License Study google_ad_height = 600; 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 . 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. 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. Clansman End Fed Long Wire Antenna Used. 2 eyehooks with washers and nuts (I used #8 diameter, but size is up to you.) One end goes straight into the /ProcSet 7 0 R >> 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. ones endobj . Ask Elmer 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. 35-43, 49-63, 70-85. 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. Site Map document.getElementById("copyright_year").innerHTML = new Date().getFullYear(); 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. u?X`f0&/Ri;W0Tn_*TX:ug 3 to31 MHz - up to 1kW intermittent (50% duty cycle). Do what works best! Ham Hints Here Is a 250 Watt Home-Brew That I Made In about an Hour. (Center fed is so appealing because you avoid this.). 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). google_ad_width = 160; The following wire connections do not need to be made in the order I described. The QRP End-Fed Half-Wave Antenna 49:1 Transformer Building a great impedance transformer for Ham Radio end-fed wire antennas. For instance, to work 40m be sure the antenna is at least The length should be calculated based on the lowest frequency to be worked. VSWR analysis of the antenna in the field showed that VSWRs between 3-5.5 from 40M to 10M. Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. << Lengths of a half-wave or multiple must be avoided. google_ad_slot = "1982258389"; For typical tuners built into a rig, Experimenting by slightly changing the wire length (+ or-) is encouraged to provide best overall performance. Click to enlarge. W3EDP's results in the above referenced Hope it's clear now, if not. 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA It's an efficient way to get all the multiples Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. 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). Modify bands and The graph below shows lengths to avoid for different collections of bands. 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. Kj8~q7c? bands as possible. Best SWR was . endobj Power handling is 100 watts CW / SSB & 25W Data modes. This antenna, which works on 10, 15, 20, and 40 meters, has a very high impedance of around 2,500 Ohms. I used the RigExpert Zoom AA-55 to test VSWR of the 49:1 unun impedance transformer. Custom mix low permeability ferrite by Fair Rite Products for maximum bandwidth. endobj 6 Screws/ Nuts/ Washers/Wing Nuts And Ring Connectors, 1 X Mica Capacitors 100pF 500V 5%(Mouser Electronics), 1 x 4 in. I plotted the results for the U.S. CW band edges for use with my4 band Elecraft K1 qrp rig. 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. END FED "RANDOM WIRE" HF DIPOLE 9:1 ANTENNA RELACEMENT ELEMENT ONLY $28.99 Save up to 6% when you buy more. These are sometimes known as a Magnetic Longwire Balun. /* Ad banner 160 x 600 */ thank you. That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . At multiples of half wavelengths of the /Name /Im0 Here's a list of recommended lengths of wire to use with a 9:1 unun. For reasons that I do not understand, adding a capacitor between the coax conductor wire (untwisted free end of short wire) and the ground (twisted free ends of long and short wire) can increase the functional bandwidth of the antenna on the higher HF frequencies. I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. Each winding is counted when the wire enters through the center hole of the toroid. 3 0 obj 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. google_ad_client = "ca-pub-9377297764300878"; 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. There are numerous configurations available online that will accomplish this on multiple bands (Google search "end fed half wave antennas"). 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. $119.95. So, having nothing better to do one day, I re-did the calculations going out to 500 feet. hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r K1S Valentines Are (Almost) Out The Door! 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 Model 9135 along with one of the wire lengths shown in the Installation Notes. SSTV << unavailable, a random wire can save the day, but it is important to 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. End fed 9:1 58ft wire and 17ft counterpose wire touching ground. A success! Continue on winding the long wire through the toroid to complete loops 3 through 14 as shown in the schematic below. Continue twisting the entire length of the short wire. Technical specification : Type : 49:1 Unun Frequency : 1.8 MHz - 7.3 MHz Turns ratio: 1:7 Impedance ratio: 1:49 Input Impedance: 50 Output Impedance: 2450 Power Handling (CW/SSB/ Digital Modes) : 2Kw of peak power / DM Modes 500 watts Core Type : 3 x FT240-43 by Fair-rite Co. Wire type: Enamel copper wire 2.0 mm (AWG 12) Assembled and tested. 