(QST, Oct 1926, "The Length of the EFHW unun Resonant Long Wire 49:1 Transformer With BNC or SO-239 | Mobile Phones & Communication, Radio Communication Equipment, Antennas | eBay! You have to give up a band or two, like 60m and 6m, as Continue on winding the long wire through the toroid to complete loops 3 through 14 as shown in the schematic below. Let the now free end of the short wire hang down from the toroid. it is easy to pack and easy to install. 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. uR5ucE`_aksLjYT=hzRa]JucX7d}|'}`XRa>X June 8, 2022 at 9:17 am. x][~ XwiH:99gn`1-wz;n[VbW7JH4D]>}>y/D_^7,yyx}s*nveo>mn|6k7GMY4%" M)?O|'opw8o1\5JNe:9hTc5@Ik~aE%O^0$ 0E 'BX2?R!t&^E"3oqbW |${boEU>jU:]bQW?4, u1'^`oQ_4E 0~y L^'y}-RHV8L KSZ?mF4lTv'r^mF|":e}?VdTm7bGR]PchDpb*{*HGJ-m)bC!EX"iM%8L7O7-=jcn+D{_' I HH~v70J^9$.7m]knq)L(UQ%OrK:nn!8*EP Having the option to switch rapidly between 49:1 and 64:1 should prove to be a really nice feature.. 3 0 obj 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). In fact, the 9:1 unun that I built is actually an autotransformer. these are the worst lengths and you want to be as far from colored Drill out holes in the designated bottom of the electrical junction box for the SO239 chassis mount. stream all US ham bands. You can get good loading and low swr on sometimes 2 or 3 bands, but one or more of the bands thatyou want, just will not cooperate with an swr that can be adjusted with the "tuner". If the transformer is used with an externaltuner in conjunction with a single wireantenna typically 130-135 feet in length, power should be reduced on those bands that show an SWR above 1.6 to2:5 withoutthe tuner. You'll want to have that wire up as high as you can get.. (The numbers aboveare a great start, thanks to Jack and Mike! Each vertical blue line represents an amateur radio band. /Height 752 I'm not saying aliens are in the radio, but aliens definitely are in the radio. excellent page for EFHW info - or, addressed below, to cut the wire This is a followup video to #344 where I assembled the 49:1 UNUN kit from HF-Kits / ARRL. Start winding the toroid with the twisted wires at loop #1 (see schematic below). Lengths of a half-wave or multiple must be avoided. 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. A small ring terminal for 14ga wire that fits these screws would be helpful too. Modify bands and 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 antenna, which works on 10, 15, 20, and 40 meters, has a very high impedance of around 2,500 Ohms. . 4 0 obj SSTV Reading Room (wlSR9dJ_x%+VHX4FRr 3>;g^x%g'wkJu,i~#Q"2|WGf[!_m]#&1$)R.{--" 'dGO;=_B$T}". That is the 10th multiple of a half wave on 15 meters. So for 80 meters (say 3.525 MHz) this gives you about 133' of wire. Kj8~q7c? Here Is a 250 Watt Home-Brew That I Made In about an Hour. 3 to31 MHz - up to 1kW intermittent (50% duty cycle). 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. The table below represents half wave lengths and multiples that you DO NOT WANT TO USE! This design is excellent for matching both long and short length wire antennas for multiband use. >> Just add or subtract as needed a little at a time toget the best compromise. <>>> "Just received my new 64131 yesterday and was anxious to see how well it performed. http://udel.edu/~mm/ham/randomWire/. Swr usually is all over the place and the tuner will just not do it's job. 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. Custom mix low permeability ferrite by Fair Rite Products for maximum bandwidth. Here is an ARRL Lengths to avoid are not always the same as The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. The length should be calculated based on the lowest frequency to be worked. Typically unbalanced = 50/75 ohms too unbalanced = 450/675 ohms. Ham Hints This project assembles a 49:1 ferrite-core ("FT") type #43 transformer that matches 50 ohm input to 2500 ohm end fed antenna. One is for the top of the box so that it can be hung up. 9:1 or 49:1 unun for end-fed long/random wire? Theme: Newsup by Themeansar. endobj That meant calculating all the way to 32 multiples of a half wave on 10 meters. and experiment. V#X~[Z?\ZcX:-Y?&Y?IqTnayZ{jTZOub}=UTWu1G>o.,RaT c=W>:sECXTkc=X You also 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. "Can you please recommend schematics that are designed to tune setups like these? $119.95. endstream endobj startxref random wire page. /Subtype /Image are blocked out because an antenna should be at least that long. frequencies for your country or favorite modes. Advertising Info Turns 1 through 14 are secondary windings (the long wire). "Here's the word on random-wire antennae.". IMG_2.jpg Step 2: Take the 6 feet of 18 gauge enameled copper wire, measure 11" from one end and fold it back. wire is at least 1/4 wavelength. