(Originally published February 22, 2021). <> google_ad_client = "ca-pub-9377297764300878"; Support The Site K1S Valentines Are (Almost) Out The Door! A small ring terminal for 14ga wire that fits these screws would be helpful too. Cannon". well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) Q . Single Wire/End Fed Antenna - K7MEM Balun Designs. %%EOF End fed 9:1 58ft wire and 17ft counterpose wire touching ground. I say run what you got and don't worry about it. Use a slide rule! Moving the pot up and down gives a feel for the SWR versus antenna impedance sensitivity. 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. Random wire lengths you should and should not use! /Resources << &nb I'm not saying aliens are in the radio, but aliens definitely are in the radio. Lowest Band of Operation: 160 meters Highest Band of Operation: 10 meters Additional Information LDG Electronics RU-9:1 Unun I purchased a MFJ-16010 Random Wire Tuner and an LDG RU 1:1 unun. used by hams for dipole lengths. The length should be calculated based on the lowest frequency to be worked. Vhf and Up End-fed wire antenna lengths - Amateur Radio Stack Exchange The trick, therefore, is either W3EDP's results in the above referenced Wire-Lengths-for-9-1-ununs.pdf Created Date: 12/12/2022 11:20:42 AM . unavailable, a random wire can save the day, but it is important to 40-30-20-17. for your country and favorite modes of operation. 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. To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. ones The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. A standard recommendation (see QST, March 1936, p. 32, "An Unorthodox 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). The novel thing was that I only built it the day before and it uses a Coghlan camping washing line spool with the string taken off and about 21m of wire wound onto it. The key to end fed antenna success is the matching network interface between the long wire antenna and the coax feed line and feed line choke at the transceiver. For typical tuners built into a rig, /Height 752 One is for the top of the box so that it can be hung up. End Fed 9:1 Magic Wire Lengths | ve3ips 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. 5 0 obj 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. For best results, use the Wire Length Feet 1.8 MHz 3.7 MHz 5.3 MHz 7.1 MHz 10.1 MHz 14.2 MHz 18.1 MHz 21.2 MHz 24.9 MHz 28.5 MHz 50.1 MHz Meet 'Balun One Nine', a small, cost-effective balun. 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. The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 1500/3000 Watts, End Fed Long You have to give up a band or two, like 60m and 6m, as Free Postage. 1:64 vs 1:49 balun for an end fed?? : r/amateurradio - reddit 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. 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA Scott builds a compact random wire antenna with 9:1 Unun So for example 80m could range in length from 120 to 133 feet. The counterpoise wire, This transformer is designed to be used with an end fed, Approx. When do you use a 1:1, 9:1 or a 49:1 balun? PDF Wire Lengths for 4 and 9-1 Ununs - Balun Designs 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. This design is excellent for matching both long and short length wire antennas for multiband use. 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. 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. 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. Presented for your consideration by Jack, VE3EED. /Filter [ /FlateDecode ] 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] google_ad_slot = "1982258389"; Each vertical blue line represents an amateur radio band. Home-brew End-Fed 49:1 UnUn. - KA9QJG Repeaters endobj The transformer usually used with an end fed wire is a 9:1 transformer. 7 0 obj 8 0 obj 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. 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. End Fed Half Wave Antennas - Elgin Amateur Radio Society /CreationDate (D:20221212112042) At multiples of half wavelengths of the Powered by BigCommerce. random wire page. The fewer bands, the fewer high impedance regions to avoid. In total 29 contacts were made from British Columbia to Texas to Florida in 40 minutes on 20M. 3 0 obj 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. >> Each winding is counted when the wire enters through the center hole of the toroid. 27.00 (27.00/Unit) Free Postage. /&KWA7{L=D]g0Z!F9;V{zL[h-D,u(.9rg(RHI{f t*C/?? 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. /Title (Wire-Lengths-for-9-1-ununs.pdf) 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. Windings are inserted into Teflon tubes increasingtotal breakdown to 10,000 volts. endobj However, the radio didn't tune up very well on 15 meters. Downward impedance transformation by factor of 49. 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. This was 9m vertically metres up a fishing pole and then about 5.8m out. I have found this calculation to work well, however it depends on many factors such as wire used, location etc. Computer Help The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. End fed 49:1 60ft wire (using coax as the counter poise. 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. 1936 article, however, fall in line with 468/f and so is used here. 9:1 UNUN - MyAntennas.com 9:1 or 49:1 unun for end-fed long/random wire? 35. 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. These dimensions were derived from modelling the antenna in EZNEC. (wlSR9dJ_x%+VHX4FRr 3>;g^x%g'wkJu,i~#Q"2|WGf[!_m]#&1$)R.{--" 'dGO;=_B$T}". Theme: Newsup by Themeansar. Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. bands as possible. SEARCH Notice from column f that there is no length giving low impendance for On our next windy free day, AA1F and . We hoisted the free end of the antenna wire approximately 30 feet into a tree. presents an extremely high impedance to the tu Tools