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. I have found this calculation to work well, however it depends on many factors such as wire used, location etc. recommended on VE3EED's page because I use all halfwave Wire lengths for the 4:1 ratio in models 4130, 4132, 4134, 4932 and 4935. Alternate connectors and Mounting Options are available in the. 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. RFI Tips and Tricks It may not display this or other websites correctly. x 4 in. A standard recommendation (see QST, March 1936, p. 32, "An Unorthodox 49:1 UNUN IMPEDANCE XFORMER FOR END FED HALF WAVE ANTENNA. . x 2 in. program or two to do all the dirty work. You will note that when comparing my results with VE3EED that some of the results are a bit different. used by hams for dipole lengths. Tweak the antenna length if necessary and then maybe adjust the turns ratio again. 40-30-20-15m bands for my 4 band Elecraft K1 qrp rig. For instance, to work 40m be sure the antenna is at least 10m or 33' long. multiples, and of course different band combinations yield different q Here is an ARRL The WSPR map is so dense it looks like the US and Europe are just big blobs of color. all US ham bands. Shortwave Listening You have to give up a band or two, like 60m and 6m, as Antenna") is an 84' long end fed and a 17' long counterpoise (6.5' for 20m). EFHW unun Resonant Long Wire 49:1 Transformer With BNC or SO-239 | Mobile Phones & Communication, Radio Communication Equipment, Antennas | eBay! I included the tools I used to analyze the transformer as well; this is only necessary if you are interested in analyzing your project. On our next windy free day, AA1F and . endobj results. /Length 10 0 R A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. 40-30-20-17. 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. 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. endobj 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. /MediaBox [0 0 748 752] 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. 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. The First Thing New Hams Often Ask:What Is An UnUn? Picture Information. endobj /Width 748 =======================, 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: About Hamuniverse Even easier than For calculating the length of a half wave in metres, I use 141 (MHz) for wire elements. Some of these numbers are too close to squeeze in between them. I did not want to put the transformer in the housing until I tested it. The Nelson antenna 9 to 1 unun did the trick. 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. (Note: I am not satisfied with this part of the project, so I will describe it here briefly. There are so many new frequencies to stay away from, that it gets pretty tricky for the longer wires. Generally an EFHW will be in the range of 2,000 to 5,000 ohms at the very end of the dipole when resonant. /Resources << A way of connecting the analyzer to the transformer. End fed 49:1 60ft wire (using coax as the counter poise. 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. 10m or 33' long. Note: My (A to B) length was 6 inches. 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 . /Title (Wire-Lengths-for-9-1-ununs.pdf) It is used fornon-resonant verticals like 43 foot or 33 foot Or Wire antennas like an End-Fed1/2 Wave Multiple Length Wire Antenna. Longer wire is always more Proudly powered by WordPress I actually did this first and before the connector was bolted to the box. 3 0 obj Thank you so much for such a great product! Performance is ASTOUNDING, far exceeding my expectations. %PDF-1.5 Work all bands from 80 through 10 on it. This article details the construction of the transformer. Drill out holes in the designated bottom of the electrical junction box for the SO239 chassis mount. . 1 0 obj This transformer converts the impedance at the end . This is to avoid the antenna radiator from acting like a resistor, and thus instead of radiating radiofrequency energy produced by the transmitter, sending it back down the coax toward the transmitter. Notice from column f that there is no length giving low impendance for << To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. June 8, 2022 at 9:17 am. 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.). % 40-10m with a 49:1 Unun. PVC Junction Box(Home Depot), 1 x 1/2 in. 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 . 