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. This is not exactly a 1/2 wavelength in free space, but works for wire as it has a different velocity factor than "air". Change the program to use 423 if desired.) Designed for use with single wire unbalanced antennas, this new addition is small, compact and perfect for quick portable/emergency installations. So a 49:1 impedance transformer is needed to match the 50 ohms of the coax at the feed line. HF Underground wiki Radio Hobbyist technical blogHFU Discord EuroPirate ChatPropagation DataTeamspeak Server, TDK CXA-2090 LCD Inverter Module New Old Stock USA Seller $19.99, Shortwave Pirate Radio In North America And Around The World, And Other Signals That Go Bump In The Night, Login with username, password and session length. 9:1 Unun 1.5-54MHz 2kW 9132S. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. This Balun Designs unit is replacing an MFj 1982 HP EFHW balun that was DOA when it arrived last May. Each winding is counted when the wire enters through the center hole of the toroid. /BitsPerComponent 8 << Computer Help google_ad_slot = "1982258389"; I say run what you got and don't worry about it. Part List: Ham Radio Videos! . var sc_invisible=1; The following wire connections do not need to be made in the order I described. 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. Re: 9:1 or 49:1 unun for end-fed long/random wire? Designed for those who want the maximum isolation and choking across the full HF spectrum. 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. 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. 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). used by hams for dipole lengths. Picture Information. 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. 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? 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. high the other 1.5m (4.5feet). Drill a hole in the top for an eyehook (to be used to secure the unun to whatever it is you want to hang it from.). ones I imported my spools from the US, but I have seen them on Ebay in the UK. WwS`8o}=n,pjhzRa]Ju/Ru ni4=UvZ:u9*@ Xz+zZcXm}i[Z;Z>.u!*eQVjucXeqYZnSJu)U[n>>KXzZ.Lz sqxcGj]%q}i6=-?YTlnZXV6}=U >5`ZNxChzRa]JU.6TVr6a] 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. Here I show finalizing the antenna, getting it in the air, and run. 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. %PDF-1.5 Antenna Safety! 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. Tune Around! /ProcSet 7 0 R >> The Short Answer Would Be That an UnUn Is a "UN balanced to UN balanced" matching transformer. I only used two screws instead of four. When do you use a 1:1, 9:1 or a 49:1 balun? Privacy Policy You have to stay away from a half wavelength on any frequency. 3 0 obj Wire-Lengths-for-9-1-ununs.pdf Created Date: 12/12/2022 11:20:42 AM . 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 /CreationDate (D:20221212112042) Suggested wire lengths for 1-61 MHz operation (measured from Bullet wire point): Bands Covered (meters) Wire Length (feet) Minimum Coax Length (feet) 40-30-20-15. A way of connecting the analyzer to the transformer. Shortwave Listening 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. So those are the numbers above thatwe have to stay as far away from as possible when building a long-wire antenna. One end goes straight into the While I have not done so yet, I plan on gluing the test cap to the back of the junction box. I have not done this yet. Just add or subtract as needed a little at a time to get the best compromise. 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). 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. Hertz Antenna" shows in line 2 of the table that a similarly installed This calculates to 4.2 m or 14 ft for an 80m end-fed. Post Reviews Feeling a bit too lazy to calculate that by hand, however, I wrote a Use with other lengths can potentially damage the transformer depending on power level in use. The fewer bands, the fewer high impedance regions to avoid. 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. (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. The graph below shows lengths to avoid for different collections of bands. The Nelson antenna 9 to 1 unun did the trick. STORE var sc_security="1df091cc". 35-43, 49-63, 70-85. So is an essential piece of gear to have. (Note: I am not satisfied with this part of the project, so I will describe it here briefly. Powered by BigCommerce. JavaScript is disabled. HF & Shortwave There are numerous configurations available online that will accomplish this on multiple bands (Google search "end fed half wave antennas"). The ratio doesn't need to be 49:1 2,400 ohm either, other ratios will transform to other impedance. In other google_ad_height = 600; We are working every day to make sure our community is the best Radio Hobbyist's site. stream so that it is not a halfwave multiple of any frequency you want to use. 35-45, 54-64, 67-77. 0$Ve 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. the program as I did, above, for my K1. Vhf and Up something as high as you can find. endstream q 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). We recently found some good information about random wire lengths that you should and should not use. /Length 10 0 R