IMG_2.jpg Step 2: Take the 6 feet of 18 gauge enameled copper wire, measure 11" from one end and fold it back. To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. (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. 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. Lengths of a half-wave or multiple must be avoided. End Fed Half Wave Antenna Coupler Schematic - 7-30MHz. Power Handling (CW/SSB): 100 W/200 W Enclosure Width: 2.500 in. EFHW unun Resonant Long Wire 49:1 Transformer With BNC or SO-239 | Mobile Phones & Communication, Radio Communication Equipment, Antennas | eBay! This Balun Designs unit is replacing an MFj 1982 HP EFHW balun that was DOA when it arrived last May. 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] /Type /Pages For example, This is not exactly a 1/2 wavelength in free space, but works for wire as it has a different velocity factor than "air". x@ Computer Help 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. Hopefully these random wire length calculations will help us all make this "easy" antenna work better! Ask Elmer 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. You can add your own wire or get the complete product from this link EFLW-3K antennas. We are working every day to make sure our community is the best Radio Hobbyist's site. 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. Odds are that most lengths are fine though, so the easiest solution is to pick a length based on something else (like, the room you have available) and if you get unlucky, roll the dice again. Here's a list of recommended lengths of wire to use with a 9:1 unun. are blocked out because an antenna should be at least that long. Windings are inserted into Teflon tubes increasingtotal breakdown to 10,000 volts. This project assembles a 49:1 ferrite-core ("FT") type #43 transformer that matches 50 ohm input to 2500 ohm end fed antenna. /Length 6 0 R So for 80 meters (say 3.525 MHz) this gives you about 133' of wire. 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. >> q So I just wanna say thank-you!! Hope it's clear now, if not. Q A 50 foot run of RG-8X coax connected the antenna into the LDG Z100-plus tuner and then a Yaesu FT-891A transceiver. , Most matching problems occur when the antenna system 1936 article, however, fall in line with 468/f and so is used here. . 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). 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 . 49:1 UNUN IMPEDANCE XFORMER FOR END FED HALF WAVE ANTENNA. Cut a 4 foot length of AWG #18 enameled wire. Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. You can get good loading and low swr on sometimes 2 or 3 bands, but one or more of the bands thatyou want, just will not cooperate with an swr that can be adjusted with the "tuner". this So for example 80m could range in length from 120 to 133 feet. Humor Be sure to review the various lengths in the link below to obtain the lowest SWR across most if not all HF bands. are easily converted to half wavelengths by the famous 468/f generally I imported my spools from the US, but I have seen them on Ebay in the UK. When on the trail, at Field Day, or whenever a good antenna is The trick, therefore, is either We have also installed an additionalstud which can be used for a separate counterpoise wire rather than forcing the use of the feedline's coax shield. , Reprinted with permission of Hamuniverse, this is an excellent explanation of SWR and how to best me rig, often with no feedline, and the other end in the air attached to Theme designed by Papathemes. Hertz Antenna" shows in line 2 of the table that a similarly installed This transformer is designed to be used with an end fed half wavelength of wire only. var sc_security="1df091cc". Enclosure Depth: 1.250 in. (Also check out AB3AP'Swebsite and say thanks for sharing his skills. 9:1 Unun 1.5-54MHz 2kW 9132S. Thanks for your answer,I will probably go with the 9:1 then. Reading Room and experiment. 35-45, 54-64, 67-77. doing the initial 468/f on C and D scales. 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. June 8, 2022 at 9:17 am. So those are the numbers above thatwe have to stay as far away from as possible when building a long-wire antenna. 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. A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. used by hams for dipole lengths. My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . <> A small ring terminal for 14ga wire that fits these screws would be helpful too. N4UJW. Designed for use with single wire unbalanced antennas, this new addition is small, compact and perfect for quick portable/emergency installations. HF & Shortwave 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). Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. It will be good for 15m, and 10m. 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. high the other 1.5m (4.5feet). Use a slide rule! 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. I only used two screws instead of four. In total 29 contacts were made from British Columbia to Texas to Florida in 40 minutes on 20M. 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? (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. For those that enjoy the LNR and Hy Endfed antennas, but want to run more power, Balun Designs now offers an excellent alternative. X:nzf4p:t;r }~_HOZcX:^$* J^XZuu|"nX/Wkw0hA>y1(z2+v_Xzu[/:^$*m*>hk_:+c{ After winding #2 is made and extends down the backside of the toroid, untwist the wires. excellent page for EFHW info - or, addressed below, to cut the wire it is easy to pack and easy to install. Even easier than 25 0 obj <> endobj endobj Use only the white gaps for your antenna lengths, and if 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. 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). Tune Around! Jack, VE3EED - SK. Save program output in file named 'f', and use | UJM-49-1 $56.99 Save up to 6% when you buy more. Site Map /BitsPerComponent 8 Ham Radio News! << I wrote a small C program that does just what Jack did, butI used the band edges. 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. V#X~[Z?