/CreationDate (D:20221212112042) The Nelson antenna 9 to 1 unun did the trick. q 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). 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 . Electronics 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 have found this calculation to work well, however it depends on many factors such as wire used, location etc. Continue twisting the entire length of the short wire. Usually any wire length that is non resonant on the band or bands desired will work with the 4:1 ratio. /Title (Wire-Lengths-for-9-1-ununs.pdf) something as high as you can find. 22.00 + 5.00 Postage. 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. understand its properties. rig, often with no feedline, and the other end in the air attached to It uses an FT140-43 or FT240-43 toroid in a 49:1 impedance matching unit at the base and a 110 micro Henry (H) coil to act as a loading coil for 80m and a choke to stop higher frequencies using the last 2m of wire. >> 4 0 obj 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. endobj %%EOF Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges. multiples, and of course different band combinations yield different Power handling is 100 watts CW / SSB & 25W Data modes. which got me thinking. 31 %PDF-1.5 Even easier than Q 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. it is easy to pack and easy to install. The Short Answer Would Be That an UnUn Is a UN balanced to UN balancedmatching transformer. Downward impedance transformation by factor of 49. Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. Moving the pot up and down gives a feel for the SWR versus antenna impedance sensitivity. Lengths to avoid are not always the same as Best SWR was . 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 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. Start winding the Matching Auto Transformer, each pass through the center of the core equals one turn. Do what works best! , This is a partial reprint (with permission) of an excellent series of articles published by KV5R Click to enlarge. Post Reviews 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. Antenna Design "Can you please recommend schematics that are designed to tune setups like these? This is a 4:1 Current Balun.That means it can match a 200ohm antenna to a 50 feed line. % The ratio doesn't need to be 49:1 2,400 ohm either, other ratios will transform to other impedance. We hoisted the free end of the antenna wire approximately 30 feet into a tree. DIY 49:1 Unun Impedance Transformer For End-Fed Half Wave (EFWH /ModDate (D:20221212112042) 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA 9:1 or 49:1 unun for end-fed long/random wire? Use a slide rule! and leave the unun on the ground. Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. config file by typing gnuplot rw.gnu. 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. 2 0 obj %PDF-1.4 So for example 80m could range in length from 120 to 133 feet. To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. excellent page for EFHW info - or, addressed below, to cut the wire I used the RigExpert Zoom AA-55 to test VSWR of the 49:1 unun impedance transformer. 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. However, the list has been revised and is good for wires as long as 500 feet. Let the now free end of the short wire hang down from the toroid. This was 9m vertically metres up a fishing pole and then about 5.8m out. Midi Music 3 0 obj The fewer bands, the fewer high impedance regions to avoid. 4 0 obj While I have not done so yet, I plan on gluing the test cap to the back of the junction box. For a better experience, please enable JavaScript in your browser before proceeding. var sc_invisible=1; 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. 8 0 obj these are the worst lengths and you want to be as far from colored 1 0 obj "I received my third balun from Balun Designs this afternoon. End Fed Half Wave Antenna Coupler Schematic - 7-30MHz. Drill a hole in one side for the antenna radiator wire mount (for a #8 bolt in my build). Simple End Fed Half Wave for 40m (and how it works) 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. 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). Here they are in order: Ham Satellites VSWR analysis of the antenna in the field showed that VSWRs between 3-5.5 from 40M to 10M. 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 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. This Balun Designs unit is replacing an MFj 1982 HP EFHW balun that was DOA when it arrived last May. Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) 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. UJM-49-1 $56.99 Save up to 6% when you buy more. 35. In another life, I could have been a telephone engineer. For instance, to work 40m be sure the antenna is at least 10m or 33' long. 3 to31 MHz - up to 1kW intermittent (50% duty cycle). Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. 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!! One is for the top of the box so that it can be hung up. Cut a 4 foot length of AWG #18 enameled wire. google_ad_client = "ca-pub-9377297764300878"; 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. Just add or subtract as needed a little at a time to get the best compromise. The transformer usually used with an end fed wire is a 9:1 transformer. At multiples of half wavelengths of the 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. . 