STORE Enclosure Height: 5.000 in. 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. 40-30-20 . One single wire, no solder connections,very simple.all the way from the tuner to the end support. endobj
Turns 1 & 2 are primary windings (the short wire). You also Hi guys,not really hfu related,but I tought I might ask here as I have my account. << Each winding is counted when the wire enters through the center hole of the toroid. 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). You also want the antenna to be at least 1/4 wavelength long for each band you plan to use. Work all bands from 80 through 10 on it. Cut a 4 foot length of AWG #18 enameled wire. %%EOF
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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. Save program output in file named 'f', and use 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. "Here's the word on random-wire antennae.". End Fed Antennas. 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 . Wire lengths for the 4:1 ratio in models 4932 and 4935. This will be for an eyehook in order to provide strain relief for the radiator wire. 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. for your country and favorite modes of operation. 33 ft #18 insulated copper wire (20m half wave), Counterpoise: 1 meter coax (0.05 x wavelength) connected between 64131 and Balun Designs 1115d Isolation /Choking balun, 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. I use this 8010 EFHW at home, too. However, the list has been revised and is good for wires as long as 500 feet. 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? 1. The length of a half wave antenna is calculated using the following formula: L (ft) = 468 / f (freq in mhz). 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. Electronics Code Practice 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. One end goes straight into the Y &lD30. 40-30-20-15m bands for my 4 band Elecraft K1 qrp rig. 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. 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. While I have not done so yet, I plan on gluing the test cap to the back of the junction box. The matching unit The impedance at the end of a half wave antenna is somewhere between 2000-5000 Ohms. /CreationDate (D:20221212112042) <>
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 "RANDOM WIRE" HF DIPOLE 9:1 ANTENNA RELACEMENT ELEMENT ONLY $28.99 Save up to 6% when you buy more. It will be good for 15m, and 10m. $1YacO5Q}YC\>qZ } Winding 1:64 Matching Auto Transformer on the FT240-43 core. /ProcSet 7 0 R >> ), Note that Jack, VE3EED,went SK several years agohe will be missed. endstream frequencies for your country or favorite modes. We do not encourage any radio operations contrary to regulations. 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 a 250 Watt Home-Brew That I Made In about an Hour. To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. /* Ad banner 160 x 600 */ 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. 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. Typically unbalanced = 50/75 ohms too unbalanced = 450/675 ohms. Tune Around! j#f5(fk0?P[polEo5b2-/oVZu1Qo-I6C/M@TbddPc#cdZZ|7+|o{}!F#?Go7ju|?wwgow/c2/W-m~~hn[S29OU}}r7lc]wsw[shS[#qbrrK[7*0,Xv{k+o {=*vo S__O~*=y/zk75O?yjCnXS{`~Ii'c_GxN. 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 . As typically Product Reviews 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. %
Power handling is 100 watts CW / SSB & 25W Data modes. 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. 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. SSTV On our next windy free day, AA1F and . <>/Metadata 239 0 R/ViewerPreferences 240 0 R>>
About Hamuniverse Connect this ring terminal to one of the SO239 chassis bolts. Proudly powered by WordPress There are numerous configurations available online that will accomplish this on multiple bands (Google search "end fed half wave antennas"). 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. JavaScript is disabled. 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). Theme: Newsup by Themeansar. endobj
endobj I made just a touch over 100 QSOs today with the new unit. x@ The idea 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. You can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. Free Postage. Click to enlarge. Here's a list of recommended lengths of wire to use with a 9:1 unun. Privacy Policy 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. Dimensional Drawing of Standard Enclosure, 1:1 Common Mode Choke / Noise Suppression, Core Material Selecton for Baluns and Ununs, Antenna Matching Problems When Using Ladder Line or Open Wire Feedlines, Model 4932 - 4 & 9:1 Unun 1.5 - 54MHz - 2kW, Model 49130 - 49:1 - 80-10m EFHW - 200 watts, Model 64131e - 64:1 & 49:1 - 80-10m EFHW - Up to 1kW, Model 4116 - 4:1 Hybrid Balun 1.5 - 54MHz 3kW, Model 9130sw - QRP 9:1 Unun 1.5 - 54 MHz - 300 watts, Model 1115d - Max Choking 1:1 Balun, 1.5-54 MHz, 5kW. &nb endobj Please note that I will not be describing the construction of the antenna wire radiator here. This antenna, which works on 10, 15, 20, and 40 meters, has a very high impedance of around 2,500 Ohms. %PDF-1.5
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The length should be calculated based on the lowest frequency to be worked. This is a followup video to #344 where I assembled the 49:1 UNUN kit from HF-Kits / ARRL. 32.00. /Height 752 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. . The bandwidth where SWR was below 2:1 was about one MHz. I made one without doing this and it didn't work so well. So for example 80m could range in length from 120 to 133 feet. 1 X FT240-43 Ferrite Toroid Core 43 Material(Mouser Electronics), 1 X SO-239 UHF PANEL JACK S/CUP SO-239(Mouser Electronics), No. 7 0 obj I swept the VSWR of the unun and resistors as described from <1 to 55MHz. UJM-49-1 $56.99 Save up to 6% when you buy more. 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. Downward impedance transformation by factor of 49. Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. Ham Satellites Repeater Builders What these lengths are depend on your tuner and also the wire's surroundings and also the ground system. often can't match it. SO-239 connectors are silver plated with Teflon insulation. 