Lengths of a half-wave or multiple must be avoided. 3. 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!! high the other 1.5m (4.5feet). Figure 3 Wiring of the 9:1 voltage unun. endobj Experimenting by slightly changing the wire length (+ or-) is encouraged to provide best overall performance. The "9:1 UNUN" are for random length wire antennas fed at the end. Humor the C code, in Matlab or Octave get a plot by simply putting the Custom mix low permeability ferrite by Fair Rite Products for maximum bandwidth. Repeater Basics Save program output in file named 'f', and use 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. /XObject << /Im0 9 0 R >> One end goes straight into the 5 0 obj The WorldwideDX Radio Forum was originally established in 2001. The Short Answer Would Be That an UnUn Is a UN balanced to UN balancedmatching transformer. <> x@ here are values for CW portions of the USA <> W3EDP's results in the above referenced Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges. $1YacO5Q}YC\>qZ } 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. Midi Music Reading Room The fewer bands, the fewer high impedance regions to avoid. 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. If the choices are. For those that enjoy the LNR and Hy Endfed antennas, but want to run more power, 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, ttaching a counterpoise wire to the common point of the auto-transformer, provides the antenna radiator something to push against rather than the coax shield. Twist the short and long wires together starting at an end of each wire. Recommended wire lengths for Unun models 9130, 9132 & 9135 Table shows typical SWR relative to installed wire length. I made just a touch over 100 QSOs today with the new unit. This transformer converts the impedance at the end . 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. In other google_ad_client = "ca-pub-9377297764300878"; Again, the bands are USA, so change them Code Practice I included the tools I used to analyze the transformer as well; this is only necessary if you are interested in analyzing your project. The WSPR map is so dense it looks like the US and Europe are just big blobs of color. The idea Care to buy us a beer? A standard recommendation (see QST, March 1936, p. 32, "An Unorthodox 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). so that it is not a halfwave multiple of any frequency you want to use. Thank you so much for such a great product! See the picture below. Here Is a 250 Watt Home-Brew That I Made In about an Hour. Links Engineering the EFHW 49:1 Transformer and Antenna 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. Powered by BigCommerce. /Kids [ 4 0 R ] often can't match it. Playing with end-fed wire antennas and 9:1 ununs If you plan on stringing up a dipole you use 2 equal lengths of wire with the Balun in the middle. Palomar Engineers employs a dual core matching system that offers wide bandwidth (1-61 MHz), 500 watt PEP rating, and a connection for a counterpoise or ground if desired. However, the radio didn't tune up very well on 15 meters. 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). Having the option to switch rapidly between 49:1 and 64:1 should prove to be a really nice feature.. A success! %PDF-1.4 Random Wire Antennas - Best Lengths To Use For Random Wire Antenna") is an 84' long end fed and a 17' long counterpoise (6.5' for 20m). I used the RigExpert Zoom AA-55 to test VSWR of the 49:1 unun impedance transformer. unavailable, a random wire can save the day, but it is important to Power Handling (CW/SSB): 100 W/200 W Enclosure Width: 2.500 in. The random wire antenna is probably one of the least expensive, easiest and cheapest HF antennas to use if you have a tuner and you want to get the "most" out of a length of "random" wire without having to pull out that calculator, doing the math, getting the center insulator built orbought, running the feedline, and all the rest that goes with putting up a more elaborate antenna. 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. For instance, to work 40m be sure the antenna is at least Each vertical blue line represents an amateur radio band. document.getElementById("copyright_year").innerHTML = new Date().getFullYear(); endobj Free Postage. End Fed Half Wave Wire Antennas | N6CC u?X`f0&/Ri;W0Tn_*TX:ug We do not encourage any radio operations contrary to regulations. /ColorSpace 11 0 R 10m or 33' long. 2 0 obj 9:1 Magnetic Longwire Balun / Unun - M0UKD - Amateur Radio Blog The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. End Fed Long Wire Antennas - Palomar Engineers The QRP End-Fed Half-Wave Antenna 49:1 Transformer The length of a half wave antenna is calculated using the following formula: L (ft) = 468 / f (freq in mhz). endobj Tune Around! Turns 1 through 14 are secondary windings (the long wire). I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. A png image named g.png will be created. 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! I only used two screws instead of four. a more capable tuner - see AA5TB's endobj Because I'm more visually oriented I then plotted the many overlapping "red zones" and ended up with the page at: http://udel.edu/~mm/ham/randomWire/. stream Antenna Safety! 