.com' but they were closed for the summer. Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges. Quantity: Sold individually. Proudly powered by WordPress JC[ d8O[UKKQ{yZ{G 'Upno_*~8uo a@G`' zxUHXW&`}mEp`?i0 oE:N0-/t"t.-? The transformer usually used with an end fed wire is a 9:1 transformer. 74 0 obj <>stream stream , Most matching problems occur when the antenna system The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. 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. frequencies for your country or favorite modes. rig, often with no feedline, and the other end in the air attached to /ModDate (D:20221212112042) Par EF 20 and par EF 40 (I realize for 17m I would prob just add that band to a 49:1 balun) That's that my question is. << 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. It will be good for 15m, and 10m. A VSWR sweep of the unun after adding a 100pF capacitor shows an SWR <5:1 from 160M to 10M. End fed 9:1 58ft wire and 17ft counterpose wire touching ground. 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. That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . (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. thank you. For example, when adding a 1/4w tiger tail to a 2m ht with a halfwave for antenna will likely show no improvement at all in tx or rx strengths. 35. 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. We do not encourage any radio operations contrary to regulations. Well, I didn't think it would make any difference at that many multiples. 27.00 (27.00/Unit) Free Postage. answers on D - one setting. << NOTE: Rewording the previous paragraph, if you have a capable enough In stock . You will note that when comparing my results with VE3EED that some of the results are a bit different. 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. Tune Around! SO-239 connectors are silver plated with Teflon insulation. Then verify it with your installed antenna and SWR measurements. 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. 40-10m with a 49:1 Unun. << 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. 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. Technical specification : Type : 49:1 Unun Frequency : 1.81 MHz - 30MHz Impedance ratio: 1:49 Input Impedance: 50 Output Impedance: 2500 Power Handling (CW/SSB) : 250W Core Type : 1x FT240-43 by Fair-rite Co. Capacitor 100pF 3KV Assembled and tested. >> The length of a half wave antenna is calculated using the following formula: L (ft) = 468 / f (freq in mhz). This will be for an eyehook in order to provide strain relief for the radiator wire. Vhf and Up I use this 8010 EFHW at home, too. 8 0 obj 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. My homemade 49:1 EFWH with a 60 wire (cut for 40M) would do just fine! This homebrew 49:1 impedance transformer is the heart of any EFHW antenna you will build, most of the time. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. is that for a given ham band there are min and max frequencies which For calculating the length of a half wave in metres, I use 141 (MHz) for wire elements. /Pages 3 0 R 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. June 8, 2022 at 9:17 am. ?7{*. This may not be relevant to HF stuff, but the antenna I use for NDB reception has a 400:1 transformer (20:1) turns ratio. You also 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 Balun Designs unit is replacing an MFj 1982 HP EFHW balun that was DOA when it arrived last May. STORE 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 . 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. well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) Multiples are on C and 1. You have to give up a band or two, like 60m and 6m, as An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). Thus a 1/4 wave for 20m@16ft, 40m@33ft as examples are not going to work. Continue twisting the entire length of the short wire. results. Theme designed by Papathemes. He was so impressed that he purchased a 9:1 unit from you, his will be delivered Saturday. As typically Let's have a look at a few details on how to build a 49:1 impedance . <>/Metadata 239 0 R/ViewerPreferences 240 0 R>> The 30 day return period lapsed before I could get the antenna deployed to test it. I only used two screws instead of four. and experiment. N4UJW. /CropBox [0 0 748 752] % so that it is not a halfwave multiple of any frequency you want to use. Using a 49:1 transformer shoot for the best 50 match @ appx 2450 load over your working frequency bands. Figure 2 Schematic of the 9:1 voltage unun . This was 9m vertically metres up a fishing pole and then about 5.8m out. Thanks for your answer,I will probably go with the 9:1 then. A way of connecting the analyzer to the transformer. << The QRP End-Fed Half-Wave Antenna 49:1 Transformer Building a great impedance transformer for Ham Radio end-fed wire antennas. License Study Antenna Design A so-called random wire antenna is an end fed antenna. /Type /Page PVC Junction Box(Home Depot), 1 x 1/2 in. So, having nothing better to do one day, I re-did the calculations going out to 500 feet. Longer wire is always more 49:1 UNUN IMPEDANCE XFORMER FOR END FED HALF WAVE ANTENNA. Both were on 20 meters at 97 watts, Icom 7300. I used 2000 and 1000 ohm resistors in series connected to the proper unun wires with alligator clips for a total of 3000 ohms. /Parent 3 0 R want the antenna to be at least 1/4 wavelength long for each band you Advertising Info Links The bandwidth where SWR was below 2:1 was about one MHz. <> 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. ", KiwiSDR Online Radio - 500 ft Northeast Beverage, KiwiSDR Online Radio - 400 ft South Beverage, KiwiSDR Online Radio - 10/11m dipole up 20 meters high. /Im0 Do (wlSR9dJ_x%+VHX4FRr 3>;g^x%g'wkJu,i~#Q"2|WGf[!_m]#&1$)R.{--" 'dGO;=_B$T}". 