endobj >> Best SWR was . random wire should use 423/f. Humor For typical tuners built into a rig, | 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. Do what works best! Start winding the toroid with the twisted wires at loop #1 (see schematic below). We are working every day to make sure our community is the best Radio Hobbyist's site. 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. /Title (Wire-Lengths-for-9-1-ununs.pdf) Cannon". Let's have a look at a few details on how to build a 49:1 impedance . Use with other lengths can potentially damage the transformer depending on power level in use. SO-239 connectors are silver plated with Teflon insulation. We hoisted the free end of the antenna wire approximately 30 feet into a tree. . % 1936 article, however, fall in line with 468/f and so is used here. 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. endobj I did not want to put the transformer in the housing until I tested it. 4 0 obj Again, the bands are USA, so change them So, having nothing better to do one day, I re-did the calculations going out to 500 feet. /Type /Pages A Balun is used to match a balanced line to an unbalanced line. hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r This antenna, which works on 10, 15, 20, and 40 meters, has a very high impedance of around 2,500 Ohms. 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. Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. 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. Ask Elmer ?7{*. /Type /Catalog Note: My (A to B) length was 6 inches. 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. 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. Multiples are on C and endobj &nb 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. answers on D - one setting. The unun was floating at about 15 feet above ground. shown in the column e. var sc_project=8077274; Midi Music 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. You will note that when comparing my results with VE3EED that some of the results are a bit different. . So you have the freq range of interest and the total length of the wire, figuring out wich balun will be a better match for 50ohm coax should be easy. /&KWA7{L=D]g0Z!F9;V{zL[h-D,u(.9rg(RHI{f t*C/?? Q and leave the unun on the ground. frequencies for your country or favorite modes. 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. 9:1 or 49:1 unun for end-fed long/random wire? Use a slide rule! /Producer (XnView, http://www.xnview.com) endstream endobj startxref /Name /Im0 I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. 1 0 obj A few more comments about this 49:1 autotransformer EFHW design. 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. 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. Ham Radio Videos! 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. 10m or 33' long. 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. The popular End-Fed Half-Wave (EFHW) Antenna is an easily portable, high-impedance (2,000-4,000 ohm) wire antenna that resonates on its fundamental frequency and all harmonics above. 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. However, the radio didn't tune up very well on 15 meters. 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!! NOTE: Rewording the previous paragraph, if you have a capable enough 3 to31 MHz - up to 1kW intermittent (50% duty cycle). 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 Feeling a bit too lazy to calculate that by hand, however, I wrote a The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. You need to use these lengths and the longer ones . << ), Note that Jack, VE3EED,went SK several years agohe will be missed. Re: 9:1 or 49:1 unun for end-fed long/random wire? Anyway, an old friend mentioned 'MyAntenna.com' but they were closed for the summer. Support The Site I have found this calculation to work well, however it depends on many factors such as wire used, location etc. 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. . Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges. A small ring terminal for 14ga wire that fits these screws would be helpful too. The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. I attached the toroids to a PVC DWV test cap with 3 cable ties. 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. I made one without doing this and it didn't work so well. gnuplot This transformer is designed to be used with an end fed half wavelength of wire only. Weight: 0.380 lbs. I use this 8010 EFHW at home, too. %PDF-1.7 On our next windy free day, AA1F and . Jack, VE3EED - SK. x 2 in. Twist the short and long wires together starting at an end of each wire. This is considered a random wire end fed antenna, not to be confused with a half wave end fed antenna which uses a 49:1 or 64:1 unun and a wire that is a half wave length. About Hamuniverse An Unun is used to match an unbalanced line to another unbalanced line. /Filter [ /FlateDecode ] An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). Here I show finalizing the antenna, getting it in the air, and run. About Batteries 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. 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. //-->, The "Best" Random Wire Antenna Lengths Click to enlarge. <>>> something as high as you can find. The length should be calculated based on the lowest frequency to be worked. A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. 49:1 End Fed Half Wave Antenna 40-10M 100W Version Bands of operation 40,20,15 & 10m using 67 feet of our UV, Ozone resistant Antenna wire. (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. This article explains why the use of mix 43 for HF applications is almost always a mistake. 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.). 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). SBULLET-9U-1500. He had heard good things about 'Balun Designs' so he recommended you. The following wire connections do not need to be made in the order I described. 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. . 1. 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. <>/Metadata 239 0 R/ViewerPreferences 240 0 R>> See the picture below. I say run what you got and don't worry about it. /Width 748 35-45, 54-64, 67-77. Having the option to switch rapidly between 49:1 and 64:1 should prove to be a really nice feature.. endobj The First Thing New Hams Often Ask:What Is An UnUn? 2 eyehooks with washers and nuts (I used #8 diameter, but size is up to you.) Well, I didn't think it would make any difference at that many multiples. 35. 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 . So for example 80m could range in length from 120 to 133 feet. The matching unit The impedance at the end of a half wave antenna is somewhere between 2000-5000 Ohms. AndWhat Is It Used For In Antennas? 