49:1 unun wire lengths

35-43, 49-63, 70-85. Save program output in file named 'f', and use 10m or 33' long. I won't bore you with all that so the first portion of this still only shows up to the 4th multiple. Midi Music Click to enlarge. I sent him the link to the 49:1 unit to get his feedback. You can add your own wire or get the complete product from this link EFLW-3K antennas. << 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). Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. This project assembles a 49:1 ferrite-core ("FT") type #43 transformer that matches 50 ohm input to 2500 ohm end fed antenna. 35. Here Is a 250 Watt Home-Brew That I Made In about an Hour. <>/Metadata 239 0 R/ViewerPreferences 240 0 R>> Cut a 4 foot length of AWG #18 enameled wire. 9:1 Unun EF Random Long wire matching Transformer with BNC or SO-239. The length of a half wave antenna is calculated using the following formula: L (ft) = 468 / f (freq in mhz). 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. endobj K1S Valentines Are (Almost) Out The Door! A few more comments about this 49:1 autotransformer EFHW design. thank you. 73. JACK, VE3EED Again, the bands are USA, so change them wire is at least 1/4 wavelength. endobj When on the trail, at Field Day, or whenever a good antenna is We do not encourage any radio operations contrary to regulations. the C code, in Matlab or Octave get a plot by simply putting the "Just received my new 64131 yesterday and was anxious to see how well it performed. The vertical (y-) axis shows the VSWR and the horizontal (x-) axis shows the frequencies. Theme designed by Papathemes. 40-30-20-17. Even better would be shortening to 53'. /ColorSpace 11 0 R There are so many new frequencies to stay away from, that it gets pretty tricky for the longer wires. doing the initial 468/f on C and D scales. For instance, to work 40m be sure the antenna is at least 10m or 33' long. At this point, Ive only used the 49:1 tap, but plan to take the 64131 whenever I operate portable. The length should be calculated based on the lowest frequency to be worked. Antenna") is an 84' long end fed and a 17' long counterpoise (6.5' for 20m). 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. 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 . 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 A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. endobj Repeater Basics The other is to provide strain relief for the antenna wire). 32.00. %PDF-1.5 (Note: I am not satisfied with this part of the project, so I will describe it here briefly. This type of antenna is very easy to install because there is no need . UJM-49-1 $56.99 Save up to 6% when you buy more. I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. 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). Here's a list of recommended lengths of wire to use with a 9:1 unun. Because I'm more visually oriented I then plotted the many overlapping "red zones" and ended up with the page at: which got me thinking. (Originally published February 22, 2021). "Can you please recommend schematics that are designed to tune setups like these? JavaScript is disabled. /Subtype /Image . That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . /CreationDate (D:20221212112042) In other So a 49:1 impedance transformer is needed to match the 50 ohms of the coax at the feed line. At multiples of half wavelengths of the SBULLET-9U-1500. <> I purchased a MFJ-16010 Random Wire Tuner and an LDG RU 1:1 unun. Lengths to avoid are not always the same as Care to buy us a beer? It may not display this or other websites correctly. Notice from column f that there is no length giving low impendance for 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. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. Feeling a bit too lazy to calculate that by hand, however, I wrote a here are values for CW portions of the USA 40-10m with a 49:1 Unun. Please note that I will not be describing the construction of the antenna wire radiator here. /Kids [ 4 0 R ] 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. One single wire, no solder connections,very simple.all the way from the tuner to the end support. 6 0 obj Enclosure Depth: 1.250 in. 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. SSTV &nb However, the list has been revised and is good for wires as long as 500 feet. Here Is a 250 Watt Home-Brew That I Made In about an Hour. Coverutilizes integralneoprene gasket for weatherproof integrity. 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. 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. this answers on D - one setting. %%EOF 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). 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. Let's have a look at a few details on how to build a 49:1 impedance . Picture Information. This is a followup video to #344 where I assembled the 49:1 UNUN kit from HF-Kits / ARRL. So for example 80m could range in length from 120 to 133 feet. 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 standard recommendation (see QST, March 1936, p. 32, "An Unorthodox 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 management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. You are using an out of date browser. The short piece is for the primary winding of the transformer, and the long piece is for the secondary winding of the transformer. Longer wire is always more 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 . On our next windy free day, AA1F and . 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. Antenna Design I imported my spools from the US, but I have seen them on Ebay in the UK. Some of these numbers are too close to squeeze in between them. A success! Swr usually is all over the place and the tuner will just not do it's job. So is an essential piece of gear to have. For instance, to work 40m be sure the antenna is at least 20/40/17m. Typically unbalanced = 50/75 ohms too unbalanced = 450/675 ohms. (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. stream We recently found some good information about random wire lengths that you should and should not use. (QST, Oct 1926, "The Length of the Q /Type /Page /Count 1 3 0 obj 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. Designed for use with single wire unbalanced antennas, this new addition is small, compact and perfect for quick portable/emergency installations. presents an extremely high impedance to the tu Wire lengths for the 4:1 ratio in models 4130, 4132, 4134, 4932 and 4935. The Short Answer Would Be That an UnUn Is a "UN balanced to UN balanced" matching transformer. You will note that when comparing my results with VE3EED that some of the results are a bit different. The unun was floating at about 15 feet above ground. 