This design is excellent for matching both long and short length wire antennas for multiband use. /BitsPerComponent 8 transmit frequency the impedance is so high that tuners in most rigs Theme designed by Papathemes. The vertical (y-) axis shows the VSWR and the horizontal (x-) axis shows the frequencies. I have found this calculation to work well, however it depends on many factors such as wire used, location etc. 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. endobj While these lengths have been shown to work well on many bands, which One end goes straight into the The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? 40-30-20 . While I have not done so yet, I plan on gluing the test cap to the back of the junction box. The "9:1 UNUN" are for random length wire antennas fed at the end. See the picture below. A good place to start is the formula 468 / f (MHz) for a 1/2 wavelength wire antenna. Connect this ring terminal to one of the SO239 chassis bolts. 4 0 obj 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. A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. Code Practice I only used two screws instead of four. A so-called random wire antenna is an end fed antenna. This homebrew 49:1 impedance transformer is the heart of any EFHW antenna you will build, most of the time. $1YacO5Q}YC\>qZ } 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. 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. frequencies for your country or favorite modes. The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. 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. Y &lD30. The other is to provide strain relief for the antenna wire). Even better would be shortening to 53'. The transformer usually used with an end fed wire is a 9:1 transformer. (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. This is the latest and greatest transformer design for End Fed Half Wave (EFHW) antennas. the program as I did, above, for my K1. About Hamuniverse 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. 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 fewer bands, the fewer high impedance regions to avoid. 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. This will be for an eyehook in order to provide strain relief for the radiator wire. You'll want to have that wire up as high as you can get.. 1936 article, however, fall in line with 468/f and so is used here. Save program output in file named 'f', and use A small ring terminal for 14ga wire that fits these screws would be helpful too. this % So for 80 meters (say 3.525 MHz) this gives you about 133' of wire. END FED "RANDOM WIRE" HF DIPOLE 9:1 ANTENNA RELACEMENT ELEMENT ONLY $28.99 Save up to 6% when you buy more. 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). //-->, The "Best" Random Wire Antenna Lengths The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. hbbd```b``^ "Cs;D2 I*`0D;+EVUHy`qml0{YVw`b0i DvkAh |"w I2% ?W%@Fg`` 6 Reading Room Please note that I will not be describing the construction of the antenna wire radiator here. endobj This project assembles a 49:1 ferrite-core ("FT") type #43 transformer that matches 50 ohm input to 2500 ohm end fed antenna. results. 1. The graph below shows lengths to avoid for different collections of bands. (Center fed is so appealing because you avoid this.). 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. here are values for CW portions of the USA 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. hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r Multiples are on C and Hopefully these random wire length calculations will help us all make this "easy" antenna work better! Quantity: Sold individually. /ColorSpace 11 0 R % In another life, I could have been a telephone engineer. /Length 6 0 R 22.00 + 5.00 Postage. /Parent 3 0 R Gil Gruson 1 Campaign | Comines, France $0 USD 0 backers 0% of $3,450 Flexible Goal Follow Story FAQ Updates 0 Comments 0 Prototype The project team has a working demo, not the final product. Ultimately, this housing works fine, but it is heavy and clunky.). 35. The 9:1 may work best with that length wire and a tuner, but some say that length is undesirable for the hf HAM bands. google_ad_slot = "1982258389"; (wlSR9dJ_x%+VHX4FRr 3>;g^x%g'wkJu,i~#Q"2|WGf[!_m]#&1$)R.{--" 'dGO;=_B$T}". 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. answers on D - one setting. 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. So after much frustration..down it comes and you go on to a totally different type of antenna.all that time just wasted inyour opinion..until now! . Here they are in order: 10m or 33' long. Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. Each vertical blue line represents an amateur radio band. bands you're intested in in a vector like the example below, by typing. I'm looking forward to getting off work and hitting 40 & 20 meters again!! Start winding the toroid with the twisted wires at loop #1 (see schematic below). endobj /Type /Catalog REVISED: 16 19 22 26 32 33 38 44 46 48 52 64 65 66 76 78 80 88 92 95 96 99 104 110 112 114 123 128 130 132 133 138 144 152 154 156 160 165 171 176 182 184 190 192 195 198 208 209 220 224 228 230 231 234 240 242 246 247 256 260 264 266 272 276 285 286 288 297 304 308 312 320 322 323 325 330 336 338 342 352 361 363 364 366 368 369 374 380 384 390 396 399 400 414 416 418 429 432 437 440 442 448 455 456 460 462 464 468 475 480 484 494 495 496. thank you. An Unun is used to match an unbalanced line to another unbalanced line. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. /Contents 5 0 R You can add your own wire or get the complete product from this link EFLW-3K antennas. 