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. The vertical (y-) axis shows the VSWR and the horizontal (x-) axis shows the frequencies. Clansman End Fed Long Wire Antenna Used. >> The following wire connections do not need to be made in the order I described. The Nelson antenna 9 to 1 unun did the trick. it is easy to pack and easy to install. Enclosure Depth: 1.250 in. SWR was good after cutting the wire to appropriate length. You need to use these lengths and the longer ones . 2 0 obj 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. Turns 1 & 2 are primary windings (the short wire). 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. 4 0 obj 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. The random wire antenna is probably one of the least expensive, easiest and cheapest HF antennas to use if you have a tuner and you want to get the "most" out of a length of "random" wire without having to pull out that calculator, doing the math, getting the center insulator built orbought, running the feedline, and all the rest that goes with putting up a more elaborate antenna. 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. https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. If the transformer is used with an externaltuner in conjunction with a single wireantenna typically 130-135 feet in length, power should be reduced on those bands that show an SWR above 1.6 to2:5 withoutthe tuner. <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> It is used fornon-resonant verticals like 43 foot or 33 foot Or Wire antennas like an End-Fed1/2 Wave Multiple Length Wire Antenna. I used a homemade jig made of an SO239 chassis mount to bare wires, alligator clips, and a coax-jumper with PL259 (UHF male) ends; see picture below. WwS`8o}=n,pjhzRa]Ju/Ru ni4=UvZ:u9*@ Xz+zZcXm}i[Z;Z>.u!*eQVjucXeqYZnSJu)U[n>>KXzZ.Lz sqxcGj]%q}i6=-?YTlnZXV6}=U >5`ZNxChzRa]JU.6TVr6a] x@ 3 0 obj /Type /Pages 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. It's an efficient way to get all the multiples Use with other lengths can potentially damage the transformer depending on power level in use. 73, Shortwave Listening recommended on VE3EED's page because I use all halfwave 5 0 obj 9:1 or 49:1 unun for end-fed long/random wire? 6 0 obj 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. Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 1500 Watts, End Fed Antennas. . 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. The WSPR map is so dense it looks like the US and Europe are just big blobs of color. Please note that I will not be describing the construction of the antenna wire radiator here. At multiples of half wavelengths of the Winding 1:64 Matching Auto Transformer on the FT240-43 core. Technical specification : Type : 49:1 Unun Frequency : 1.8 MHz - 7.3 MHz Turns ratio: 1:7 Impedance ratio: 1:49 Input Impedance: 50 Output Impedance: 2450 Power Handling (CW/SSB/ Digital Modes) : 2Kw of peak power / DM Modes 500 watts Core Type : 3 x FT240-43 by Fair-rite Co. Wire type: Enamel copper wire 2.0 mm (AWG 12) Assembled and tested. Ask Elmer You have to stay away from a half wavelength on any frequency. Palomar Engineers employs a dual core matching system that offers wide bandwidth (1-61 MHz), 500 watt PEP rating, and a connection for a counterpoise or ground if desired. The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? bands you're intested in in a vector like the example below, by typing. an auto-tuner at the base vs. the same antenna fed a 4:1 balun wound with 75 ohm coax on two separate type 43 ferrite cores and a remotely sited tuner fed via 200ft of low loss LDF2-50 coax vs. a broadband antenna of the same element length. Save program output in file named 'f', and use . u?X`f0&/Ri;W0Tn_*TX:ug 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). /Producer (XnView, http://www.xnview.com) That's it in a nutshell..or is it? /Length 10 0 R gnuplot %PDF-1.5 Again, the bands are USA, so change them VSWR analysis of the antenna in the field showed that VSWRs between 3-5.5 from 40M to 10M. I used the RigExpert Zoom AA-55 to test VSWR of the 49:1 unun impedance transformer. 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. . Just add or subtract as needed a little at a time to get the best compromise. For instance, to work 40m be sure the antenna is at least Drill another hole in the same side as the antenna radiator wire mount hole. you're using different ham bands than in these examples, modify and rerun << high the other 1.5m (4.5feet). random wire page. stream Ham Satellites The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. >> So for 80 meters (say 3.525 MHz) this gives you about 133' of 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. var sc_invisible=1; 10m or 33' long. The 49:1 impedance transformer will help you bring down the high impedance of your resonant EFHW antenna to almost 50 Ohm. endobj Each vertical blue line represents an amateur radio band. Y &lD30. Repeater Basics Hopefully these random wire length calculations will help us all make this "easy" antenna work better! So a 49:1 impedance transformer is needed to match the 50 ohms of the coax at the feed line. K1S Valentines Are (Almost) Out The Door! (The numbers aboveare a great start, thanks to Jack and Mike! Theme: Newsup by Themeansar. JavaScript is disabled. 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. The trick, therefore, is either That is the 10th multiple of a half wave on 15 meters. /Name /Im0 Care to buy us a beer? 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. When on the trail, at Field Day, or whenever a good antenna is I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. are blocked out because an antenna should be at least that long. The ratio doesn't need to be 49:1 2,400 ohm either, other ratios will transform to other impedance. A png image named g.png will be created. wire lengths less than 1/4 wavelength of the lowest desired frequency 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. endobj endobj (Also check out AB3AP'Swebsite and say thanks for sharing his skills.
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