49:1 unun wire lengths

InJack's own words. this I say run what you got and don't worry about it. I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. endobj 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. 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.). /BitsPerComponent 8 . Vhf and Up 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. Just add or subtract as needed a little at a time toget the best compromise. This calculates to 4.2 m or 14 ft for an 80m end-fed. /Parent 3 0 R I have found this calculation to work well, however it depends on many factors such as wire used, location etc. The 49:1 impedance transformer will help you bring down the high impedance of your resonant EFHW antenna to almost 50 Ohm. 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. The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. here are values for CW portions of the USA So after much frustration..down it comes and you go on to a totally different type of antenna.all that time just wasted inyour opinion..until now! A small ring terminal for 14ga wire that fits these screws would be helpful too. 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. 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). The ratio doesn't need to be 49:1 2,400 ohm either, other ratios will transform to other impedance. /Type /Page 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. You have to stay away from a half wavelength on any frequency. Usually any wire length that is non resonant on the band or bands desired will work with the 4:1 ratio. Generally an EFHW will be in the range of 2,000 to 5,000 ohms at the very end of the dipole when resonant. 40-30-20 . Thanks for your answer,I will probably go with the 9:1 then. stream 9 0 obj JavaScript is disabled. high the other 1.5m (4.5feet). If the choices are. 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. . Both were on 20 meters at 97 watts, Icom 7300. Electronics Cut the center conductor wire (free untwisted end of short wire) of the unun to the correct size, scrape the enamel insulation off of the free end with a box cutter, and solder it to the SO239 connector. $119.95. Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges. SO-239 connectors are silver plated with Teflon insulation. often can't match it. 35. bands you're intested in in a vector like the example below, by typing. Please note that I will not be describing the construction of the antenna wire radiator here. /MediaBox [0 0 748 752] 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). License Study 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). So I just wanna say thank-you!! 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. 4 0 obj 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 The First Thing New Hams Often Ask:What Is An UnUn? wire lengths less than 1/4 wavelength of the lowest desired frequency 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 used 2000 and 1000 ohm resistors in series connected to the proper unun wires with alligator clips for a total of 3000 ohms. x 2 in. This article details the construction of the transformer. UJM-49-1 $56.99 Save up to 6% when you buy more. 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. 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. End fed 9:1 58ft wire and 17ft counterpose wire touching ground. Tweak the antenna length if necessary and then maybe adjust the turns ratio again. 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. shown in the column e. var sc_project=8077274; Stacked coreswithwinding configured as 49:1auto transformer. <> /Kids [ 4 0 R ] The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. Cut a 4 foot length of AWG #18 enameled wire. It's an efficient way to get all the multiples The vertical (y-) axis shows the VSWR and the horizontal (x-) axis shows the frequencies. My homemade 49:1 EFWH with a 60 wire (cut for 40M) would do just fine! The WorldwideDX Radio Forum was originally established in 2001. This article explains why the use of mix 43 for HF applications is almost always a mistake. /Type /XObject /Count 1 This homebrew 49:1 impedance transformer is the heart of any EFHW antenna you will build, most of the time. In stock . You will note that when comparing my results with VE3EED that some of the results are a bit different. Multiples are on C and %PDF-1.5 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. 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. >> /Creator (XnView) endobj , This is a partial reprint (with permission) of an excellent series of articles published by KV5R End Fed Half Wave Antenna Coupler Schematic - 7-30MHz. The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? Here Is a 250 Watt Home-Brew That I Made In about an Hour. Do what works best! Midi Music One end goes straight into the I purchased a MFJ-16010 Random Wire Tuner and an LDG RU 1:1 unun. The key is you want to stay at least 1/2w long but not near 3/4w for any band of interest. << W3EDP's results in the above referenced At multiples of half wavelengths of the Custom mix low permeability ferrite by Fair Rite Products for maximum bandwidth. 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 Contact I sent him the link to the 49:1 unit to get his feedback. Picture Information. Presented for your consideration by Jack, VE3EED. Start winding the toroid with the twisted wires at loop #1 (see schematic below). "Just received my new 64131 yesterday and was anxious to see how well it performed. (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. 748 0 0 752 0 0 cm K1S Valentines Are (Almost) Out The Door! Hertz Antenna" shows in line 2 of the table that a similarly installed https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. Thank you so much for such a great product! /CropBox [0 0 748 752] 5 0 obj Recommended wire lengths for Unun models 9130, 9132 & 9135 Table shows typical SWR relative to installed wire length. (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. 