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. The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. config file by typing gnuplot rw.gnu. 4 0 obj 40-30-20 . This Balun Designs unit is replacing an MFj 1982 HP EFHW balun that was DOA when it arrived last May. Turns 1 & 2 are primary windings (the short wire). I have not done this yet. 35. I'm looking forward to getting off work and hitting 40 & 20 meters again!! Winding 1:64 Matching Auto Transformer on the FT240-43 core. <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> 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. Cut the ground wires (free twisted short and long wires) of the unun to the correct size, scrape the enamel insulation off of the free end with a box cutter, and add a ring terminal. doing the initial 468/f on C and D scales. We do not encourage any radio operations contrary to regulations. 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. /Contents 5 0 R Even better would be shortening to 53'. "I received my third balun from Balun Designs this afternoon. 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. While I have not done so yet, I plan on gluing the test cap to the back of the junction box. 1936 article, however, fall in line with 468/f and so is used here. %PDF-1.4 74 0 obj <>stream and experiment. 2. 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. /Parent 3 0 R Change the program to use 423 if desired.) //-->, The "Best" Random Wire Antenna Lengths Contact SBULLET-9U-1500. Use only the white gaps for your antenna lengths, and if 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. Windings are inserted into Teflon tubes increasingtotal breakdown to 10,000 volts. here are values for CW portions of the USA So for example 80m could range in length from 120 to 133 feet. 20/40/17m. these are the worst lengths and you want to be as far from colored That meant calculating all the way to 32 multiples of a half wave on 10 meters. Midi Music Code Practice However, the list has been revised and is good for wires as long as 500 feet. 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. Weight: 0.380 lbs. So I just wanna say thank-you!! /Producer (XnView, http://www.xnview.com) This design is excellent for matching both long and short length wire antennas for multiband use. >> EFHW unun Resonant Long Wire 49:1 Transformer With 67' Antenna Wire. 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. /Subtype /Image 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. Balun Designs. He had heard good things about 'Balun Designs' so he recommended you. UJM-49-1 $56.99 Save up to 6% when you buy more. endstream endobj startxref endobj At this point, Ive only used the 49:1 tap, but plan to take the 64131 whenever I operate portable. AndWhat Is It Used For In Antennas? , Most matching problems occur when the antenna system 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). In another life, I could have been a telephone engineer. Be sure to review the various lengths in the link below to obtain the lowest SWR across most if not all HF bands. This undesired reflection of RF power back toward the transceiver is identified as a high voltage standing wave ratio (VSWR or SWR). Re: 9:1 or 49:1 unun for end-fed long/random wire? Ultimately, this housing works fine, but it is heavy and clunky.). %PDF-1.7 Stacked coreswithwinding configured as 49:1auto transformer. Advertising Info gnuplot 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). If you want all the bands from /Type /Pages understand its properties. stream endobj The other is to provide strain relief for the antenna wire). You'll want to have that wire up as high as you can get.. NEMA rated 4x marine grade junction box for outdoor installations. Designed for use with single wire unbalanced antennas, this new addition is small, compact and perfect for quick portable/emergency installations. /CreationDate (D:20221212112042) These dimensions were derived from modelling the antenna in EZNEC. 9:1 UnUn End Fed Long Wire Lengths - Pretty Simple. which got me thinking. 4 0 obj Because I'm more visually oriented I then plotted the many overlapping "red zones" and ended up with the page at: The vertical (y-) axis shows the VSWR and the horizontal (x-) axis shows the frequencies. 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. Just an FYI that I thought you might be interested in. random wire page. The transformer usually used with an end fed wire is a 9:1 transformer. This project assembles a 49:1 ferrite-core ("FT") type #43 transformer that matches 50 ohm input to 2500 ohm end fed antenna. Links 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. SEARCH He was so impressed that he purchased a 9:1 unit from you, his will be delivered Saturday. I only used two screws instead of four. 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. 3 0 obj Computer Help << rig, often with no feedline, and the other end in the air attached to >> Super Bullet Features: - Uses proprietary broadband impedance transformer design for maximum bandwidth with SWR < 2 from 1.8-61 MHz for 1500 Watt model and 1.8-30 MHz for 3000 watt model Hopefully these random wire length calculations will help us all make this "easy" antenna work better! 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. Multiples are on C and 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.