9:1 Unun 1.5-54MHz 2kW 9132S. so that it is not a halfwave multiple of any frequency you want to use. Recommended wire lengths for Unun Balun - Webclass.org End Fed Half Wave 40-10 Wire Antenna - N6DOZ The counterpoise wire does not have to be similar in length to the main radiator wire and just a short wire is all that is needed, about 0.05 . HF Underground wiki Radio Hobbyist technical blogHFU Discord EuroPirate ChatPropagation DataTeamspeak Server, TDK CXA-2090 LCD Inverter Module New Old Stock USA Seller $19.99, Shortwave Pirate Radio In North America And Around The World, And Other Signals That Go Bump In The Night, Login with username, password and session length. /ProcSet 7 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. /BitsPerComponent 8 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. V#X~[Z?\ZcX:-Y?&Y?IqTnayZ{jTZOub}=UTWu1G>o.,RaT c=W>:sECXTkc=X /Length 6 0 R Notice from column f that there is no length giving low impendance for A png image named g.png will be created. A standard recommendation (see QST, March 1936, p. 32, "An Unorthodox the program as I did, above, for my K1. I imported my spools from the US, but I have seen them on Ebay in the UK. [ /PDF /Text /ImageI ] Ultimately, this housing works fine, but it is heavy and clunky.). google_ad_width = 160; "The Simple Build" 64:1 EFHW antenna transformer (UnUn) 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. Superglue 2 toroids together. He was so impressed that he purchased a 9:1 unit from you, his will be delivered Saturday. SBULLET-9U-1500. JC[ d8O[UKKQ{yZ{G 'Upno_*~8uo a@G`' zxUHXW&`}mEp`?i0 oE:N0-/t"t.-? for your country and favorite modes of operation. Re: 49:1 transformer for EFHW antenna - groups.io stream /Type /XObject You can add your own wire or get the complete product from this link EFLW-3K antennas. <> 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. We are working every day to make sure our community is the best Radio Hobbyist's site. << The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? Ham Radio News! <> /Im0 Do I plotted the results for the U.S. CW band edges for use with my4 band Elecraft K1 qrp rig. End fed 49:1 60ft wire (using coax as the counter poise. Cut the antenna radiator wire (free untwisted end of long wire) of the unun to the correct size, scrape the enamel insulation off of the free end with a box cutter, add a ring terminal, and secure to antenna radiator bolt with washers and lock washers. /Resources << 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. 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 . What Is an End-Fed Half-Wave (EFHW) Antenna? - OnAllBands When used with the stated lengths shown in thetable below, the 9:1 ratio will Based on the success of our model 4932, this 5kWconfigurationisalso perfect for matching both long and short length wire antennas for multiband use. The other is to provide strain relief for the antenna wire). Each winding is counted when the wire enters through the center hole of the toroid. Cannon". Random wire length for 9:1 unun - fairlawnarc.groups.io 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? Tune Around! Clansman End Fed Long Wire Antenna Used. 3 0 obj 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. I won't bore you with all that so the first portion of this still only shows up to the 4th multiple. W3EDP's results in the above referenced End Fed Half Wave Wire Antennas | N6CC So for example 80m could range in length from 120 to 133 feet. 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. The following wire connections do not need to be made in the order I described. SO-239 connectors are silver plated with Teflon insulation. tuner the colored bands below are the best lengths as long as your x[q;`&z`uAlo#V@;hvOYt, @*Ys~_W_~W_aw_ p[N+}[t-^oLy}xz>7/~c|ZZt75;kN^=>Y+_~|b~"m*tw>xG=x6Qwz|xvz- This unit is a Balun Designs, in collaboration with Fair Rite products, has developed what we consider to be the best single core 1:1 feedline isolation balun available today. ), Note that Jack, VE3EED,went SK several years agohe will be missed. A good place to start is the formula 468 / f (MHz) for a 1/2 wavelength wire antenna. It is important to use a counterpoise. LDG Electronics RU-9:1 Unun RU-9-1 - DX Engineering This homebrew 49:1 impedance transformer is the heart of any EFHW antenna you will build, most of the time. (Also check out AB3AP'Swebsite and say thanks for sharing his skills. PDF shortened multi-band End-Fed Half Wave (EFHW) antenna for 80-10m While these lengths have been shown to work well on many bands, which June 8, 2022 at 9:17 am. =======================, More on Random Wire Lengths from Mike, AB3AP (06-29-2012), I was surfing around Hamuniverse.com and found thIs page on random wire antennas: In stock . Drill out holes in the designated bottom of the electrical junction box for the SO239 chassis mount. Balun One Nine v1 - Tiny Low-Cost 1:9 HF Antenna Balun and Unun with Single Wire/End Fed Antenna - K7MEM a more capable tuner - see AA5TB's 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. Power Handling (CW/SSB): 100 W/200 W Enclosure Width: 2.500 in. /Type /Catalog 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. Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 1500 Watts, End Fed Antennas &nb If you want all the bands from x 2 in. >> 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. . That meant calculating all the way to 32 multiples of a half wave on 10 meters. (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. 0$Ve high the other 1.5m (4.5feet). /Length 10 0 R Lengths for Long-wire Antennas Jack - VE3EED Recommended lengths: 29 - 35.5 - 41 - 58 - 71 - 84 - 107 - 119 - 148 - 203 - 347 - 407 - 423 Not recommended lengths: 16 - 19 - 22 - 26 - 32 - 33 - 38 - 44 - 46 - 48 - 52 - 64 - 65 - 66 - 76 https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/.