Even easier than /ProcSet 7 0 R >> 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. 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). 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. Downward impedance transformation by factor of 49. for your country and favorite modes of operation. /Type /Catalog /Name /Im0 so that it is not a halfwave multiple of any frequency you want to use. /Resources << Use only the white gaps for your antenna lengths, and if Best SWR was . /ModDate (D:20221212112042) shown in the column e. var sc_project=8077274; 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. /BitsPerComponent 8 hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r The bandwidth where SWR was below 2:1 was about one MHz. Ham Satellites 35-45, 54-64, 67-77. When on the trail, at Field Day, or whenever a good antenna is JC[
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excellent page for EFHW info - or, addressed below, to cut the wire http://udel.edu/~mm/ham/randomWire/. 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 success! Lengths to avoid are not always the same as Continue twisting the entire length of the short wire. 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. A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. Just add or subtract as needed a little at a time toget the best compromise. In another life, I could have been a telephone engineer. I will also find some sort of heat resistant packing material to help hold the transformer in place. The WSPR map is so dense it looks like the US and Europe are just big blobs of color. (Originally published February 22, 2021). Computer Help Wire lengths for the 4:1 ratio in models 4130, 4132, 4134, 4932 and 4935. 7 0 obj The short piece is for the primary winding of the transformer, and the long piece is for the secondary winding of the transformer. The unun was floating at about 15 feet above ground. For example, Cannon". 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. random wire should use 423/f. Start winding the toroid with the twisted wires at loop #1 (see schematic below). 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] 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. Anyway, an old friend mentioned 'MyAntenna.com' but they were closed for the summer. I imported my spools from the US, but I have seen them on Ebay in the UK. Use with other lengths can potentially damage the transformer depending on power level in use. Privacy Policy We'd really appreciate it! transmit frequency the impedance is so high that tuners in most rigs %PDF-1.4 To summarise the results WRT to reference antenna consisting of 30ft wire vertical fed with auto- Built with the same craftsmanship as all our other For those that enjoy endfed antennas but want to run more power, Balun Designs now offers an excellent alternative. 9:1 Unun EF Random Long wire matching Transformer with BNC or SO-239. (Center fed is so appealing because you avoid this.). This is a 4:1 Current Balun.That means it can match a 200ohm antenna to a 50 feed line. Enclosure Depth: 1.250 in. 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 /Type /XObject The trick, therefore, is either There probably should be some holes for ventilation. [ /PDF /Text /ImageI ] You can add your own wire or get the complete product from this link EFLW-3K antennas. this << See the picture below. /Count 1 JavaScript is disabled. Proudly powered by WordPress https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. This is the latest and greatest transformer design for End Fed Half Wave (EFHW) antennas. var sc_security="1df091cc". $119.95. V#X~[Z?\ZcX:-Y?&Y?IqTnayZ{jTZOub}=UTWu1G>o.,RaT
c=W>:sECXTkc=X /XObject << /Im0 9 0 R >> END FED "RANDOM WIRE" HF DIPOLE 9:1 ANTENNA RELACEMENT ELEMENT ONLY $28.99 Save up to 6% when you buy more. Thus a 1/4 wave for 20m@16ft, 40m@33ft as examples are not going to work. <>>>
(A t0 B) Fold over 6 to 8 inches and twist it together. License Study This homebrew 49:1 impedance transformer is the heart of any EFHW antenna you will build, most of the time. Suggested wire lengths for 1-61 MHz operation (measured from Bullet wire point): Bands Covered (meters) Wire Length (feet) Minimum Coax Length (feet) 40-30-20-15. Turns 1 through 14 are secondary windings (the long wire). For a better experience, please enable JavaScript in your browser before proceeding. At this point, Ive only used the 49:1 tap, but plan to take the 64131 whenever I operate portable. One is for the top of the box so that it can be hung up. Multiples are on C and 4 x 4 x 2 electrical junction box (available at big box hardware stores), One PVC DWV Test Cap (available at big box hardware stores in plumbing). 40-30-20-17. CQ-Calling All Hams! The length should be calculated based on the lowest frequency to be worked. Coverutilizes integralneoprene gasket for weatherproof integrity. x[q;`&z`uAlo#V@;hvOYt, @*Ys~_W_~W_aw_
