The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. There probably should be some holes for ventilation. . That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . 9:1 or 49:1 unun for end-fed long/random wire? 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. 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. Here I show finalizing the antenna, getting it in the air, and run. Code Practice The following wire connections do not need to be made in the order I described. presents an extremely high impedance to the tu Again, the bands are USA, so change them Continue on winding the long wire through the toroid to complete loops 3 through 14 as shown in the schematic below. This project assembles a 49:1 ferrite-core ("FT") type #43 transformer that matches 50 ohm input to 2500 ohm end fed antenna. 9:1 UnUn End Fed Long Wire Lengths - Pretty Simple. The major point of this message is to tell you that approximately 20 minutes after I connected the balun unit to the antenna, I made contact with a gentleman in Italy-my first European contact!! . 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. 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. Even better would be shortening to 53'. For those that enjoy the LNR and Hy Endfed antennas, but want to run more power, Balun Designs now offers an excellent alternative. Power handling is 100 watts CW / SSB & 25W Data modes. << high the other 1.5m (4.5feet). 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 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. The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. 40-10m with a 49:1 Unun. endobj Be sure to review the various lengths in the link below to obtain the lowest SWR across most if not all HF bands. A so-called random wire antenna is an end fed antenna. Note: My (A to B) length was 6 inches. See the picture below. 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 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. In the first year using this unun with a random length endfed wire (Aluminum Elec fence wire at that) I managed to confirm WAS via LoTW on 10m, 15, 17, 20, 30, 40, 80. . We are working every day to make sure our community is the best Radio Hobbyist's site. About Batteries (Originally published February 22, 2021). 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. Best SWR was . 2 0 obj The idea 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. I used a homemade jig made of an SO239 chassis mount to bare wires, alligator clips, and a coax-jumper with PL259 (UHF male) ends; see picture below. I purchased a MFJ-16010 Random Wire Tuner and an LDG RU 1:1 unun. In another life, I could have been a telephone engineer. 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. 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. 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. The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. I used 2000 and 1000 ohm resistors in series connected to the proper unun wires with alligator clips for a total of 3000 ohms. (The numbers aboveare a great start, thanks to Jack and Mike! End Fed Half Wave Antenna Coupler Schematic - 7-30MHz. %PDF-1.4 1 0 obj $1YacO5Q}YC\>qZ } Twist the short and long wires together starting at an end of each wire. I imported my spools from the US, but I have seen them on Ebay in the UK. I did not want to put the transformer in the housing until I tested it. Both were on 20 meters at 97 watts, Icom 7300. x 2 in. Enclosure Depth: 1.250 in. 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. I connected the free untwisted end of the short wire to the center conductor of my homemade testing jig (see tools list) with an alligator clip. This transformer is designed to be used with an end fed half wavelength of wire only. A Balun is used to match a balanced line to an unbalanced line. endobj Here's a list of recommended lengths of wire to use with a 9:1 unun. endstream Hopefully these random wire length calculations will help us all make this "easy" antenna work better! are easily converted to half wavelengths by the famous 468/f generally I have found this calculation to work well, however it depends on many factors such as wire used, location etc. /ColorSpace 11 0 R Wire lengths for the 4:1 ratio in models 4932 and 4935. I sent him the link to the 49:1 unit to get his feedback. endobj /Type /Catalog used by hams for dipole lengths. The short piece is for the primary winding of the transformer, and the long piece is for the secondary winding of the transformer. 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. <>/Metadata 239 0 R/ViewerPreferences 240 0 R>> 49:1 UNUN IMPEDANCE XFORMER FOR END FED HALF WAVE ANTENNA. &nb 35-45, 54-64, 67-77. AndWhat Is It Used For In Antennas? The First Thing New Hams Often Ask:What Is An UnUn? hbbd```b``^ "Cs;D2 I*`0D;+EVUHy`qml0{YVw`b0i DvkAh |"w I2% ?W%@Fg`` 6 For instance, to work 40m be sure the antenna is at least 10m or 33' long. /Contents 5 0 R Coverutilizes integralneoprene gasket for weatherproof integrity. The 30 day return period lapsed before I could get the antenna deployed to test it. Drill another hole in the same side as the antenna radiator wire mount hole. 4 0 obj 9:1 Unun 1.5-54MHz 2kW 9132S. 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. 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. wire is at least 1/4 wavelength. You'll want to have that wire up as high as you can get.. The fewer bands, the fewer high impedance regions to avoid. << endobj Quantity: Sold individually. Well, I didn't think it would make any difference at that many multiples. 32.00. For instance, to work 40m be sure the antenna is at least <> At multiples of half wavelengths of the Advertising Info The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Q 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). The length should be calculated based on the lowest frequency to be worked. The most important length is one that is non-resonant on any band. 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. (A t0 B) Fold over 6 to 8 inches and twist it together. Notice from column f that there is no length giving low impendance for I swept the VSWR of the unun and resistors as described from <1 to 55MHz. Product Reviews The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. Antenna") is an 84' long end fed and a 17' long counterpoise (6.5' for 20m). , This is a partial reprint (with permission) of an excellent series of articles published by KV5R google_ad_height = 600; 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. It will be good for 15m, and 10m. Free Postage. 10m or 33' long. He had heard good things about 'Balun Designs' so he recommended you. N4UJW. 8 0 obj Using a 49:1 transformer shoot for the best 50 match @ appx 2450 load over your working frequency bands. 1 0 obj This transformer is designed to be used with an end fed half wavelength of wire only. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. >> Figure 3 Wiring of the 9:1 voltage unun. You need to use these lengths and the longer ones . Power Handling (CW/SSB): 100 W/200 W Enclosure Width: 2.500 in. 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. 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. 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. I included the tools I used to analyze the transformer as well; this is only necessary if you are interested in analyzing your project. Turns 1 & 2 are primary windings (the short wire). This type of antenna is very easy to install because there is no need . Continue twisting the entire length of the short wire. Having the option to switch rapidly between 49:1 and 64:1 should prove to be a really nice feature.. A level of 500-600 watts is the maximum with a further reduction onany band measuringabove 3:1. Ham Radio Videos! /Pages 3 0 R I have included a screenshot showing the stations that reported spotting my 200 mw beacon over the last 16 hours. 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. 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.). FCC Information 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. 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. I used the RigExpert Zoom AA-55 to test VSWR of the 49:1 unun impedance transformer. SSTV 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. I only used two screws instead of four. config file by typing gnuplot rw.gnu. Just add or subtract as needed a little at a time to get the best compromise. In fact, the 9:1 unun that I built is actually an autotransformer. 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. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. The length of a half wave antenna is calculated using the following formula: L (ft) = 468 / f (freq in mhz). EFHW unun Resonant Long Wire 49:1 Transformer With 67' Antenna Wire. and experiment. 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.). Here Is a 250 Watt Home-Brew That I Made In about an Hour. An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). The transformer usually used with an end fed wire is a 9:1 transformer. Experimenting by slightly changing the wire length (+ or-) is encouraged to provide best overall performance. endobj 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. 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. UJM-49-1 $56.99 Save up to 6% when you buy more. Even easier than It may not display this or other websites correctly. SEARCH