I did not want to put the transformer in the housing until I tested it. END FED "RANDOM WIRE" HF DIPOLE 9:1 ANTENNA RELACEMENT ELEMENT ONLY $28.99 Save up to 6% when you buy more. I only used two screws instead of four. 22.00 + 5.00 Postage. Humor https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. I imported my spools from the US, but I have seen them on Ebay in the UK. Electronics endobj I took a literally random length of 14 gauge house wire and attached a banana plug to be shoved into the antenna port of the tuner. "Just received my new 64131 yesterday and was anxious to see how well it performed. SO-239 (UHF female) chassis mount with screws, nuts, lock washers. 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 . (Also check out AB3AP'Swebsite and say thanks for sharing his skills. 40-30-20-15m bands for my 4 band Elecraft K1 qrp rig. K1S Valentines Are (Almost) Out The Door! While these lengths have been shown to work well on many bands, which In addition to multiples, PVC Junction Box(Home Depot), 1 x 1/2 in. these are the worst lengths and you want to be as far from colored Swr usually is all over the place and the tuner will just not do it's job. , Most matching problems occur when the antenna system You have to give up a band or two, like 60m and 6m, as I have found this calculation to work well, however it depends on many factors such as wire used, location etc. for your country and favorite modes of operation. Here I show finalizing the antenna, getting it in the air, and run. 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. << /XObject << /Im0 9 0 R >> (Note: I am not satisfied with this part of the project, so I will describe it here briefly. doing the initial 468/f on C and D scales. 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". Wait a few minutes for glue to set. Beginning from the 3rd band from the left, the vertical blue lines are: 160M, 80M, 60M, 40M, 30M, 20M, 17M, 15M, 12M, (11M), and 10M bands. I included the tools I used to analyze the transformer as well; this is only necessary if you are interested in analyzing your project. x {avla[g#+yt]Mk"B` xp[AO8;c=\b}|8p4cSmzgU7be,+i5ci6uq.x T/s@9uk-oZX;u`=U >8rsIXW B:uUVr6a] The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? /Length 6 0 R Be sure to review the various lengths in the link below to obtain the lowest SWR across most if not all HF bands. Care to buy us a beer? 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. I purchased a MFJ-16010 Random Wire Tuner and an LDG RU 1:1 unun. . Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. The Short Answer Would Be That an UnUn Is a "UN balanced to UN balanced" matching transformer. Reading Room hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r Designed for those who want the maximum isolation and choking across the full HF spectrum. . This calculates to 4.2 m or 14 ft for an 80m end-fed. [ /PDF /Text /ImageI ] 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. For instance, to work 40m be sure the antenna is at least 10m or 33' long. Site Map For calculating the length of a half wave in metres, I use 141 (MHz) for wire elements. I connected it to a 33 wire running from my balcony, through the trees, and ran WSPR overnight to check things out. NOTE: Rewording the previous paragraph, if you have a capable enough . %PDF-1.5 the C code, in Matlab or Octave get a plot by simply putting the I wrote a small C program that does just what Jack did, butI used the band edges. Support The Site /Name /Im0 . program or two to do all the dirty work. >> Wire lengths for the 4:1 ratio in models 4932 and 4935. Theme: Newsup by Themeansar. endobj Balun Designs. My homemade 49:1 EFWH with a 60 wire (cut for 40M) would do just fine! 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. Ask Elmer One is for the top of the box so that it can be hung up. This is the latest and greatest transformer design for End Fed Half Wave (EFHW) antennas. X:nzf4p:t;r }~_HOZcX:^$* J^XZuu|"nX/Wkw0hA>y1(z2+v_Xzu[/:^$*m*>hk_:+c{ Just an FYI that I thought you might be interested in. These dimensions were derived from modelling the antenna in EZNEC. /MediaBox [0 0 748 752] Placing 3000 to 4000 ohms of resistance between the free end of the twisted portion of wires (the gound) and the free end of the long wire (the wire that connects with the antenna radiator after the 14th winding), can simulate adding an antenna radiator wire to the unun impedance transformer. Advertising Info The graph below shows lengths to avoid for different collections of bands. So those are the numbers above thatwe have to stay as far away from as possible when building a long-wire antenna. That meant calculating all the way to 32 multiples of a half wave on 10 meters. Antenna Design The graph below shows lengths to avoid for different collections of bands. It is used for non-resonant verticals like 43 foot or 33 foot Or Wire antennas like an End-Fed 1/2 Wave Multiple Length Wire Antenna. Longer wire is always more Presented for your consideration by Jack, VE3EED. << are blocked out because an antenna should be at least that long. stream The WorldwideDX Radio Forum was originally established in 2001. /Title (Wire-Lengths-for-9-1-ununs.pdf) Usually any wire length that is non resonant, like those shown above, will work with the 4:1 ratio. endobj Use with other lengths can potentially damage the transformer depending on power level in use. endobj 0$Ve frequencies for your country or favorite modes. There are numerous configurations available online that will accomplish this on multiple bands (Google search "end fed half wave antennas"). We'd really appreciate it! google_ad_client = "ca-pub-9377297764300878"; endobj results. The WSPR map is so dense it looks like the US and Europe are just big blobs of color. Using a 49:1 transformer shoot for the best 50 match @ appx 2450 load over your working frequency bands. 