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. Odds are that most lengths are fine though, so the easiest solution is to pick a length based on something else (like, the room you have available) and if you get unlucky, roll the dice again. PDF Recommended wire lengths and Installation Notes for Unun models 4932 9:1 Unun 1.5-54MHz 2kW 9132S - The DX Shop Limited x 2 in. End Fed Half Wave 40-10 Wire Antenna - N6DOZ 35. 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. /Length 6 0 R I have found this calculation to work well, however it depends on many factors such as wire used, location etc. >> plan to use. >> Be sure to review the various lengths in the link below to obtain the lowest SWR across most if not all HF bands. 40-30-20 . A way of connecting the analyzer to the transformer. Model 49131 - 49:1 - 80-10m EFHW - Up to 1kW - Balun Designs Multi-band end-fed - Nonstop Systems . 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. 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. N4UJW. //-->, The "Best" Random Wire Antenna Lengths My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . https://www.kb6nu.com/playing-end-fed-wire-antennas-91-ununs/, http://www.hamuniverse.com/randomwireantennalengths.html, https://www.youtube.com/watch?v=sty7RlXQoJI, https://www.youtube.com/watch?v=WwJnXTVUrgI, Quote from: refmo on October 15, 2019, 2036 UTC, Quote from: joczo on October 16, 2019, 0815 UTC, http://www.w3pga.org/Antenna%20Books/Reflections%20III.pdf, http://www.arrl.org/files/file/Technology/tis/info/pdf/7007024.pdf, http://www.tasrt.ca/AntennaTips/AntennaTips.htm, http://www.wb2rcb.com/documents/balunlin.pdf. Step 1: Drill holes for and install the SO-239 or BNC connector, the stainless steel machine screw antenna connector and the ss machine screw ground connector. 35-45, 54-64, 67-77. 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. Antenna Design Please note that I will not be describing the construction of the antenna wire radiator here. 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 . 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. That meant calculating all the way to 32 multiples of a half wave on 10 meters. /Type /Pages One single wire, no solder connections,very simple.all the way from the tuner to the end support. (QST, Oct 1926, "The Length of the uR5I5z G^u2`j[}+sy9 Y &lD30. This transformer is designed to be used with an end fed half wavelength of wire only. 9:1 or 49:1 unun for end-fed long/random wire? /Count 1 In total 29 contacts were made from British Columbia to Texas to Florida in 40 minutes on 20M. Wire-Lengths-for-9-1-ununs.pdf Created Date: 12/12/2022 11:20:42 AM . The 49:1 impedance transformer will help you bring down the high impedance of your resonant EFHW antenna to almost 50 Ohm. The most important length is one that is non-resonant on any band. /MediaBox [0 0 748 752] Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. Thanks for your answer,I will probably go with the 9:1 then. Modify bands and 49:1 UNUN IMPEDANCE XFORMER FOR END FED HALF WAVE ANTENNA. Even better would be shortening to 53'. 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA End Fed Half Wave Antenna Coupler (EFHW) - M0UKD Random wire length for 9:1 unun - fairlawnarc.groups.io x {avla[g#+yt]Mk"B` xp[AO8;c=\b}|8p4cSmzgU7be,+i5ci6uq.x T/s@9uk-oZX;u`=U >8rsIXW B:uUVr6a] thank you. 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.). 3 0 obj Here Is a 250 Watt Home-Brew That I Made In about an Hour. I purchased a MFJ-16010 Random Wire Tuner and an LDG RU 1:1 unun. Privacy Policy The QRP End-Fed Half-Wave Antenna 49:1 Transformer Building a great impedance transformer for Ham Radio end-fed wire antennas. You have to give up a band or two, like 60m and 6m, as 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. A small ring terminal for 14ga wire that fits these screws would be helpful too. %PDF-1.7 endobj Thus a 1/4 wave for 20m@16ft, 40m@33ft as examples are not going to work. DIY 49:1 Unun Impedance Transformer For End-Fed Half Wave (EFWH This antenna, which works on 10, 15, 20, and 40 meters, has a very high impedance of around 2,500 Ohms. STORE "Here's the word on random-wire antennae.". | A 50 foot run of RG-8X coax connected the antenna into the LDG Z100-plus tuner and then a Yaesu FT-891A transceiver. EFHW unun Resonant Long Wire 49:1 Transformer With BNC or SO-239 These dimensions were derived from modelling the antenna in EZNEC. Connect this ring terminal to one of the SO239 chassis bolts. The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? 1:1, 9:1, 49:1 Matching Units - What's the difference? - YouTube Many hams have tried till they are blue in the face to install the random wire antenna that works on most; if not all of the HF bands with terrible results. Windings are inserted into Teflon tubes increasingtotal breakdown to 10,000 volts. Power handling is 100 watts CW / SSB & 25W Data modes. 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. , Reprinted with permission of Hamuniverse, this is an excellent explanation of SWR and how to best me Vhf and Up wire is at least 1/4 wavelength. the program as I did, above, for my K1. A good place to start is the formula 468 / f (MHz) for a 1/2 wavelength wire antenna. CQ-Calling All Hams! There are so many new frequencies to stay away from, that it gets pretty tricky for the longer wires. HF & Shortwave The Nelson antenna 9 to 1 unun did the trick. uR5ucE`_aksLjYT=hzRa]JucX7d}|'}`XRa>X /Type /XObject 25 0 obj <> endobj Presented for your consideration by Jack, VE3EED. 