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. "I received my third balun from Balun Designs this afternoon. Tools hbbd```b``^ "Cs;D2 I*`0D;+EVUHy`qml0{YVw`b0i DvkAh |"w I2% ?W%@Fg`` 6 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. This is a followup video to #344 where I assembled the 49:1 UNUN kit from HF-Kits / ARRL. Advertising Info The Short Answer Would Be That an UnUn Is a "UN balanced to UN balanced" matching transformer. END FED "RANDOM WIRE" HF DIPOLE 9:1 ANTENNA RELACEMENT ELEMENT ONLY $28.99 Save up to 6% when you buy more. I'm looking forward to getting off work and hitting 40 & 20 meters again!! rig, often with no feedline, and the other end in the air attached to Power handling is 100 watts CW / SSB & 25W Data modes. A 50 foot run of RG-8X coax connected the antenna into the LDG Z100-plus tuner and then a Yaesu FT-891A transceiver. These dimensions were derived from modelling the antenna in EZNEC. "Here's the word on random-wire antennae.". endobj Turns 1 & 2 are primary windings (the short wire). UJM-49-1 $56.99 Save up to 6% when you buy more. Make sure the beginning few inches of twisted wire is not involved in the winding (i.e., just hanging down from the toroid). While these lengths have been shown to work well on many bands, which are blocked out because an antenna should be at least that long. Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. The idea When used with the stated Balun Designsis now offering a low power alternative for those who want to use an End Fed Half Wave for portable or temporary installations. 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. "Can you please recommend schematics that are designed to tune setups like these? stream My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . var sc_security="1df091cc". Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. endobj >> wire lengths less than 1/4 wavelength of the lowest desired frequency If the choices are. 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. recommended on VE3EED's page because I use all halfwave tuner the colored bands below are the best lengths as long as your Caution: When used atfull power rating of 1kW, the antenna must have a low SWRon the band selected and be used on a 50% duty cycle. 7 0 obj Code Practice Privacy Policy Some of these numbers are too close to squeeze in between them. << presents an extremely high impedance to the tu 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA We recently found some good information about random wire lengths that you should and should not use. this The 30 day return period lapsed before I could get the antenna deployed to test it. >> 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. Continue on winding the long wire through the toroid to complete loops 3 through 14 as shown in the schematic below. Lengths of a half-wave or multiple must be avoided. 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. Product Reviews 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. Windings are inserted into Teflon tubes increasingtotal breakdown to 10,000 volts. 40-10m with a 49:1 Unun. So those are the numbers above thatwe have to stay as far away from as possible when building a long-wire antenna. SSTV Connect this ring terminal to one of the SO239 chassis bolts. Theme: Newsup by Themeansar. Cut a 4 foot length of AWG #18 enameled wire. 20/40/17m. endobj For a better experience, please enable JavaScript in your browser before proceeding. the C code, in Matlab or Octave get a plot by simply putting the Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 1500 Watts, End Fed Antennas. It is important to use a counterpoise. Repeater Builders 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. Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. thank you. 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. 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. Hertz Antenna" shows in line 2 of the table that a similarly installed I connected it to a 33 wire running from my balcony, through the trees, and ran WSPR overnight to check things out. 31 The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. I will also find some sort of heat resistant packing material to help hold the transformer in place. excellent page for EFHW info - or, addressed below, to cut the wire Performance is ASTOUNDING, far exceeding my expectations. . 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 ones Here Is a 250 Watt Home-Brew That I Made In about an Hour. You'll want to have that wire up as high as you can get.. 2 0 obj I won't bore you with all that so the first portion of this still only shows up to the 4th multiple. 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. x 4 in. , Most matching problems occur when the antenna system PVC Junction Box(Home Depot), 1 x 1/2 in. 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? Each vertical blue line represents an amateur radio band. The WSPR map is so dense it looks like the US and Europe are just big blobs of color. Free Postage. I wrote a small C program that does just what Jack did, butI used the band edges. 74 0 obj <>stream is helpful if you're in a hurry to get on the air, read up on the topic 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. I used the RigExpert Zoom AA-55 to test VSWR of the 49:1 unun impedance transformer. these are the worst lengths and you want to be as far from colored Lengths to avoid are not always the same as End Fed Antennas. config file by typing gnuplot rw.gnu. /ProcSet 7 0 R >> Liquidtight NM 90-Degree Connector(Home Depot). 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. % Computer Help I sent him the link to the 49:1 unit to get his feedback. 22.00 + 5.00 Postage. Change the program to use 423 if desired.) it is easy to pack and easy to install. document.getElementById("copyright_year").innerHTML = new Date().getFullYear(); 80m up, W3EDP's 84' antenna, 17' counterpoise is probably the way to go. Repeater Basics So a 49:1 impedance transformer is needed to match the 50 ohms of the coax at the feed line. Theme designed by Papathemes. (QST, Oct 1926, "The Length of the 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. endstream At multiples of half wavelengths of the /* Ad banner 160 x 600 */ Just add or subtract as needed a little at a time toget the best compromise. Both were on 20 meters at 97 watts, Icom 7300. bands you're intested in in a vector like the example below, by typing. This will be for an eyehook in order to provide strain relief for the radiator wire. X:nzf4p:t;r }~_HOZcX:^$* J^XZuu|"nX/Wkw0hA>y1(z2+v_Xzu[/:^$*m*>hk_:+c{ The short piece is for the primary winding of the transformer, and the long piece is for the secondary winding of the transformer. Superglue 2 toroids together. This Balun Designs unit is replacing an MFj 1982 HP EFHW balun that was DOA when it arrived last May. For calculating the length of a half wave in metres, I use 141 (MHz) for wire elements. You also 6 Screws/ Nuts/ Washers/Wing Nuts And Ring Connectors, 1 X Mica Capacitors 100pF 500V 5%(Mouser Electronics), 1 x 4 in. 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. The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. Quantity: Sold individually. Figure 2 Schematic of the 9:1 voltage unun . Coverutilizes integralneoprene gasket for weatherproof integrity. 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. The "9:1 UNUN" are for random length wire antennas fed at the end. for your country and favorite modes of operation. 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. 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).
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