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. We hoisted the free end of the antenna wire approximately 30 feet into a tree. So for example 80m could range in length from 120 to 133 feet. endstream endobj startxref 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. Continue on winding the long wire through the toroid to complete loops 3 through 14 as shown in the schematic below. wire lengths less than 1/4 wavelength of the lowest desired frequency <> This undesired reflection of RF power back toward the transceiver is identified as a high voltage standing wave ratio (VSWR or SWR). Here Is a 250 Watt Home-Brew That I Made In about an Hour. rig, often with no feedline, and the other end in the air attached to 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 fewer bands, the fewer high impedance regions to avoid. I have included a screenshot showing the stations that reported spotting my 200 mw beacon over the last 16 hours. so that it is not a halfwave multiple of any frequency you want to use. /CreationDate (D:20221212112042) I'm looking forward to getting off work and hitting 40 & 20 meters again!! Thus a 1/4 wave for 20m@16ft, 40m@33ft as examples are not going to work. Lowest Band of Operation: 160 meters Highest Band of Operation: 10 meters Additional Information LDG Electronics RU-9:1 Unun 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. Contact The "Super Bullet" End Fed Long Wire Antenna Matcher - 1500/3000 watt rated for Super-Punch of your signal! One end goes straight into the 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). << A 9:1 matches 50 ohms to 450 ohms and that turns out to be an ok compromise for feeding 50-100ft of wire for general purpose SW receive. 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. Figure 3 Wiring of the 9:1 voltage unun. This will be for an eyehook in order to provide strain relief for the radiator wire. Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges. 35-43, 49-63, 70-85. Antenna") is an 84' long end fed and a 17' long counterpoise (6.5' for 20m). Here Is a 250 Watt Home-Brew That I Made In about an Hour. Turns 1 & 2 are primary windings (the short wire). Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. here are values for CW portions of the USA The bandwidth where SWR was below 2:1 was about one MHz. 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!! Let the now free end of the short wire hang down from the toroid. 4 0 obj So is an essential piece of gear to have. 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 After winding #2 is made and extends down the backside of the toroid, untwist the wires. To summarise the results WRT to reference antenna consisting of 30ft wire vertical fed with auto- UJM-49-1 $56.99 Save up to 6% when you buy more. 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. It may not display this or other websites correctly. answers on D - one setting. 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. endstream which got me thinking. 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. %PDF-1.7 Jack, VE3EED, hopefully has solved a major headache we all have when we attempt to go thru the trial and error and frustration with getting the random wire to work where WE want it to work. The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. I say run what you got and don't worry about it. 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 Save program output in file named 'f', and use The 9:1 may work best with that length wire and a tuner, but some say that length is undesirable for the hf HAM bands. "I received my third balun from Balun Designs this afternoon. When do you use a 1:1, 9:1 or a 49:1 balun? Here's a list of recommended lengths of wire to use with a 9:1 unun. I made one without doing this and it didn't work so well. This is a followup video to #344 where I assembled the 49:1 UNUN kit from HF-Kits / ARRL. The key to end fed antenna success is the matching network interface between the long wire antenna and the coax feed line and feed line choke at the transceiver. 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. Experimenting by slightly changing the wire length (+ or-) is encouraged to provide best overall performance. In fact, the 9:1 unun that I built is actually an autotransformer. Update guys:made the unun,the antenna was extended to about 37m length,and I added a counterpoise which is about 10m.The whole thing is much higher in the air,compared to where it was before. I used 2000 and 1000 ohm resistors in series connected to the proper unun wires with alligator clips for a total of 3000 ohms. stream /Length 10 0 R Turns 1 through 14 are secondary windings (the long wire). (Center fed is so appealing because you avoid this.). /Width 748 Shortwave Listening This is a 4:1 Current Balun.That means it can match a 200ohm antenna to a 50 feed line. Generally an EFHW will be in the range of 2,000 to 5,000 ohms at the very end of the dipole when resonant. Downward impedance transformation by factor of 49. random wire should use 423/f. 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. 20/40/17m. 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. For a better experience, please enable JavaScript in your browser before proceeding. A png image named g.png will be created. You also want the antenna to be at least 1/4 wavelength long for each band you plan to use. 2 eyehooks with washers and nuts (I used #8 diameter, but size is up to you.) In another life, I could have been a telephone engineer. Thanks for your answer,I will probably go with the 9:1 then. End fed 9:1 58ft wire and 17ft counterpose wire touching ground. /Creator (XnView) 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. For typical tuners built into a rig, /Producer (XnView, http://www.xnview.com) /Type /Pages SWR will vary based on topography, wire orientation and use of ground or counterpoise. tuner the colored bands below are the best lengths as long as your RFI Tips and Tricks /ModDate (D:20221212112042) 9 0 obj endobj Code Practice //-->, The "Best" Random Wire Antenna Lengths I made just a touch over 100 QSOs today with the new unit. 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. All you need for a random wire antenna is some wire, your tuner, one or more supports up as high as you can get them to string the wire from the supports to the tuner, at least one or two insulatorsand a little time. N4UJW. SSTV Start winding the Matching Auto Transformer, each pass through the center of the core equals one turn. presents an extremely high impedance to the tu config file by typing gnuplot rw.gnu. >> EFHW unun Resonant Long Wire 49:1 Transformer With BNC or SO-239 | Mobile Phones & Communication, Radio Communication Equipment, Antennas | eBay! 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 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. My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . SEARCH 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). 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. 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.