understand its properties. | Drill a hole in one side for the antenna radiator wire mount (for a #8 bolt in my build). 35. For a better experience, please enable JavaScript in your browser before proceeding. Let the now free end of the short wire hang down from the toroid. 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 Y &lD30. 80m up, W3EDP's 84' antenna, 17' counterpoise is probably the way to go. 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. 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. So I just wanna say thank-you!! The idea Let's have a look at a few details on how to build a 49:1 impedance . Prescott Hamfest 2023 Saturday - May 13, 2023 - 0800 to 1200 MST Granville Elementary School 5250 Stover Drive, Prescott Valley, AZ 86314 The 2023 Prescott Hamfest is co-sponsored by the Yavapai Amateur Radio Club (YARC) and the Amateur Radio Council of Arizona (ARCA). This article explains why the use of mix 43 for HF applications is almost always a mistake. 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. high the other 1.5m (4.5feet). Start winding the toroid with the twisted wires at loop #1 (see schematic below). In stock . To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. We'd really appreciate it! 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. /BitsPerComponent 8 It's an efficient way to get all the multiples 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. Figure 2 Schematic of the 9:1 voltage unun . Connect this ring terminal to one of the SO239 chassis bolts. Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. Use with other lengths can potentially damage the transformer depending on power level in use. /Type /Page /Kids [ 4 0 R ] rig, often with no feedline, and the other end in the air attached to . google_ad_height = 600; The 30 day return period lapsed before I could get the antenna deployed to test it. and leave the unun on the ground. 3 0 obj Drill another hole in the same side as the antenna radiator wire mount hole. 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. /Parent 3 0 R (A t0 B) Fold over 6 to 8 inches and twist it together. results. 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 A small ring terminal for 14ga wire that fits these screws would be helpful too. something as high as you can find. . That meant calculating all the way to 32 multiples of a half wave on 10 meters. I won't bore you with all that so the first portion of this still only shows up to the 4th multiple. Tune Around! He had heard good things about 'Balun Designs' so he recommended you. The Nelson antenna 9 to 1 unun did the trick. I sent him the link to the 49:1 unit to get his feedback. for your country and favorite modes of operation. Here they are in order: A few more comments about this 49:1 autotransformer EFHW design. SO-239 (UHF female) chassis mount with screws, nuts, lock washers. (Note: I am not satisfied with this part of the project, so I will describe it here briefly. For instance, to work 40m be sure the antenna is at least Re: 9:1 or 49:1 unun for end-fed long/random wire? (Center fed is so appealing because you avoid this.). Wire lengths for the 4:1 ratio in models 4130, 4132, 4134, 4932 and 4935. (QST, Oct 1926, "The Length of the wire lengths less than 1/4 wavelength of the lowest desired frequency In addition to multiples, /Title (Wire-Lengths-for-9-1-ununs.pdf) /ModDate (D:20221212112042) Alternate connectors and Mounting Options are available in the. , The "Best" Random Wire Antenna Lengths /Count 1 9:1 Unun 1.5-54MHz 2kW 9132S. Start winding the Matching Auto Transformer, each pass through the center of the core equals one turn. Here I show finalizing the antenna, getting it in the air, and run. The 49:1 impedance transformer will help you bring down the high impedance of your resonant EFHW antenna to almost 50 Ohm. Notice from column f that there is no length giving low impendance for << Upon further research, I remade it tightly twisting those two separate wires together, just as it shows in archjeb's picture, and it worked surprisingly well. which got me thinking. 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. Custom mix low permeability ferrite by Fair Rite Products for maximum bandwidth. Drill out holes in the designated bottom of the electrical junction box for the SO239 chassis mount. Humor 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. The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? This article details the construction of the transformer. This homebrew 49:1 impedance transformer is the heart of any EFHW antenna you will build, most of the time. 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. "Just received my new 64131 yesterday and was anxious to see how well it performed. wire is at least 1/4 wavelength. Hi guys,not really hfu related,but I tought I might ask here as I have my account. frequencies for your country or favorite modes. Each vertical blue line represents an amateur radio band. , This is a partial reprint (with permission) of an excellent series of articles published by KV5R Part List: 40-30-20-15m bands for my 4 band Elecraft K1 qrp rig. I used the RigExpert Zoom AA-55 to test VSWR of the 49:1 unun impedance transformer. The length should be calculated based on the lowest frequency to be worked. Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges. >> 27.00 (27.00/Unit) Free Postage. Thanks for your answer,I will probably go with the 9:1 then. This is not exactly a 1/2 wavelength in free space, but works for wire as it has a different velocity factor than "air". var sc_security="1df091cc". 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. Coverutilizes integralneoprene gasket for weatherproof integrity. A so-called random wire antenna is an end fed antenna. While these lengths have been shown to work well on many bands, which <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> 10m or 33' long. 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. 