. Then verify it with your installed antenna and SWR measurements. 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. Longer wire is always more 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. I'll get a 9:1 unun,and use a suggested random wire length to avoid half-wave and it's multiples then,that sounds like the best things I can get out of this setup. 6 0 obj endstream endobj startxref One end goes straight into the 9:1 Unun 1.5-54MHz 2kW 9132S. VSWR analysis of the antenna in the field showed that VSWRs between 3-5.5 from 40M to 10M. Code Practice stream So is an essential piece of gear to have. 80m up, W3EDP's 84' antenna, 17' counterpoise is probably the way to go. >> Work all bands from 80 through 10 on it. Power Handling (CW/SSB): 100 W/200 W Enclosure Width: 2.500 in. To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. 40-30-20-15m bands for my 4 band Elecraft K1 qrp rig. /Pages 3 0 R That meant calculating all the way to 32 multiples of a half wave on 10 meters. Presented for your consideration by Jack, VE3EED. He had heard good things about 'Balun Designs' so he recommended you. << The Short Answer Would Be That an UnUn Is a "UN balanced to UN balanced" matching transformer. InJack's own words. 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. 35. well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) I connected the free twisted end of the short and long wires (the ground) the chassis wire (ground) of my homemade testing jig with alligator clip. endobj Wire lengths for the 4:1 ratio in models 4130, 4132, 4134, 4932 and 4935. Antenna") is an 84' long end fed and a 17' long counterpoise (6.5' for 20m). Performance is ASTOUNDING, far exceeding my expectations. 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). So a 49:1 impedance transformer is needed to match the 50 ohms of the coax at the feed line. it is easy to pack and easy to install. stream The Short Answer Would Be That an UnUn Is a UN balanced to UN balancedmatching transformer. 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. For instance, to work 40m be sure the antenna is at least So for 80 meters (say 3.525 MHz) this gives you about 133' of wire. Usually any wire length that is non resonant on the band or bands desired will work with the 4:1 ratio. /Height 752 presents an extremely high impedance to the tu /Count 1 If you plan on stringing up a dipole you use 2 equal lengths of wire with the Balun in the middle. Picture Information. Change the program to use 423 if desired.) Box cutter (for scraping enamel off of wire ends), (Helpful) Step drill bit for SO-239 connector, Paracord (for simulating and measuring lengths of windings on toroid), Antenna analyzer for HF frequencies (I use the RigExpert Zoom AA-55), Resistor(s) totaling about 3000 ohms (I used 1K and 2K ohm resistors in series). 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. I plotted the results for the U.S. CW band edges for use with my4 band Elecraft K1 qrp rig. here are values for CW portions of the USA 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. For example, 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? 2 0 obj Links Thanks for your answer,I will probably go with the 9:1 then. %PDF-1.5 % 4 0 obj . Superior Essex Heavy build polyamideimide. understand its properties. About Batteries That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . 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. The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. 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. Proudly powered by WordPress 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. 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. Thus a 1/4 wave for 20m@16ft, 40m@33ft as examples are not going to work. Drill another hole in the same side as the antenna radiator wire mount hole. /Width 748 <> HF & Shortwave License Study Cut the center conductor wire (free untwisted end of short wire) of the unun to the correct size, scrape the enamel insulation off of the free end with a box cutter, and solder it to the SO239 connector. endobj . This is the latest and greatest transformer design for End Fed Half Wave (EFHW) antennas. Some of these numbers are too close to squeeze in between them. <> 73. JACK, VE3EED SO-239 (UHF female) chassis mount with screws, nuts, lock washers. endobj 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. We are working every day to make sure our community is the best Radio Hobbyist's site. google_ad_client = "ca-pub-9377297764300878"; The table below represents half wave lengths and multiples that you DO NOT WANT TO USE! You need to use these lengths and the longer ones . the program as I did, above, for my K1. want the antenna to be at least 1/4 wavelength long for each band you Alternate connectors and Mounting Options are available in the. Repeater Basics 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 these are the worst lengths and you want to be as far from colored The length should be calculated based on the lowest frequency to be worked. In addition to multiples, BUILD INSTRUCTIONS FOR 49:1 UNUN IMPEDEDENCE TRANSFORMER: WX1MAR and I brought the DIY 49:1 unun with a borrowed antenna radiator wire cut for 20M half-wavelength to Ashland State Park K-2417 in Massachusetts for a Parks-on-the-Air (POTA) activation. >> Here are the final numbers (in my opinion) in green below that would be good for a long-wire antenna: (You may want to make a note of them), REVISED: 29 35.5 41 58 71 84 107 119 148 203 347 407 423, REVISION NOTE: We had a note from James, KB5YN, pointing out that one of my so-called GOOD numbers was 220 feet. 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. (Center fed is so appealing because you avoid this.). 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. Cannon". SEARCH You also 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. 32.00. 1 bolt for antenna hook up (with nuts, washers, lock washers, and possibly thumb screw; I used #8 diameter, about an inch or so in length.). Ask Elmer 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. 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. Quantity: Sold individually. unavailable, a random wire can save the day, but it is important to google_ad_width = 160; used by hams for dipole lengths. AndWhat Is It Used For In Antennas? high the other 1.5m (4.5feet). I purchased a MFJ-16010 Random Wire Tuner and an LDG RU 1:1 unun. thank you. 7 0 obj 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 . Modify bands and Tools 22.00 + 5.00 Postage. 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. Make sure the beginning few inches of twisted wire is not involved in the winding (i.e., just hanging down from the toroid). /Length 6 0 R , Reprinted with permission of Hamuniverse, this is an excellent explanation of SWR and how to best me This calculates to 4.2 m or 14 ft for an 80m end-fed. 35-45, 54-64, 67-77. There are so many new frequencies to stay away from, that it gets pretty tricky for the longer wires. <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> 35. Moving the pot up and down gives a feel for the SWR versus antenna impedance sensitivity. The WorldwideDX Radio Forum was originally established in 2001. For instance, to work 40m be sure the antenna is at least 10m or 33' long. This design is excellent for matching both long and short length wire antennas for multiband use. 31 When you're antenna (or radial) length's an odd multiple of the operating freq, you may not need a balun or even a transmatch. . 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. 35-43, 49-63, 70-85. A 50 foot run of RG-8X coax connected the antenna into the LDG Z100-plus tuner and then a Yaesu FT-891A transceiver. Feeling a bit too lazy to calculate that by hand, however, I wrote a 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. Hertz Antenna" shows in line 2 of the table that a similarly installed 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. This is a followup video to #344 where I assembled the 49:1 UNUN kit from HF-Kits / ARRL. Lowest Band of Operation: 160 meters Highest Band of Operation: 10 meters Additional Information LDG Electronics RU-9:1 Unun
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