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. Clansman End Fed Long Wire Antenna Used. Wire lengths for the 4:1 ratio in models 4932 and 4935. Ham Radio News! something as high as you can find. >> Solder a the 100pF capacitor between the center conductor wire and ground wires. You also want the antenna to be at least 1/4 wavelength long for each band you plan to use. 40-30-20-15m bands for my 4 band Elecraft K1 qrp rig. This design is excellent for matching both long and short length wire antennas for multiband use. Lengths to avoid are not always the same as I included the tools I used to analyze the transformer as well; this is only necessary if you are interested in analyzing your project. Enclosure Height: 5.000 in. Here Is a 250 Watt Home-Brew That I Made In about an Hour. Hope it's clear now, if not. IMG_2.jpg Step 2: Take the 6 feet of 18 gauge enameled copper wire, measure 11" from one end and fold it back. This transformer is designed to be used with an end fed half wavelength of wire only. 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. SEARCH X:nzf4p:t;r }~_HOZcX:^$* J^XZuu|"nX/Wkw0hA>y1(z2+v_Xzu[/:^$*m*>hk_:+c{ It is important to use a counterpoise. 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 . Liquidtight NM 90-Degree Connector(Home Depot). 35-45, 54-64, 67-77. The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. 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. Hi guys,not really hfu related,but I tought I might ask here as I have my account. (QST, Oct 1926, "The Length of the these are the worst lengths and you want to be as far from colored See the picture below. V#X~[Z?\ZcX:-Y?&Y?IqTnayZ{jTZOub}=UTWu1G>o.,RaT c=W>:sECXTkc=X 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 config file by typing gnuplot rw.gnu. /Type /Pages unavailable, a random wire can save the day, but it is important to A so-called random wire antenna is an end fed antenna. A success! 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. 0 35. The QRP End-Fed Half-Wave Antenna 49:1 Transformer Building a great impedance transformer for Ham Radio end-fed wire antennas. Step 1: Drill holes for and install the SO-239 or BNC connector, the stainless steel machine screw antenna connector and the ss machine screw ground connector. . You are using an out of date browser. The fewer bands, the fewer high impedance regions to avoid. /CreationDate (D:20221212112042) About Batteries endstream endobj startxref results. This Balun Designs unit is replacing an MFj 1982 HP EFHW balun that was DOA when it arrived last May. Windings are inserted into Teflon tubes increasingtotal breakdown to 10,000 volts. and leave the unun on the ground. /&KWA7{L=D]g0Z!F9;V{zL[h-D,u(.9rg(RHI{f t*C/?? Shortwave Listening Tune Around! 3 to31 MHz - up to 1kW intermittent (50% duty cycle). Cannon". 1. Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 1500 Watts, End Fed Antennas. 1 0 obj He was so impressed that he purchased a 9:1 unit from you, his will be delivered Saturday. x@ %PDF-1.7 Use with other lengths can potentially damage the transformer depending on power level in use. Use only the white gaps for your antenna lengths, and if What these lengths are depend on your tuner and also the wire's surroundings and also the ground system. bands as possible. The bandwidth where SWR was below 2:1 was about one MHz. which got me thinking. Computer Help (Center fed is so appealing because you avoid this.). hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r I have included a screenshot showing the stations that reported spotting my 200 mw beacon over the last 16 hours. 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. Each winding is counted when the wire enters through the center hole of the toroid. For example, For typical tuners built into a rig, The Nelson antenna 9 to 1 unun did the trick. Even easier than 2 0 obj Drill another hole in the same side as the antenna radiator wire mount hole. An Unun is used to match an unbalanced line to another unbalanced line. Usually any wire length that is non resonant, like those shown above, will work with the 4:1 ratio. /Width 748 ", KiwiSDR Online Radio - 500 ft Northeast Beverage, KiwiSDR Online Radio - 400 ft South Beverage, KiwiSDR Online Radio - 10/11m dipole up 20 meters high. This type of antenna is very easy to install because there is no need . 2. 74 0 obj <>stream 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. 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. NEMA rated 4x marine grade junction box for outdoor installations. An end fed half wave antenna is one of a specific length depending on the frequency that it is to be used on, for example, an end fed half wave antenna for 80 meters is about 130 long. The WSPR map is so dense it looks like the US and Europe are just big blobs of color. Ham Radio Videos! >> The matching unit The impedance at the end of a half wave antenna is somewhere between 2000-5000 Ohms. 3 0 obj 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. google_ad_slot = "1982258389"; 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. Lowest Band of Operation: 160 meters Highest Band of Operation: 10 meters Additional Information LDG Electronics RU-9:1 Unun 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA <> 0$Ve In another life, I could have been a telephone engineer. Alternate connectors and Mounting Options are available in the. 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. This transformer converts the impedance at the end . stream They just saved you and I loads of time and frustration. Experimenting by slightly changing the wire length (+ or-) is encouraged to provide best overall performance. This undesired reflection of RF power back toward the transceiver is identified as a high voltage standing wave ratio (VSWR or SWR). << The graph below shows lengths to avoid for different collections of bands. Balun Designs. Save program output in file named 'f', and use /Filter [ /FlateDecode ] Theme designed by Papathemes. stream In fact, the 9:1 unun that I built is actually an autotransformer. q Anyway, an old friend mentioned 'MyAntenna.com' but they were closed for the summer. Downward impedance transformation by factor of 49. 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. The trick, therefore, is either 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. var sc_security="1df091cc". Click to enlarge. 