\ZcX:-Y?&Y?IqTnayZ{jTZOub}=UTWu1G>o.,RaT c=W>:sECXTkc=X 9:1 UnUn End Fed Long Wire Lengths - Pretty Simple. . stream Then verify it with your installed antenna and SWR measurements. The following wire connections do not need to be made in the order I described. all US ham bands. The table below represents half wave lengths and multiples that you DO NOT WANT TO USE! transmit frequency the impedance is so high that tuners in most rigs In fact, the 9:1 unun that I built is actually an autotransformer. Placing 3000 to 4000 ohms of resistance between the free end of the twisted portion of wires (the gound) and the free end of the long wire (the wire that connects with the antenna radiator after the 14th winding), can simulate adding an antenna radiator wire to the unun impedance transformer. This transformer converts the impedance at the end . Do what works best! Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. answers on D - one setting. Theme: Newsup by Themeansar. AndWhat Is It Used For In Antennas? 73, 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. For a better experience, please enable JavaScript in your browser before proceeding. Designed for those who want the maximum isolation and choking across the full HF spectrum. Here they are in order: 80m up, W3EDP's 84' antenna, 17' counterpoise is probably the way to go. >> Again, the bands are USA, so change 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 Several ways exist to bring the wire's high impedance feedpoint closer to the desired 50 ohms, including use of a 49:1 or 64:1 unun, which eliminates the need . 2 eyehooks with washers and nuts (I used #8 diameter, but size is up to you.) <>/Metadata 239 0 R/ViewerPreferences 240 0 R>> 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. 73. JACK, VE3EED 8 0 obj Feeling a bit too lazy to calculate that by hand, however, I wrote a endobj /Contents 5 0 R 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. In another life, I could have been a telephone engineer. (A t0 B) Fold over 6 to 8 inches and twist it together. wire lengths less than 1/4 wavelength of the lowest desired frequency At this point, Ive only used the 49:1 tap, but plan to take the 64131 whenever I operate portable. So is an essential piece of gear to have. So for example 80m could range in length from 120 to 133 feet. 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. We recently found some good information about random wire lengths that you should and should not use. Code Practice which got me thinking. 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. Shortwave Listening SWR was good after cutting the wire to appropriate length. Superior Essex Heavy build polyamideimide. Wait a few minutes for glue to set. 7 0 obj 2. The fewer bands, the fewer high impedance regions to avoid. 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. These dimensions were derived from modelling the antenna in EZNEC. Note: My (A to B) length was 6 inches. One single wire, no solder connections,very simple.all the way from the tuner to the end support. I won't bore you with all that so the first portion of this still only shows up to the 4th multiple. This homebrew 49:1 impedance transformer is the heart of any EFHW antenna you will build, most of the time. Antenna") is an 84' long end fed and a 17' long counterpoise (6.5' for 20m). understand its properties. EFHW unun Resonant Long Wire 49:1 Transformer With 67' Antenna Wire. The most important length is one that is non-resonant on any band. Privacy Policy STORE 40-30-20-15m bands for my 4 band Elecraft K1 qrp rig. 49:1 End Fed Half Wave Antenna 40-10M 100W Version Bands of operation 40,20,15 & 10m using 67 feet of our UV, Ozone resistant Antenna wire. A level of 500-600 watts is the maximum with a further reduction onany band measuringabove 3:1. Cannon". Here Is a 250 Watt Home-Brew That I Made In about an Hour. A way of connecting the analyzer to the transformer. << 5 0 obj well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) /* Ad banner 160 x 600 */ It's an efficient way to get all the multiples Picture Information. The vertical (y-) axis shows the VSWR and the horizontal (x-) axis shows the frequencies. Make sure the beginning few inches of twisted wire is not involved in the winding (i.e., just hanging down from the toroid). I'm consistently pleased with the quality and ease of use of Balun Designs products and look forward to my next purchase in the future. See the picture below. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. The key is you want to stay at least 1/2w long but not near 3/4w for any band of interest. 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 . is that for a given ham band there are min and max frequencies which 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. Antenna Design You can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. CQ-Calling All Hams! 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. 4 0 obj The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. x 2 in. Clansman End Fed Long Wire Antenna Used. 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 choices are. This design is excellent for matching both long and short length wire antennas for multiband use. Experimenting by slightly changing the wire length (+ or-) is encouraged to provide best overall performance. Some of these numbers are too close to squeeze in between them. Just add or subtract as needed a little at a time to get the best compromise. JavaScript is disabled. 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. K1S Valentines Are (Almost) Out The Door! %%EOF /Count 1 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. and leave the unun on the ground. You are using an out of date browser. $119.95. , This is a partial reprint (with permission) of an excellent series of articles published by KV5R 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. At multiples of half wavelengths of the 4 x 4 x 2 electrical junction box (available at big box hardware stores), One PVC DWV Test Cap (available at big box hardware stores in plumbing). 74 0 obj <>stream endobj