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). If the choices are. , Reprinted with permission of Hamuniverse, this is an excellent explanation of SWR and how to best me Contact See the picture below. In total 29 contacts were made from British Columbia to Texas to Florida in 40 minutes on 20M. a more capable tuner - see AA5TB's NEMA rated 4x marine grade junction box for outdoor installations. 40-30-20-17. However, the list has been revised and is good for wires as long as 500 feet. 33 ft #18 insulated copper wire (20m half wave), Counterpoise: 1 meter coax (0.05 x wavelength) connected between 64131 and Balun Designs 1115d Isolation /Choking balun, 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. Suggested wire lengths for 1-61 MHz operation (measured from Bullet wire point): Bands Covered (meters) Wire Length (feet) Minimum Coax Length (feet) 40-30-20-15. Winding 1:64 Matching Auto Transformer on the FT240-43 core. I'm looking forward to getting off work and hitting 40 & 20 meters again!! [ /PDF /Text /ImageI ] 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. SO-239 connectors are silver plated with Teflon insulation. endobj 74 0 obj <>stream It may not display this or other websites correctly. 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. j#f5(fk0?P[polEo5b2-/oVZu1Qo-I6C/M@TbddPc#cdZZ|7+|o{}!F#?Go7ju|?wwgow/c2/W-m~~hn[S29OU}}r7lc]wsw[shS[#qbrrK[7*0,Xv{k+o {=*vo S__O~*=y/zk75O?yjCnXS{`~Ii'c_GxN. endobj %PDF-1.4 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! Links doing the initial 468/f on C and D scales. stream excellent page for EFHW info - or, addressed below, to cut the wire % If you want a single band portable antenna you can mount pretty much however, look up this design. I only used two screws instead of four. Support The Site (The numbers aboveare a great start, thanks to Jack and Mike! <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Using a 49:1 transformer shoot for the best 50 match @ appx 2450 load over your working frequency bands. 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. 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 Here's a list of recommended lengths of wire to use with a 9:1 unun. The Short Answer Would Be That an UnUn Is a "UN balanced to UN balanced" matching transformer. well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) The length of enamelled copper wire per winding for the T-200-2 powdered iron toroid core is determined by length per winding = 50mm per turn plus 250mm tails. While I have not done so yet, I plan on gluing the test cap to the back of the junction box. You are using an out of date browser. /ColorSpace 11 0 R Designed for those who want the maximum isolation and choking across the full HF spectrum. google_ad_client = "ca-pub-9377297764300878"; bands you're intested in in a vector like the example below, by typing. The magic lengths to use with the End Fed longwire is 29, 35.5, 41, 58, 71 and 84 feet I use a 29 foot wire with my PackTenna 9:1 balun for 40m-10m and then add a 28 foot length for better coverage on 80m when needed. The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. The short piece is for the primary winding of the transformer, and the long piece is for the secondary winding of the transformer. 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). Theme designed by Papathemes. installed, it is a compromise antenna but great for portable use because The unun was floating at about 15 feet above ground. The First Thing New Hams Often Ask:What Is An UnUn? If you want all the bands from /Filter [ /FlateDecode ] I have found this calculation to work well, however it depends on many factors such as wire used, location etc. 3. Antenna Design EFHW unun Resonant Long Wire 49:1 Transformer With 67' Antenna Wire. The graph below shows lengths to avoid for different collections of bands. << Work all bands from 80 through 10 on it. 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. I got three FT240-43 toroids (two would be lighter, but three increases the curie point so it can handle longer duty cycles), a spool of the 14 gauge enameled wire . The QRP End-Fed Half-Wave Antenna 49:1 Transformer Building a great impedance transformer for Ham Radio end-fed wire antennas. 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. This undesired reflection of RF power back toward the transceiver is identified as a high voltage standing wave ratio (VSWR or SWR). /Im0 Do Here is an ARRL 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. These dimensions were derived from modelling the antenna in EZNEC. 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. "I received my third balun from Balun Designs this afternoon. The fewer bands, the fewer high impedance regions to avoid. 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. Random wire lengths you should and should not use! You also want the antenna to be at least 1/4 wavelength long for each band you plan to use. 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. 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. One single wire, no solder connections,very simple.all the way from the tuner to the end support. Just an FYI that I thought you might be interested in. 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 "Super Bullet" End Fed Long Wire Antenna Matcher - 1500/3000 watt rated for Super-Punch of your signal! Then verify it with your installed antenna and SWR measurements. You have to stay away from a half wavelength on any frequency. Solder a the 100pF capacitor between the center conductor wire and ground wires. google_ad_slot = "1982258389"; Ham Radio Videos! Click to enlarge. << <> Cut a 4 foot length of AWG #18 enameled wire. Usually any wire length that is non resonant, like those shown above, will work with the 4:1 ratio. Repeater Basics random wire page. I used 2000 and 1000 ohm resistors in series connected to the proper unun wires with alligator clips for a total of 3000 ohms. Swr usually is all over the place and the tuner will just not do it's job. 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.
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