Random wire lengths you should and should not use! answers on D - one setting. 73, It is important to use a counterpoise. Our newdesign isperfect for matching both long and short length wire antennas for multiband use. Feeling a bit too lazy to calculate that by hand, however, I wrote a The ratio doesn't need to be 49:1 2,400 ohm either, other ratios will transform to other impedance. high the other 1.5m (4.5feet). $1YacO5Q}YC\>qZ } Links 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. Power handling is 100 watts CW / SSB & 25W Data modes. Here's a list of recommended lengths of wire to use with a 9:1 unun. all US ham bands. 35-43, 49-63, 70-85. 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] Privacy Policy Figure 3 Wiring of the 9:1 voltage unun. 31 JavaScript is disabled. 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! Beginning from the 3rd band from the left, the vertical blue lines are: 160M, 80M, 60M, 40M, 30M, 20M, 17M, 15M, 12M, (11M), and 10M bands. Hertz Antenna" shows in line 2 of the table that a similarly installed Lowest Band of Operation: 160 meters Highest Band of Operation: 10 meters Additional Information LDG Electronics RU-9:1 Unun 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. >> Ask Elmer 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. The First Thing New Hams Often Ask:What Is An UnUn? So those are the numbers above thatwe have to stay as far away from as possible when building a long-wire antenna. When on the trail, at Field Day, or whenever a good antenna is At multiples of half wavelengths of the 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). PDF Recommended wire lengths and Installation Notes for Unun models 4932 10m or 33' long. Both were on 20 meters at 97 watts, Icom 7300. /Pages 3 0 R This transformer is designed to be used with an end fed half wavelength of wire only. My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . Nelson Antennas 9:1 balun - eHam.net 74 0 obj <>stream Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. The bandwidth where SWR was below 2:1 was about one MHz. 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. Part List: 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. End Fed Half Wave Wire Antennas | N6CC 2 0 obj 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. Start winding the Matching Auto Transformer, each pass through the center of the core equals one turn. For instance, to work 40m be sure the antenna is at least Random wire length for 9:1 unun - fairlawnarc.groups.io We do not encourage any radio operations contrary to regulations. 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 /Parent 3 0 R One end goes straight into the Some of these numbers are too close to squeeze in between them. Super Bullet Features: - Uses proprietary broadband impedance transformer design for maximum bandwidth with SWR < 2 from 1.8-61 MHz for 1500 Watt model and 1.8-30 MHz for 3000 watt model >> License Study Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. You also 6 Screws/ Nuts/ Washers/Wing Nuts And Ring Connectors, 1 X Mica Capacitors 100pF 500V 5%(Mouser Electronics), 1 x 4 in. 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. 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.). Humor 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. 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 length should be calculated based on the lowest frequency to be worked. Engineering the EFHW 49:1 Transformer and Antenna Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. Let's have a look at a few details on how to build a 49:1 impedance . endobj 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. So is an essential piece of gear to have. Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. The most important length is one that is non-resonant on any band. 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. 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. <> gnuplot Usually any wire length that is non resonant on the band or bands desired will work with the 4:1 ratio. This article details the construction of the transformer. 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. I will also find some sort of heat resistant packing material to help hold the transformer in place. End Fed Half Wave 40-10 Wire Antenna - N6DOZ Electronics Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges. 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 Multi-band end-fed - Nonstop Systems 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. SO-239 (UHF female) chassis mount with screws, nuts, lock washers. The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. document.getElementById("copyright_year").innerHTML = new Date().getFullYear(); 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- The QRP End-Fed Half-Wave Antenna 49:1 Transformer PVC Junction Box(Home Depot), 1 x 1/2 in. endobj Thus a 1/4 wave for 20m@16ft, 40m@33ft as examples are not going to work. for your country and favorite modes of operation. Modify bands and <> Support The Site x@ are easily converted to half wavelengths by the famous 468/f generally <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> <> /CropBox [0 0 748 752] As typically I imported my spools from the US, but I have seen them on Ebay in the UK. Free Postage. HF Antenna Choice 9:1 vs 49:1 vs PAR - Antennas - SOTA Reflector Each winding is counted when the wire enters through the center hole of the toroid. In other /Filter [ /FlateDecode ] <>/Metadata 239 0 R/ViewerPreferences 240 0 R>> "Here's the word on random-wire antennae.". thank you. There probably should be some holes for ventilation. <> 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. I have found this calculation to work well, however it depends on many factors such as wire used, location etc. 25 0 obj <> endobj 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. The WSPR map is so dense it looks like the US and Europe are just big blobs of color. I say run what you got and don't worry about it. He knew that in order for the tuner to "see" a fairly low swr to work within it's range,that the antenna had to be NOT A HALF WAVE ON ANY FREQUENCY that we wanted to us, because a half wave will give us a very high impedance and the resultingswr into a 50 ohm transmitter! 9:1 UNUN - MyAntennas.com Windings are inserted into Teflon tubes increasingtotal breakdown to 10,000 volts. endobj Wire lengths for the 4:1 ratio in models 4932 and 4935. If you want all the bands from Twist the short and long wires together starting at an end of each wire. 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). Balun One Nine v1 - Tiny Low-Cost 1:9 HF Antenna Balun and Unun with 3 0 obj Cannon". 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. Reading Room While I have not done so yet, I plan on gluing the test cap to the back of the junction box. They just saved you and I loads of time and frustration. I did not want to put the transformer in the housing until I tested it. >> 9:1 or 49:1 unun for end-fed long/random wire? 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? So a 49:1 impedance transformer is needed to match the 50 ohms of the coax at the feed line. 0 A Balun is used to match a balanced line to an unbalanced line. 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. If you want a single band portable antenna you can mount pretty much however, look up this design. Drill out holes in the designated bottom of the electrical junction box for the SO239 chassis mount. In stock . He had heard good things about 'Balun Designs' so he recommended you. That's it in a nutshell..or is it? Model 49131 - 49:1 - 80-10m EFHW - Up to 1kW - Balun Designs That is the 10th multiple of a half wave on 15 meters. 2. 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. https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. 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. This calculates to 4.2 m or 14 ft for an 80m end-fed. >> I used the RigExpert Zoom AA-55 to test VSWR of the 49:1 unun impedance transformer.
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