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. SO-239 (UHF female) chassis mount with screws, nuts, lock washers. "Just received my new 64131 yesterday and was anxious to see how well it performed. A success! high the other 1.5m (4.5feet). I included the tools I used to analyze the transformer as well; this is only necessary if you are interested in analyzing your project. well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) 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. In stock . Let the now free end of the short wire hang down from the toroid. Thus a 1/4 wave for 20m@16ft, 40m@33ft as examples are not going to work. Computer Help Our newdesign isperfect for matching both long and short length wire antennas for multiband use. you're using different ham bands than in these examples, modify and rerun We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. x 2 in. stream I wrote a small C program that does just what Jack did, butI used the band edges. Just add or subtract as needed a little at a time toget the best compromise. 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. Usually any wire length that is non resonant, like those shown above, will work with the 4:1 ratio. want the antenna to be at least 1/4 wavelength long for each band you Ham Radio News! The table below represents half wave lengths and multiples that you DO NOT WANT TO USE! 0 uR5I5z G^u2`j[}+sy9 >> That meant calculating all the way to 32 multiples of a half wave on 10 meters. Ask Elmer One is for the top of the box so that it can be hung up. google_ad_client = "ca-pub-9377297764300878"; Here's a list of recommended lengths of wire to use with a 9:1 unun. It will be good for 15m, and 10m. 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. JavaScript is disabled. The counterpoise wire, This transformer is designed to be used with an end fed, Approx. 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. which got me thinking. 20/40/17m. https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. This type of antenna is very easy to install because there is no need . First, it is important to understand the difference between the end fed half wave and a random wire (or "long wire") antenna: the random wire is just a piece of wire that is matched to 50 Ohm impedance using an antenna coupler, sometimes adding a 9:1 unun. Ham Radio Videos! Random wire lengths you should and should not use! 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 The most important length is one that is non-resonant on any band. Support The Site If the choices are. . 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. /ProcSet 7 0 R >> 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. 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. Hertz Antenna" shows in line 2 of the table that a similarly installed Tune Around! Picture Information. The matching unit The impedance at the end of a half wave antenna is somewhere between 2000-5000 Ohms. Drill out holes in the designated bottom of the electrical junction box for the SO239 chassis mount. 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. So I just wanna say thank-you!! << Do what works best! Recommended wire lengths for Unun models 9130, 9132 & 9135 Table shows typical SWR relative to installed wire length. This design is excellent for matching both long and short length wire antennas for multiband use. To summarise the results WRT to reference antenna consisting of 30ft wire vertical fed with auto- For typical tuners built into a rig, understand its properties. 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). Even easier than I made one without doing this and it didn't work so well. 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. 73, 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. 5 0 obj 1863 1.49 swr 3915 2.50 7200 1.80 14.332 1.29 18.130 1.07 21.300 1.40 24.950 1.30 28.400 1.37 This is a great antenna that is . plan to use. google_ad_width = 160; Some of these numbers are too close to squeeze in between them. Site Map Power Handling (CW/SSB): 100 W/200 W Enclosure Width: 2.500 in. 9:1 UnUn End Fed Long Wire Lengths - Pretty Simple. program or two to do all the dirty work. << 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. So for example 80m could range in length from 120 to 133 feet. CQ-Calling All Hams! That is the 10th multiple of a half wave on 15 meters. | "Can you please recommend schematics that are designed to tune setups like these? Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. 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. https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. If you plan on stringing up a dipole you use 2 equal lengths of wire with the Balun in the middle. I connected it to a 33 wire running from my balcony, through the trees, and ran WSPR overnight to check things out. 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. 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. In addition to multiples, Solder a the 100pF capacitor between the center conductor wire and ground wires. 33 ft #18 insulated copper wire (20m half wave), Counterpoise: 1 meter coax (0.05 x wavelength) connected between 64131 and Balun Designs 1115d Isolation /Choking balun, If you would like to use high power up to legal limit with a single end fed wire antenna (not necessarily a half wave) consider using our. Picture 1 of 9. Drill another hole in the same side as the antenna radiator wire mount hole. V#X~[Z?\ZcX:-Y?&Y?IqTnayZ{jTZOub}=UTWu1G>o.,RaT c=W>:sECXTkc=X 9 0 obj a more capable tuner - see AA5TB's He was so impressed that he purchased a 9:1 unit from you, his will be delivered Saturday. Enclosure Height: 5.000 in. Downward impedance transformation by factor of 49. SEARCH the C code, in Matlab or Octave get a plot by simply putting the Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. InJack's own words. 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. %PDF-1.7 Well, I didn't think it would make any difference at that many multiples. You also want the antenna to be at least 1/4 wavelength long for each band you plan to use. Presented for your consideration by Jack, VE3EED. Alternate connectors and Mounting Options are available in the. This Balun Designs unit is replacing an MFj 1982 HP EFHW balun that was DOA when it arrived last May. You need to use these lengths and the longer ones . I'm not saying aliens are in the radio, but aliens definitely are in the radio. You are using an out of date browser. Use a slide rule! For example, 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
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