p[N+}[t-^oLy}xz>7/~c|ZZt75;kN^=>Y+_~|b~"m*tw>xG=x6Qwz|xvz- good show chuck, you said ya picked up a 430, did i tell i fried the 0ne i got from you, can anyone point me in the direction of a 2 pill schem for the HG 2879? 0$Ve 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. << 20/40/17m. results. I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. /CreationDate (D:20221212112042) 2. After winding #2 is made and extends down the backside of the toroid, untwist the wires. Be sure to review the various lengths in the link below to obtain the lowest SWR across most if not all HF bands. So is an essential piece of gear to have. Product Reviews 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 . Wire-Lengths-for-9-1-ununs.pdf Created Date: 12/12/2022 11:20:42 AM . We recently found some good information about random wire lengths that you should and should not use. Change the program to use 423 if desired.) well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) When you're 1/2w long you're around 2k ohms or more where the balun won't under or over xform; as you approach 3/4w your z is going to drop to where a coax match can be made just by soldering the wire to the center conductor sans balun - more or less the principle of the windom and ocf dipole. installed, it is a compromise antenna but great for portable use because The length of a half wave antenna is calculated using the following formula: L (ft) = 468 / f (freq in mhz). End fed 9:1 58ft wire and 17ft counterpose wire touching ground. In total 29 contacts were made from British Columbia to Texas to Florida in 40 minutes on 20M. . which got me thinking. I did not want to put the transformer in the housing until I tested it. A level of 500-600 watts is the maximum with a further reduction onany band measuringabove 3:1. If the choices are. 74 0 obj
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SSTV Tools The other is to provide strain relief for the antenna wire). 6 Screws/ Nuts/ Washers/Wing Nuts And Ring Connectors, 1 X Mica Capacitors 100pF 500V 5%(Mouser Electronics), 1 x 4 in. In fact, the 9:1 unun that I built is actually an autotransformer. 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. Presented for your consideration by Jack, VE3EED. 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 random wire antenna is probably one of the least expensive, easiest and cheapest HF antennas to use if you have a tuner and you want to get the "most" out of a length of "random" wire without having to pull out that calculator, doing the math, getting the center insulator built orbought, running the feedline, and all the rest that goes with putting up a more elaborate antenna. Do what works best! ), Note that Jack, VE3EED,went SK several years agohe will be missed. My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . rig, often with no feedline, and the other end in the air attached to Part List: Longer wire is always more So I just wanna say thank-you!! 1863 1.49 swr 3915 2.50 7200 1.80 14.332 1.29 18.130 1.07 21.300 1.40 24.950 1.30 28.400 1.37 This is a great antenna that is . 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. <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>>
I attached the toroids to a PVC DWV test cap with 3 cable ties. When do you use a 1:1, 9:1 or a 49:1 balun? 2 0 obj (wlSR9dJ_x%+VHX4FRr 3>;g^x%g'wkJu,i~#Q"2|WGf[!_m]#&1$)R.{--" 'dGO;=_B$T}". endstream
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/Filter [ /FlateDecode ] 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. 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. My homemade 49:1 EFWH with a 60 wire (cut for 40M) would do just fine! I say run what you got and don't worry about it. 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. Lowest Band of Operation: 160 meters Highest Band of Operation: 10 meters Additional Information LDG Electronics RU-9:1 Unun These dimensions were derived from modelling the antenna in EZNEC. EFHW unun Resonant Long Wire 49:1 Transformer With BNC or SO-239 | Mobile Phones & Communication, Radio Communication Equipment, Antennas | eBay! Swr usually is all over the place and the tuner will just not do it's job. Here is an ARRL 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. While I have not done so yet, I plan on gluing the test cap to the back of the junction box. 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. 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 . google_ad_client = "ca-pub-9377297764300878"; A png image named g.png will be created. The transformer usually used with an end fed wire is a 9:1 transformer. HF & Shortwave 31 Midi Music 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.). Usually any wire length that is non resonant on the band or bands desired will work with the 4:1 ratio. 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 . endobj endobj That meant calculating all the way to 32 multiples of a half wave on 10 meters. The second smallest number I measured was 2.7pF, derived from the self resonance at 2.72 MHz with the magnetizing inductance (measured at 25.8 H) with the secondary open and the output wire folded to a small 1/2 length. bands you're intested in in a vector like the example below, by typing. << The "Super Bullet" End Fed Long Wire Antenna Matcher - 1500/3000 watt rated for Super-Punch of your signal! STORE %%EOF
8 0 obj these are the worst lengths and you want to be as far from colored Let's have a look at a few details on how to build a 49:1 impedance . Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 1500 Watts, End Fed Antennas. 73, >> . I'm looking forward to getting off work and hitting 40 & 20 meters again!! It will be good for 15m, and 10m. Drill a hole in one side for the antenna radiator wire mount (for a #8 bolt in my build). endstream Free Postage. Humor 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. AndWhat Is It Used For In Antennas?