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. 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. Reading Room A so-called random wire antenna is an end fed antenna. That meant calculating all the way to 32 multiples of a half wave on 10 meters. the C code, in Matlab or Octave get a plot by simply putting the He knew that in order for the tuner to "see" a fairly low swr to work within it's range,that the antenna had to be NOT A HALF WAVE ON ANY FREQUENCY that we wanted to us, because a half wave will give us a very high impedance and the resultingswr into a 50 ohm transmitter! You'll want to have that wire up as high as you can get.. presents an extremely high impedance to the tu 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. 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. This is not exactly a 1/2 wavelength in free space, but works for wire as it has a different velocity factor than "air". So, having nothing better to do one day, I re-did the calculations going out to 500 feet. Just an FYI that I thought you might be interested in. rig, often with no feedline, and the other end in the air attached to Antenna") is an 84' long end fed and a 17' long counterpoise (6.5' for 20m). <>>>
4 0 obj This is the latest and greatest transformer design for End Fed Half Wave (EFHW) antennas. Jack, VE3EED - SK. <>
x 4 in. We hoisted the free end of the antenna wire approximately 30 feet into a tree. Designed for those who want the maximum isolation and choking across the full HF spectrum. 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. The Nelson antenna 9 to 1 unun did the trick. "Can you please recommend schematics that are designed to tune setups like these? 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 not a good choice for working lower bands from a too short wire, that is, if you have cut your wire to a 20m halfwave, it ain't much punkin' for 40m, 80m, or 160m. For calculating the length of a half wave in metres, I use 141 (MHz) for wire elements. want the antenna to be at least 1/4 wavelength long for each band you For typical tuners built into a rig, The WorldwideDX Radio Forum was originally established in 2001. A 50 foot run of RG-8X coax connected the antenna into the LDG Z100-plus tuner and then a Yaesu FT-891A transceiver. After winding #2 is made and extends down the backside of the toroid, untwist the wires. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. endobj He had heard good things about 'Balun Designs' so he recommended you. When on the trail, at Field Day, or whenever a good antenna is For best results, use the Wire Length Feet 1.8 MHz 3.7 MHz 5.3 MHz 7.1 MHz 10.1 MHz 14.2 MHz 18.1 MHz 21.2 MHz 24.9 MHz 28.5 MHz 50.1 MHz 22.00 + 5.00 Postage. 2 0 obj
This design is excellent for matching both long and short length wire antennas for multiband use. plan to use. One is for the top of the box so that it can be hung up. 2 0 obj 6 0 obj << 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. Twist the short and long wires together starting at an end of each wire. 9:1 or 49:1 unun for end-fed long/random wire? 1 0 obj
The trick, therefore, is either ?7{*. Advertising Info A few more comments about this 49:1 autotransformer EFHW design. /CropBox [0 0 748 752] 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. 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. It is important to use a counterpoise. These dimensions were derived from modelling the antenna in EZNEC. 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). A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. Contact $119.95. endobj I say run what you got and don't worry about it. Here Is a 250 Watt Home-Brew That I Made In about an Hour. The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. x[q;`&z`uAlo#V@;hvOYt, @*Ys~_W_~W_aw_
p[N+}[t-^oLy}xz>7/~c|ZZt75;kN^=>Y+_~|b~"m*tw>xG=x6Qwz|xvz- Using a 49:1 transformer shoot for the best 50 match @ appx 2450 load over your working frequency bands. The fewer bands, the fewer high impedance regions to avoid. Kj8~q7c? At multiples of half wavelengths of the Make sure the beginning few inches of twisted wire is not involved in the winding (i.e., just hanging down from the toroid). "I received my third balun from Balun Designs this afternoon. When do you use a 1:1, 9:1 or a 49:1 balun? the program as I did, above, for my K1. SBULLET-9U-1500. 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. InJack's own words. I used 2000 and 1000 ohm resistors in series connected to the proper unun wires with alligator clips for a total of 3000 ohms. HF & Shortwave are easily converted to half wavelengths by the famous 468/f generally 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. RFI Tips and Tricks 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. This undesired reflection of RF power back toward the transceiver is identified as a high voltage standing wave ratio (VSWR or SWR). 1936 article, however, fall in line with 468/f and so is used here. Usually any wire length that is non resonant on the band or bands desired will work with the 4:1 ratio. A png image named g.png will be created. bands you're intested in in a vector like the example below, by typing. . This homebrew 49:1 impedance transformer is the heart of any EFHW antenna you will build, most of the time. 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. /BitsPerComponent 8 Ultimately, this housing works fine, but it is heavy and clunky.). 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. 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. I attached the toroids to a PVC DWV test cap with 3 cable ties. 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. /Type /Pages 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. 2 0 obj
(QST, Oct 1926, "The Length of the The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. var sc_invisible=1; An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. 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). You have to stay away from a half wavelength on any frequency. 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. Part List: 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. A VSWR sweep of the unun after adding a 100pF capacitor shows an SWR <5:1 from 160M to 10M. /ColorSpace 11 0 R