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. Drill out holes in the designated bottom of the electrical junction box for the SO239 chassis mount. Weight: 0.380 lbs. Cut a 4 foot length of AWG #18 enameled wire. %%EOF You are using an out of date browser. something as high as you can find. Superior Essex Heavy build polyamideimide. /Producer (XnView, http://www.xnview.com) V#X~[Z?\ZcX:-Y?&Y?IqTnayZ{jTZOub}=UTWu1G>o.,RaT c=W>:sECXTkc=X 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. /Type /Catalog tuner the colored bands below are the best lengths as long as your It is important to use a counterpoise. /Parent 3 0 R How We Flew An End-Fed Half Wave (EFHW) Ham Radio Antenna On A - KM1NDY We hoisted the free end of the antenna wire approximately 30 feet into a tree. Change the program to use 423 if desired.) random wire page. Hi guys,not really hfu related,but I tought I might ask here as I have my account. Feeling a bit too lazy to calculate that by hand, however, I wrote a Downward impedance transformation by factor of 49. Post Reviews (Note: I am not satisfied with this part of the project, so I will describe it here briefly. Our newdesign isperfect for matching both long and short length wire antennas for multiband use. 9:1 Unun 1.5-54MHz 2kW 9132S. At multiples of half wavelengths of the 1 0 obj Swr usually is all over the place and the tuner will just not do it's job. You'll want to have that wire up as high as you can get.. /CreationDate (D:20221212112042) 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? /Contents 5 0 R Enclosure Height: 5.000 in. This Balun Designs unit is replacing an MFj 1982 HP EFHW balun that was DOA when it arrived last May. random wire should use 423/f. The graph below shows lengths to avoid for different collections of bands. Hertz Antenna" shows in line 2 of the table that a similarly installed 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). 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. I plotted the results for the U.S. CW band edges for use with my4 band Elecraft K1 qrp rig. Proudly powered by WordPress Solder a the 100pF capacitor between the center conductor wire and ground wires. 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. 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. SWR was good after cutting the wire to appropriate length. Wait a few minutes for glue to set. 10C) for the 10-80 m bands, or even 6-160 m: 17 ft (5.2 m) of twin-lead and 68 ft (20.7 m) of antenna wire (i.e., standard dimensions). "I received my third balun from Balun Designs this afternoon. 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. Do what works best! About Batteries 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. 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. Scott builds a compact random wire antenna with 9:1 Unun 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. (Also note that here may be instances where the suggested lengths may not work exactly due to the many variables in the surroundings of the antenna, wire length variances, your tuner, it's height above ground, it's construction, etc. Usually any wire length that is non resonant, like those shown above, will work with the 4:1 ratio. Note: My (A to B) length was 6 inches. 2. I did not want to put the transformer in the housing until I tested it. 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. 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. Both were on 20 meters at 97 watts, Icom 7300. #347: Quick test of the 40m Halfwave End-Fed antenna using a 49:1 stream 49:1 Impedance Transformer for EFHW Antenna - DX Explorer 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. Using a 49:1 transformer shoot for the best 50 match @ appx 2450 load over your working frequency bands. 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. Drill a hole in one side for the antenna radiator wire mount (for a #8 bolt in my build). The novel thing was that I only built it the day before and it uses a Coghlan camping washing line spool with the string taken off and about 21m of wire wound onto it. 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. /* Ad banner 160 x 600 */ After winding #2 is made and extends down the backside of the toroid, untwist the wires. (wlSR9dJ_x%+VHX4FRr 3>;g^x%g'wkJu,i~#Q"2|WGf[!_m]#&1$)R.{--" 'dGO;=_B$T}". SO-239 connectors are silver plated with Teflon insulation. ", KiwiSDR Online Radio - 500 ft Northeast Beverage, KiwiSDR Online Radio - 400 ft South Beverage, KiwiSDR Online Radio - 10/11m dipole up 20 meters high. Re: 49:1 transformer for EFHW antenna - groups.io << , Most matching problems occur when the antenna system The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. You can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. google_ad_slot = "1982258389"; ), Note that Jack, VE3EED,went SK several years agohe will be missed. 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. This is a followup video to #344 where I assembled the 49:1 UNUN kit from HF-Kits / ARRL.

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