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. Meet 'Balun One Nine', a small, cost-effective balun. The 49:1 impedance transformer will help you bring down the high impedance of your resonant EFHW antenna to almost 50 Ohm. I have not done this yet. The kit includes the parts needed to construct a 49:1 impedance matching network, which will transform the impedance to 50 Ohms, which will suit most transceivers. I did not want to put the transformer in the housing until I tested it. Y &lD30. Wire lengths for the 4:1 ratio in models 4932 and 4935. /MediaBox [0 0 748 752] 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. 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. tuner the colored bands below are the best lengths as long as your I've made contact with several folks across North America in my 6 months as an amateur but getting to Europe flipped a switch and I'm afraid this amateur radio thing is going to be addicting. The QRP End-Fed Half-Wave Antenna 49:1 Transformer Building a great impedance transformer for Ham Radio end-fed wire antennas. Enclosure Height: 5.000 in. Best SWR was . 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. Privacy Policy Proudly powered by WordPress FCC Information The graph below shows lengths to avoid for different collections of bands. This design is excellent for matching both long and short length wire antennas for multiband use. ?7{*. 6 Screws/ Nuts/ Washers/Wing Nuts And Ring Connectors, 1 X Mica Capacitors 100pF 500V 5%(Mouser Electronics), 1 x 4 in. stream End Fed Antennas. Be sure to review the various lengths in the link below to obtain the lowest SWR across most if not all HF bands. 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. Here is an ARRL Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. . I use this 8010 EFHW at home, too. 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. Twist the short and long wires together starting at an end of each wire. . 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. To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. >> Ultimately, this housing works fine, but it is heavy and clunky.). Quantity: Sold individually. If you want all the bands from Thus a 1/4 wave for 20m@16ft, 40m@33ft as examples are not going to work. Downward impedance transformation by factor of 49. , This is a partial reprint (with permission) of an excellent series of articles published by KV5R Therefore, we came up with the following numbers to avoid (IN FEET): These lengths in the table beloware the culprits that cause all of the trouble when using random lengths. SWR was good after cutting the wire to appropriate length. the program as I did, above, for my K1. [ /PDF /Text /ImageI ] "I received my third balun from Balun Designs this afternoon. End Fed Half Wave Antenna Coupler Schematic - 7-30MHz. /Width 748 I made just a touch over 100 QSOs today with the new unit. That's it in a nutshell..or is it? used by hams for dipole lengths. endobj Moving the pot up and down gives a feel for the SWR versus antenna impedance sensitivity. Balun Designs. random wire should use 423/f. is helpful if you're in a hurry to get on the air, read up on the topic , Reprinted with permission of Hamuniverse, this is an excellent explanation of SWR and how to best me In another life, I could have been a telephone engineer. Both were on 20 meters at 97 watts, Icom 7300. /Type /XObject Thanks for your answer,I will probably go with the 9:1 then. 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. | Anyway, an old friend mentioned 'MyAntenna.com' but they were closed for the summer. 4 0 obj 40-30-20 . Stacked coreswithwinding configured as 49:1auto transformer. Continue on winding the long wire through the toroid to complete loops 3 through 14 as shown in the schematic below. Experimenting by slightly changing the wire length (+ or-) is encouraged to provide best overall performance. Even easier than You have to stay away from a half wavelength on any frequency. Tweak the antenna length if necessary and then maybe adjust the turns ratio again. VSWR analysis of the antenna in the field showed that VSWRs between 3-5.5 from 40M to 10M. This was 9m vertically metres up a fishing pole and then about 5.8m out. x 4 in. Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. >> var sc_security="1df091cc". 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. Drill another hole in the same side as the antenna radiator wire mount hole. The table below represents half wave lengths and multiples that you DO NOT WANT TO USE! A VSWR sweep of the unun after adding a 100pF capacitor shows an SWR <5:1 from 160M to 10M. While these lengths have been shown to work well on many bands, which Re: 9:1 or 49:1 unun for end-fed long/random wire? %PDF-1.5 % wire lengths less than 1/4 wavelength of the lowest desired frequency http://udel.edu/~mm/ham/randomWire/. Having the option to switch rapidly between 49:1 and 64:1 should prove to be a really nice feature.. 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. SEARCH hbbd```b``^ "Cs;D2 I*`0D;+EVUHy`qml0{YVw`b0i DvkAh |"w I2% ?W%@Fg`` 6 The key is you want to stay at least 1/2w long but not near 3/4w for any band of interest. random wire page. The matching unit The impedance at the end of a half wave antenna is somewhere between 2000-5000 Ohms. (The numbers aboveare a great start, thanks to Jack and Mike! /CropBox [0 0 748 752] So for 80 meters (say 3.525 MHz) this gives you about 133' of wire. My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. Hopefully these random wire length calculations will help us all make this "easy" antenna work better! google_ad_client = "ca-pub-9377297764300878"; If you want a single band portable antenna you can mount pretty much however, look up this design. 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. it is easy to pack and easy to install. well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) Our newdesign isperfect for matching both long and short length wire antennas for multiband use. /Pages 3 0 R 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. >> 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. excellent page for EFHW info - or, addressed below, to cut the wire 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 Picture 1 of 9. /Im0 Do u?X`f0&/Ri;W0Tn_*TX:ug but instead of the Jaycar core, we used an Amidon FT-240-43; anyhow, we also followed the UnUn with a 1:1 guanella choke and boxed everything, at that point, we . 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.

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