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. << 7 0 obj Ham Hints 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 . I made one without doing this and it didn't work so well. <> The counterpoise wire, This transformer is designed to be used with an end fed, Approx. Drill out holes in the designated bottom of the electrical junction box for the SO239 chassis mount. Designed for use with single wire unbalanced antennas, this new addition is small, compact and perfect for quick portable/emergency installations. So for example 80m could range in length from 120 to 133 feet. 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. <> Picture 1 of 9. 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". Wait a few minutes for glue to set. Ham Satellites a more capable tuner - see AA5TB's endobj 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. /Resources << 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). For instance, to work 40m be sure the antenna is at least 10m or 33' long. (Also check out AB3AP'Swebsite and say thanks for sharing his skills. 40-10m with a 49:1 Unun. Work all bands from 80 through 10 on it. A way of connecting the analyzer to the transformer. That meant calculating all the way to 32 multiples of a half wave on 10 meters. 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. recommended on VE3EED's page because I use all halfwave Q so that it is not a halfwave multiple of any frequency you want to use. 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. The length should be calculated based on the lowest frequency to be worked. 6 0 obj (Originally published February 22, 2021). The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. endobj it is easy to pack and easy to install. google_ad_width = 160; x {avla[g#+yt]Mk"B` xp[AO8;c=\b}|8p4cSmzgU7be,+i5ci6uq.x T/s@9uk-oZX;u`=U >8rsIXW B:uUVr6a] End Fed Antennas. 22.00 + 5.00 Postage. A few more comments about this 49:1 autotransformer EFHW design. My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . 31 (A t0 B) Fold over 6 to 8 inches and twist it together. I wrote a small C program that does just what Jack did, butI used the band edges. ), Note that Jack, VE3EED,went SK several years agohe will be missed. /ModDate (D:20221212112042) 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.). An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). gnuplot Site Map 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. 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. google_ad_height = 600; Moving the pot up and down gives a feel for the SWR versus antenna impedance sensitivity. 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. 80m up, W3EDP's 84' antenna, 17' counterpoise is probably the way to go. endobj Random wire lengths you should and should not use! 32.00. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. 3 0 obj 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. u?X`f0&/Ri;W0Tn_*TX:ug <>>> //-->, The "Best" Random Wire Antenna Lengths "Can you please recommend schematics that are designed to tune setups like these? 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. is that for a given ham band there are min and max frequencies which It may not display this or other websites correctly. For calculating the length of a half wave in metres, I use 141 (MHz) for wire elements. I imported my spools from the US, but I have seen them on Ebay in the UK. SBULLET-9U-1500. Y &lD30. One is for the top of the box so that it can be hung up. For instance, to work 40m be sure the antenna is at least SSTV 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 . Well, I didn't think it would make any difference at that many multiples. I use this 8010 EFHW at home, too. doing the initial 468/f on C and D scales. 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. 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? 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. Free Postage. 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. N4UJW. Use with other lengths can potentially damage the transformer depending on power level in use. , Reprinted with permission of Hamuniverse, this is an excellent explanation of SWR and how to best me Antenna Design So, having nothing better to do one day, I re-did the calculations going out to 500 feet. Kj8~q7c? However, the radio didn't tune up very well on 15 meters. So a 49:1 impedance transformer is needed to match the 50 ohms of the coax at the feed line. Figure 3 Wiring of the 9:1 voltage unun. 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). To summarise the results WRT to reference antenna consisting of 30ft wire vertical fed with auto- You can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. Even better would be shortening to 53'. 2 0 obj understand its properties. Humor 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. 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. (wlSR9dJ_x%+VHX4FRr 3>;g^x%g'wkJu,i~#Q"2|WGf[!_m]#&1$)R.{--" 'dGO;=_B$T}". The "Super Bullet" End Fed Long Wire Antenna Matcher - 1500/3000 watt rated for Super-Punch of your signal! The graph below shows lengths to avoid for different collections of bands. One single wire, no solder connections,very simple.all the way from the tuner to the end support. There probably should be some holes for ventilation. /ProcSet 7 0 R >> 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. Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. (Note: I am not satisfied with this part of the project, so I will describe it here briefly. endobj The Short Answer Would Be That an UnUn Is a UN balanced to UN balancedmatching transformer. 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. endobj endobj The transformer usually used with an end fed wire is a 9:1 transformer. 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. Links AndWhat Is It Used For In Antennas? Jack, VE3EED - SK. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. 9:1 Unun 1.5-54MHz 2kW 9132S. Support The Site 40-30-20-17. https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. Just an FYI that I thought you might be interested in. Make sure the beginning few inches of twisted wire is not involved in the winding (i.e., just hanging down from the toroid). Turns 1 & 2 are primary windings (the short wire). | This is a 4:1 Current Balun.That means it can match a 200ohm antenna to a 50 feed line.

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